Schneider Euro PC

Reply 220 of 231, by mkarcher

Posted on 2024-07-26, 18:15

mkarcher Offline

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RetroBard wrote on 2024-07-26, 16:50:

Kekkula wrote on 2024-07-21, 19:17:

Great if the picomem is now working with Euro Pc 1. I have to wait if it gets open sourced, it would be fun project to build.

https://github.com/FreddyVRetro/ISA-PicoMEM

PicoMEM README.md wrote:

License

Hardware and Software are currently closed.

Reply 221 of 231, by Jinxter

Posted on 2025-08-16, 15:22

Jinxter Offline

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Posts: 246
Joined: 2016-03-15, 18:42
Location: Norway

Hi
I first thought my clock on my EuroPC was not working. But then i see that when i use the EuroPC boot disk (German) i get correct time.
But when using MS-Dos 3.31 og MS-Dos 6.22 i get wrong time (00:00:00).
The EuroPC boot disk is not using a driver for the clock, but it seams that the version of does is a special version for EuroPC. This is probably fixed to use the EuroPC clock.

Do we need a driver for using the internal clock?

Check out my YouTube channel: Retro Erik https://www.youtube.com/c/RetroErik
My collection: https://retro.hageseter.com
X: https://x.com/Retro_Erik

Reply 222 of 231, by Predator99

Posted on 2025-10-06, 15:24

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I noticed this thread exists before posting this in a new one...I dont like this to be lost therefore I copy it here and delete the other post...sorry:

I recently got a Schneider EURO PC I with a battery damage. The PC complained about the missing RTC, was not displaying anything on the internal Video and a external VGA was also not initialized.

The attachment IMG_4057r.jpg is no longer available

I was able to fix a trace to the PVC4 and the Video is working again. But the traces to the RTC are too small and there is too much damage. Without RTC I was not able to enter the BIOS-Setup and configure the PC to boot from VGA.

Therefore I modified the BIOS...:
- no checksum
- no wait for keypress on error
- RTC data hardwired in BIOS image. Needs to be entered at offset 6F8A - 6F99, after the "XXXXX", 16 Bytes
- XT-IDE included

With this I am able to configure the PC without RTC. A damaged PVC4 should also be no Problem when you use an external graphics card. Therefore most battery damages on the board are no problem anymore. All traces below the battery belong to the RTC or the PVC4.

The configuration data can be taken from a working PC oder from PCem. The attahced EURORTC.COM reads the data from the CMOS. Only one byte (the lower from the displayed) needs to be entered in the ROM-image. Its preconfigured for 9.77 MHz and start with external VGA now. Therefore for most people there should be no need to change it.

Let me know if its useful for your or if you still have trouble with a beeping and not starting EURO-PC 😉

The attachment EuroPC-noRTCV2.zip is no longer available

The attachment EURORTC.zip is no longer available

The attachment WhatsApp Bild 2025-10-04 um 20.52.32_b34d3220.jpg is no longer available

The attachment Screenshot 2025-10-04 215316.png is no longer available

10 00 Time: Seconds
21 00 Time: Minutes
32 00 Time: Hour
43 01 Date: Day
54 01 Date: Month
65 88 Date: Year
7
86 00 unused
97 00 unused
108 00 unused
11
129 Floppy/HD config (int/ext/HD20): i.e. 02:int 720kb, ext. no, HD20 no, boot internal
13
14A 00:RAM/Mouse/Joystick/Video startup 
15	00:640kb, Mouse/Joystick disabled 
16	08:512kb, Mouse/Joystick disabled 
17	02:640kb, Joystick
18	01:640kb, Mouse
19	0A:512kb, Joystick
20	09:512kb, Mouse
21	28:512kb, Mouse/Joystick disabled 
22
23B CPU Speed, Video config
24           0123 4567
25	03 0000 0011:4.77 MHz int. Video disabled, monitor detection disabled. Video Startup: Monochrome
26	83 1000 0011:9.54 MHz int. Video disabled, monitor detection disabled. Video Startup: Monochrome
27	43 0100 0011:7.15 MHz int. Video disabled, monitor detection disabled. Video Startup: Monochrome
28	17 0001 0111:4.77 MHz int. Video mono, monitor detection disabled. Video Startup: Monochrome
29	07 0000 0111:4.77 MHz int. Video color, monitor detection disabled. Video Startup: Monochrome
30	16 0001 0110:4.77 MHz int. Video mono, monitor detection disabled. Video Startup: Color 80
31	15 0001 0101:4.77 MHz int. Video mono, monitor detection disabled. Video Startup: Color 40
32	05 0000 0101:4.77 MHz int. Video color, monitor detection disabled. Video Startup: Color 40
33	04 0000 0100:4.77 MHz int. Video color, monitor detection disabled. Video Startup: Special Adapter
34	94 1001 0100:9.54 MHz int. Video mono, monitor detection enabled. Video Startup: Special Adapter
35
36	Bit 0+1: 00: 4.77 MHz, 10:9.54 MHz, 01: 7.15 MHz
37	Bit 2: 0, unused
38	Bit 3: int. Video: 0: disabled/color, 1:mono
39	Bit 5: int. Video disabled: 0:disabled 1:enabled
40	Bit 4: monitor detection: 1:enabled, 0:disabled
41	Bit 6+7: Video Startup: 11:Monochrome, 10:Color 80, 01:Color 40, 10: special adapter
42
43C country: 00:DEU 0C:Greece 02:GB ...
44
45D checksum? Different value with each config change
46
47E always 00
48F always 01

Last edited by Predator99 on 2025-10-19, 19:02. Edited 4 times in total.

Reply 223 of 231, by Predator99

Posted on 2025-10-06, 18:35

Predator99 Offline

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That was a lot of work. It was fun and I learned some new things. I think I will not keep my notes, therefore I add the most important parts below. Base is the BIOS 3.01. As you can see it runs well in the EURO PC I.

You can also see there are POST codes on port 80 after each step. But my card displays many "FF"-codes in between, so its of no use. Dont know why, maybe you can check this, too.

Summarized:
- RTC is at port 25A.
- RTC read at sub F000:EF66: Byte to be read submitted in CL. Result in AL, CF=1 on error.
- RTC write at sub F000:E952: Byte to be written submitted in CL. Value in AL.
- RTC errors are triggered in DI, relevant messages are printed at sub F000:92DF
- normal BIOS Messages are printed with sub F000:D607, the offset of the string needs to be in BP
- the setup of the video is in a sub at F000:ECC5, didnt investigate this completely
- I assume output of beep-codes is done in F000:F7F2 and F000:E821, but I didnt verify
- boot from disk is executed from F000:D399 - D3A8 with the final request to enter Setup on error and wait for keypress
- the included BIOS/RTC Setup procedure ist completely independent and can be transferred to a .COM without problems.
- WD hard disk Setup is also included, didnt take a look at it and used the space for XT-IDE
- BIOS checksum verified at F000:D1DD

1F000:8000 EA000001FA    JMP	FA01:0000	(=F000:A010) BIOS Setup
2
3****Sub: Display RTC error codes in DI**********
4F000:92DF E8BC6B        CALL	FE9E                    load DS           
5F000:92E2 0BFF          OR	DI,DI                               
6F000:92E4 7421          JZ	9307                no error, return            
7F000:92E6 F7C70080      TEST	DI,8000                error code in DI      1000 0000 0000 0000      
8F000:92EA 7405          JZ	92F1                               
9F000:92EC C6061204FF    MOV	BYTE PTR [0412],FF                 [0412] seems to trigger of if forced to run setup
10F000:92F1 B90700        MOV	CX,0007    			7 possible error codes                        
11F000:92F4 BB5FDB        MOV	BX,DB5F                            
12 F000:92F7 D1EF          SHR	DI,1                                
13 F000:92F9 7308          JNB	9303    all OK, nor error                           
14 F000:92FB 2E            CS:	                                   
15 F000:92FC 8B2F          MOV	BP,[BX]         message lookup table    
16+0 DED8 RTC error         bit 1
17+2 DEC1 RTC time eoor     bit 2
18+4 DE4C Setup checksum error
19+6 DEAC RTC Status corrected
20+8 DEE2 Video Setup error
21+A DF49 Video RAM bad
22+C DCDA monitor type not recognized bit 7
23+F DCF6 mouse port enabled
24+16 DC8C Joystick enabled
25 F000:92FE 53            PUSH	BX                                 
26 F000:92FF E80543        CALL	D607                               
27 F000:9302 5B            POP	BX                                 
28 F000:9303 43            INC	BX                                 
29 F000:9304 43            INC	BX                                 
30 F000:9305 E2F0          LOOP	92F7                               
31F000:9307 C3            RET	       
32
33
34F000:A010 51            PUSHF           (=FA01:0000), execute BIOS Setup, can be started anytime with a CALL FAR)
35F000:A011 51            PUSH	AX           
36F000:A012 51            PUSH	BX                           
37F000:A013 51            PUSH	CX                                 
38F000:A014 52            PUSH	DX                                 
39F000:A015 55            PUSH	BP                                 
40F000:A016 56            PUSH	SI                                 
41F000:A017 57            PUSH	DI                                 
42F000:A018 1E            PUSH	DS                                 
43F000:A019 06            PUSH	ES                                 
44F000:A01A 0E            PUSH	CS                                 
45F000:A01B 1F            POP	DS                                 
46F000:A01C E81500        CALL	A034                               
47F000:A01F 07            POP	ES                                 
48F000:A020 1F            POP	DS                                 
49F000:A021 5F            POP	DI                                 
50F000:A022 5E            POP	SI                                 
51F000:A023 5D            POP	BP                                 
52F000:A024 5A            POP	DX                                 
53F000:A025 59            POP	CX                                 
54F000:A026 5B            POP	BX                                 
55F000:A027 58            POP	AX                                 
56F000:A028 9D            POPF	                                   
57F000:A029 CB            RETF	       
58
59F000:AB21 EAF0FF00F0    JMP	F000:FFF0       Setup: Reboot after RTC saved
60F000:B21E EA52E900F0    JMP	F000:E952               Setup: Write RTC after changes

…Show last 303 lines

61F000:B201 EA66EF00F0    JMP	F000:EF66  Setup: Read RTC
62
63
64F000:B635	end of setup code, start of setup Messages
65F000:C01D	Setup end
66
67F000:D08D BD13DC        MOV	BP,DC13   message "internal FDC enabled"                        
68F000:D090 E87405        CALL	D607                               
69
70F000:D0E8 BD29DC        MOV	BP,DC29     "boot drive set to external drive"                       
71F000:D0EB E81905        CALL	D607              
72
73F000:D11A BD4ADC        MOV	BP,DC4A		"disk error"
74F000:D11D E8E704        CALL	D607                               
75
76F000:D156 B002          MOV	AL,02      this is the actual initialization start,display POST code 02
77F000:D158 E680          OUT	80,AL                              
78F000:D15A FC            CLD	     
79
80F000:D1C9 B005          MOV	AL,05                              
81F000:D1CB E680          OUT	80,AL                              
82F000:D1CD BE0080        MOV	SI,8000                            
83F000:D1D0 B90080        MOV	CX,8000                            
84F000:D1D3 32C0          XOR	AL,AL                              
85F000:D1D5 2E            CS:	                                   
86F000:D1D6 0204          ADD	AL,[SI]                            
87F000:D1D8 46            INC	SI                                 
88F000:D1D9 E2FA          LOOP	D1D5   verify checksum, POST 05                             
89F000:D1DB 0AC0          OR	AL,AL                              
90F000:D1DD 740E          JZ	D1ED                               
91F000:D1DF B233          MOV	DL,33                              
92F000:D1E1 BCE7D1        MOV	SP,D1E7                            
93F000:D1E4 E90B26        JMP	F7F2                               
94F000:D1E7 E9D1FA        JMP	CCBB                               
95F000:D1EA F4            HLT	                                   
96F000:D1EB EBFC          JMP	D1E9                               
97F000:D1ED B006          MOV	AL,06     Checksum OK                         
98
99F000:D1F5 33FF          XOR	DI,DI                    0000 0000 0000 0000 (DI tracks the RTC error codes during Startup)
100F000:D27B 33FF          XOR	DI,DI                    0000 0000 0000 0000
101
102F000:D2A7 BD40D4        MOV	BP,D440    Copyright Schneider                        
103F000:D2AA E85A03        CALL	D607                               
104
105F000:D2BD 813E400053FF  CMP	WORD PTR [0040],FF53      	+++++++++++++0040	4	Interrupt Vector for INT 10h (video)    ,FF53 is IRET  
106F000:D2C3 751D          JNZ	D2E2                               
107F000:D2C5 813E420000F0  CMP	WORD PTR [0042],F000               
108F000:D2CB 7515          JNZ	D2E2                               
109F000:D2CD 81CF1080      OR	DI,8010              DI          1000 0000 0001 0000    Video Setup error!
110F000:D2D1 E84D15        CALL	E821                             Speaker Beep code?  
111F000:D2D4 C706400065F0  MOV	WORD PTR [0040],F065          +++++++++++++0040	4	Interrupt Vector for INT 10h (video)  
112
113F000:D2DF E8E319        CALL	ECC5  set screen mode                             
114F000:D2E2 BD40D4        MOV	BP,D440  Copyright 1988-1989 Schneider                           
115F000:D2E5 E81F03        CALL	D607                               
116
117F000:D2EC E8F0BF        CALL	92DF       check DI error code
118F000:D2EF B00F          MOV	AL,0F                              
119F000:D2F1 E680          OUT	80,AL                              
120F000:D2F3 E8360F        CALL	E22C               Setup CPU speed
121
122F000:D394 803E1204FF    CMP	BYTE PTR [0412],FF                 
123F000:D399 7509          JNZ	D3A4      
124F000:D39B BDF4DE        MOV	BP,DEF4                            
125F000:D39E E86602        CALL	D607         message run setup           
126F000:D3A1 E8BA02        CALL	D65E         wait for keypress on error
127F000:D3A4 B01C          MOV	AL,1C                              
128F000:D3A6 E680          OUT	80,AL        error code 1C            
129F000:D3A8 CD19          INT	19        boot the system                         
130F000:D3AA CD18          INT	18                                 
131
132F000:D4E0 E82E01        CALL	D611                               
133F000:D4E3 BD64DE        MOV	BP,DE64        hd Setup error   
134F000:D4E6 E81E01        CALL	D607  
135
136
137F000:D577 B10F          MOV	CL,0F     sub: Setup System status                        
138F000:D579 E8EA19        CALL	EF66      result in AX                         
139F000:D57C 7238          JB	D5B6                               
140F000:D57E 3C01          CMP	AL,01                              
141F000:D580 7410          JZ	D592                               
142F000:D582 B001          MOV	AL,01                              
143F000:D584 E8D713        CALL	E95E                               
144F000:D587 722D          JB	D5B6                               
145F000:D589 B234          MOV	DL,34                              
146F000:D58B E86422        CALL	F7F2                               
147F000:D58E 81CF0880      OR	DI,8008         DI 8008        1000 0000 0000 1000         
148F000:D592 E8A905        CALL	DB3E                               
149F000:D595 721F          JB	D5B6                               
150F000:D597 E8D819        CALL	EF72                               
151F000:D59A 721A          JB	D5B6                               
152F000:D59C 3AC3          CMP	AL,BL                              
153F000:D59E 750B          JNZ	D5AB                               
154F000:D5A0 FEC1          INC	CL                                 
155F000:D5A2 E8CD19        CALL	EF72                               
156F000:D5A5 720F          JB	D5B6                               
157F000:D5A7 3AC7          CMP	AL,BH                              
158F000:D5A9 7415          JZ	D5C0                               
159F000:D5AB B224          MOV	DL,24                              
160F000:D5AD E84222        CALL	F7F2     Speaker                           
161F000:D5B0 81CF0480      OR	DI,8004          DI 8004            1000 0000 000 0100      
162F000:D5B4 EB0A          JMP	D5C0                               
163F000:D5B6 B244          MOV	DL,44                              
164F000:D5B8 E83722        CALL	F7F2     Speaker                          
165F000:D5BB 83CF01        OR	DI,+01                  DI 01     0000 0000 0000 0001        RTC error!
166F000:D5BE EB0D          JMP	D5CD                               
167F000:D5C0 E83502        CALL	D7F8                               
168F000:D5C3 7308          JNB	D5CD                               
169F000:D5C5 B214          MOV	DL,14                              
170F000:D5C7 E82822        CALL	F7F2                               
171F000:D5CA 83CF02        OR	DI,+02                        0000 0000 0000 00010
172F000:D5CD C3            RET	                
173
174
175F000:E22C		Sub: Setup speed
176
177E8350B call ef66       get CPU Speed / RTC
178F000:jb e239
179                                 
180F000:E233 24C0          AND	AL,C0                              
181F000:E235 3CC0          CMP	AL,C0                              
182F000:E237 750D          JNZ	E246                               
183F000:E239 B202          MOV	DL,02                              
184F000:E23B E8B415        CALL	F7F2                               
185F000:E23E BD9ADE        MOV	BP,DE9A         Speed Setup error                   
186F000:E241 E8C3F3        CALL	D607                               
187F000:E244 32C0          XOR	AL,AL                              
188F000:E246 BA5502        MOV	DX,0255                            
189F000:E249 0236B604      ADD	DH,[04B6]                          
190F000:E24D EE            OUT	DX,AL                              
191F000:E24E 32E4          XOR	AH,AH                              
192F000:E250 8BD8          MOV	BX,AX                              
193F000:E252 0C11          OR	AL,11                              
194F000:E254 E663          OUT	63,AL                              
195F000:E256 B103          MOV	CL,03                              
196F000:E258 D2C3          ROL	BL,CL                              
197F000:E25A 9A030000C0    MOV BP, DF3B  "CPU Speed is    "              
198F000:E25F 90            CALL D5F7                               
199F000:E260 2E            CS:	                                   
200F000:E261 8BAFAEDF      MOV	BP,[BX+DFAE]                       
201F000:E265 E88FF3        CALL	D5F7                               
202F000:E268 BDD5DC        MOV	BP,DCD5   "MHZ"                       
203F000:E26B E899F3        CALL	D607                               
204F000:E26E C3            RET	
205
206F000:E05B         CLI	BIOS start
207F000:E05C B011          MOV	AL,11                              
208F000:E05E E663          OUT	63,AL                              
209F000:E060 32C0          XOR	AL,AL                              
210F000:E062 E680          OUT	80,AL  		POST code 00                            
211F000:E064 33C0          XOR	AX,AX                              
212F000:E066 8ED8          MOV	DS,AX                              
213F000:E068 8B2E7204      MOV	BP,[0472]                          set to 1234h after initial power up telling a warm boot to skip mem check
214F000:E06C BB00D0        MOV	BX,D000                            
215F000:E06F 8EC3          MOV	ES,BX                              
216F000:E071 33FF          XOR	DI,DI                              
217F000:E073 BE54D4        MOV	SI,D454                            
218F000:E076 B91100        MOV	CX,0011                            
219F000:E079 F3            REPZ	                                   
220F000:E07A 2E            CS:	                                   
221F000:E07B A6            CMPSB	                                   
222F000:E07C E303          JCXZ	E081                               
223F000:E07E E9D5F0        JMP	D156     continue with init of this BIOS at D156                         
224F000:E081 B001          MOV	AL,01                              
225F000:E083 E680          OUT	80,AL  error code 01 on port 80                            
226F000:E085 BE9EE9        MOV	SI,E99E                            
227F000:E088 BF56D1        MOV	DI,D156                            
228F000:E08B BB58F8        MOV	BX,F858                            
229F000:E08E EA1B0000D0    JMP	D000:001B      	seems to check for an optional ROM at D000 segment and if detected jumps to D000:001B
230
231F000:E646 81C70004      ADD	DI,0400       0100 0000 0000    DI error code 
232
233F000:E721 BD76DB        MOV	BP,DB76   "boot error"                         
234F000:E724 E8E0EE        CALL	D607                               
235
236F000:E804 BD57DF        MOV	BP,DF57             8087            
237F000:E807 E8FDED        CALL	D607      
238
239Sub: write RTC data (CL)
240F000:E952 1E            PUSH	DS                                 RTC write, value in cl
241F000:E953 E84815        CALL	FE9E                               
242F000:E956 BA5A02        MOV	DX,025A                            
243F000:E959 0236B604      ADD	DH,[04B6]                          
244F000:E95D 1F            POP	DS                                 
245F000:E95E 53            PUSH	BX                                 
246F000:E95F 8AE0          MOV	AH,AL                              
247F000:E961 EC            IN	AL,DX                              
248F000:E962 BB280D        MOV	BX,0D28                            
249F000:E965 4B            DEC	BX                                 
250F000:E966 F9            STC	                                   
251F000:E967 741C          JZ	E985                               
252F000:E969 EC            IN	AL,DX                              
253F000:E96A 240F          AND	AL,0F                              
254F000:E96C 75F7          JNZ	E965                               
255F000:E96E 8AC1          MOV	AL,CL                              
256F000:E970 90            NOP	                                   
257F000:E971 EE            OUT	DX,AL                              
258F000:E972 8AC4          MOV	AL,AH                              
259F000:E974 D0E8          SHR	AL,1                               
260F000:E976 D0E8          SHR	AL,1                               
261F000:E978 D0E8          SHR	AL,1                               
262F000:E97A D0E8          SHR	AL,1                               
263F000:E97C EE            OUT	DX,AL                              
264F000:E97D 8AC4          MOV	AL,AH                              
265F000:E97F 90            NOP	                                   
266F000:E980 90            NOP	                                   
267F000:E981 90            NOP	                                   
268F000:E982 90            NOP	                                   
269F000:E983 EE            OUT	DX,AL                              
270F000:E984 F8            CLC	                                   
271F000:E985 5B            POP	BX                                 
272F000:E986 C3            RET	  
273
274F000:ECC5	sub: Video Setup
275looks atequipment list word at 0000:0410h
276........ ..XX....   Initial video mode
277                      01 - 40 column color
278                      10 - 80 column color
279                      11 - monochrome
280                      00 - none of the Above
281F000:ECD2 8A1E1004      MOV	BL,[0410]                          
282F000:ECD6 C606100430    MOV	BYTE PTR [0410],30                Video monochrome! 
283F000:ECDB CD10          INT	10           AL=00h Textmodus, 40 x 25 Zeichen, 16 Graustufen                      
284F000:ECDD B800B0        MOV	AX,B000     check MDA RAM                       
285…
286F000:ED05 C606100420    MOV	BYTE PTR [0410],20         10 - 80 column color        
287F000:ED0A 33C0          XOR	AX,AX                              
288F000:ED0C CD10          INT	10                             AL=00h Textmodus, 40 x 25 Zeichen, 16 Graustufen    
289F000:ED0E B800B8        MOV	AX,B800     ********Check CGA RAM******       
290…
291F000:ED39 E82A02        CALL	EF66                      read RTC         
292F000:ED3C 7308          JNB	ED46                               
293F000:ED3E 83CF01        OR	DI,+01                  DI 01           0000 0000 0000 0001	RTC error
294F000:ED41 E8DDFA        CALL	E821                               Speaker?
295...
296F000:ED67 81CF1080      OR	DI,8010                      DI8010      1000 0000 0001 0000 Video Setup error!
297…
298F000:ED73 E8F001        CALL	EF66                               RTC lesen
299F000:ED76 7215          JB	ED8D                               
300F000:ED78 F7C70C00      TEST	DI,000C                           DI  0000 0000 0000 1100 Setup checksum/RTC Status correted
301…
302F000:ED97 83CF40        OR	DI,+40                       DI 40      0000 0000 0100 0000
303…
304F000:EDC2 81CF1080      OR	DI,8010                            DI 8010	1000 0000 0001 0000	Video Setup error
305..
306F000:EDCA 81CF1080      OR	DI,8010        1000 0000 0001 0000             Video Setup error       
307…
308F000:EE8E B90020        MOV	CX,2000                            
309F000:EE91 BAD803        MOV	DX,03D8                 use CGA           
310F000:EE94 BB00B8        MOV	BX,B800                            
311F000:EE97 32C0          XOR	AL,AL                              
312F000:EE99 80FC30        CMP	AH,30                              
313F000:EE9C 750B          JNZ	EEA9                               
314F000:EE9E B90008        MOV	CX,0800                AH=30            
315F000:EEA1 BAB803        MOV	DX,03B8             use MDA               
316F000:EEA4 BB00B0        MOV	BX,B000                            
317…
318F000:EED3 83CF20        OR	DI,+20                             0000 0000 0010 0000
319F000:EED6 E848F9        CALL	E821                               Speaker
320…
321F000:EEEA 83CF20        OR	DI,+20                             0000 0000 0010 0000
322F000:EEED E831F9        CALL	E821                               Speaker?
323...
324F000:EF44 C3            RET
325
326Sub: Read RTC, input Byte in CL
327F000:EF66 1E            PUSH	DS                                 
328F000:EF67 E8340F        CALL	FE9E                               
329F000:EF6A BA5A02        MOV	DX,025A                            
330F000:EF6D 0236B604      ADD	DH,[04B6]             add Offset to port?
331F000:EF71 1F            POP	DS                                 
332F000:EF72 53            PUSH	BX                                 
333F000:EF73 EC            IN	AL,DX                              
334F000:EF74 BB280D        MOV	BX,0D28                            
335F000:EF77 4B            DEC	BX                                 
336F000:EF78 F9            STC	                                   
337F000:EF79 741D          JZ	EF98                               
338F000:EF7B EC            IN	AL,DX                              
339F000:EF7C 240F          AND	AL,0F                              
340F000:EF7E 75F7          JNZ	EF77                               
341F000:EF80 8AC1          MOV	AL,CL                              
342F000:EF82 90            NOP	                                   
343F000:EF83 EE            OUT	DX,AL                              
344F000:EF84 90            NOP	                                   
345F000:EF85 90            NOP	                                   
346F000:EF86 90            NOP	                                   
347F000:EF87 90            NOP	                                   
348F000:EF88 EC            IN	AL,DX                              
349F000:EF89 8AE0          MOV	AH,AL                              
350F000:EF8B D0E4          SHL	AH,1                               
351F000:EF8D D0E4          SHL	AH,1                               
352F000:EF8F D0E4          SHL	AH,1                               
353F000:EF91 D0E4          SHL	AH,1                               
354F000:EF93 EC            IN	AL,DX                              
355F000:EF94 240F          AND	AL,0F                              
356F000:EF96 0AC4          OR	AL,AH                              
357F000:EF98 5B            POP	BX                                 
358F000:EF99 C3            RET		Carry = error, result in AL
359
360F000:F086 83E730        AND	DI,+30              0000 0000 0011 0000        
361
362
363F000:FFF0 EA5BE000F0    JMP	F000:E05B	BIOS init

Last edited by Predator99 on 2025-10-19, 06:58. Edited 2 times in total.

Reply 224 of 231, by Predator99

Posted on 2025-10-06, 21:12

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Jinxter wrote on 2025-08-16, 15:22:
Hi I first thought my clock on my EuroPC was not working. But then i see that when i use the EuroPC boot disk (German) i get cor […]
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Hi
I first thought my clock on my EuroPC was not working. But then i see that when i use the EuroPC boot disk (German) i get correct time.
But when using MS-Dos 3.31 og MS-Dos 6.22 i get wrong time (00:00:00).
The EuroPC boot disk is not using a driver for the clock, but it seams that the version of does is a special version for EuroPC. This is probably fixed to use the EuroPC clock.

Do we need a driver for using the internal clock?

On BIOS level date & time is managed through INT 1A
Int 1A/AH=00h - TIME - GET SYSTEM TIME
Int 1A/AH=01h - TIME - SET SYSTEM TIME
Int 1A/AH=02h - TIME - GET REAL-TIME CLOCK TIME (AT,XT286,PS)
Int 1A/AH=03h - TIME - SET REAL-TIME CLOCK TIME (AT,XT286,PS)
Int 1A/AH=04h - TIME - GET REAL-TIME CLOCK DATE (AT,XT286,PS)
Int 1A/AH=05h - TIME - SET REAL-TIME CLOCK DATE (AT,XT286,PS)

Int 1A points to F000:FE6E

1F000:FE6E FB            STI	             Int 1A date and time                      
2F000:FE6F 57            PUSH	DI                                 
3F000:FE70 80FC0B        CMP	AH,0B                              
4F000:FE73 7203          JB	FE78                               
5F000:FE75 E9CCFA        JMP	F944                               
6F000:FE78 50            PUSH	AX                                 
7F000:FE79 D0E4          SHL	AH,1                               
8F000:FE7B 8AC4          MOV	AL,AH                              
9F000:FE7D 32E4          XOR	AH,AH                              
10F000:FE7F 8BF8          MOV	DI,AX                              
11F000:FE81 58            POP	AX                                 
12F000:FE82 2E            CS:	                                   
13F000:FE83 FFA53DFF      JMP	[DI+FF3D]

At FF3D there is table where the services are located:
00 F8E9
01 F8B6
02 F8CA
03 F8EF
04 F917

So for the service 02 "GET REAL-TIME CLOCK TIME" you are directed to F000:F8CA

1F000:F8CA 53            PUSH	BX          Int 1A AH02                       
2F000:F8CB 8ADA          MOV	BL,DL                              
3F000:F8CD B102          MOV	CL,02                              
4F000:F8CF E894F6        CALL	EF66                               
5F000:F8D2 7218          JB	F8EC                               
6F000:F8D4 8AE8          MOV	CH,AL

Looking at my data above, RTC is read with "CALL EF66" and byte 02 is requested.

Thats all standard, no driver is required to get date & time 😀

And verified against the M3002 datasheet:
https://mixinc.net/atari/datasheet/M3002.pdf

Bytes 8-E are configuration data
Byte 02 is the hour

The attachment Screenshot 2025-10-06 232809.png is no longer available

Reply 225 of 231, by Predator99

Posted on 2025-10-07, 14:56

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Thanks for the questions regarding the time 😉 I have entered some data in Byte 0-7 of my noRTC ROM-image and the corresponding date/time is shown in DOS after booting the ROM-image in PCem.
It is displayed correctly in the Schneider DOS 3.3 and also in standard MS-DOS 5.5

Thefore configuration data is only stored in Bytes 8-E, I will find out its meaning as well later.

The attachment RTC1.jpg is no longer available

The attachment RTC2.jpg is no longer available

The attachment RTC3.jpg is no longer available

Reply 226 of 231, by Predator99

Posted on 2025-10-19, 19:24

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OK I understand there is no feedback...there is no need for owners of fully working EURO-PCs.

There is some interesting information in the Schneider "Techniker Schulung" Manual mentioned in this thread:
https://oldcrap.org/wp-content/uploads/2023/0 … pc-training.pdf

The I/O port adresses are mentioned here:

The attachment Screenshot 2025-10-09 190503.png is no longer available

Note 1 means the base adress can be modified by closing the jumper "JS9". The RTC at 25A/25B is switched to 35A/35B when closed. This is one thing I didnt understand in the BIOS-code so far: The offset is stored at [04B6] and is added to the base address.

In the mean time I figured out the meaning of all bytes of the RTC and added it in my post above.

I also can confirm the software for the ATI Graphics Solution (which has also the PVC4) works on the EURO-PC:
ftp://ftp.mindcandydvd.com/pub/drivers/ATI/Gr … ics%20Solution/
See this thread
Paradise PVC4 CGA card : looking for video BIOS [ROM restored !]

I also made some tests with ROMs for 1.44 MB Floppy support (DTK, 2M-XBIOS, ...) but I didnt have success so far. Did anybody else try this? As far as I understand the controller WD37C65BJM supports the required data rate of 500Kb/sec so this should work?

Reply 227 of 231, by Jinxter

Posted on 2025-10-19, 21:06

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Location: Norway

Predator99 wrote on 2025-10-19, 19:24:

OK I understand there is no feedback...there is no need for owners of fully working EURO-PCs.

I am following and reading this with pleasure. Maybe we could be more supportive as a community, but i guess we (I) don't want to clutter a fine thread with non-essential stuff.
Anyway, i am sure alle the EuroPC owner her on Vogons are following this thread - and your postings. Keep up the good work.

Check out my YouTube channel: Retro Erik https://www.youtube.com/c/RetroErik
My collection: https://retro.hageseter.com
X: https://x.com/Retro_Erik

Reply 228 of 231, by konc

Posted on 2025-10-20, 09:52

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Predator99 wrote on 2025-10-19, 19:24:

I also can confirm the software for the ATI Graphics Solution (which has also the PVC4) works on the EURO-PC:

Wait, the CW16800 of the Graphics Solution is the PVC4, οr where there cards with an actual PVC4 chip?
(Also what about the Small Wonder that has a different chipset but also switches modes with the same utility?)

That's great news and thanks for trying. Although SIMCGA not being necessary with the Schneider means half of my childhood was a lie!

Reply 229 of 231, by Predator99

Posted on 2025-10-20, 13:06

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Indeed, reading the the thread again, the driver disk seems to be for the ATI graphics solution and not for the PVC4-card the topic is about. Therefore the only ISA card with a PVC4 seems to be this one which is not ATI:
https://theretroweb.com/expansioncards/s/leanord-12t-cga
At least all tests I tried worked on my EURO-PC. Currently I have a ISA-VGA as primary and PVC4-Hercules as secondary display. But I have not finished testing yet.

As I am not going to fix my RTC my goal is to set the BIOS to start with PVC4-CGA. And try to switch the PVC4 under DOS from CGA to Hercules and activate the ISA-VGA if needed. So I have full flexibility without changing the ROM. I hope my analysis of the BIOS will help to get this running. The datasheet and programming instruction for the PVC4 is also available under archive.org.

btw: If have tested several ISA-VGAs (8-bit & 16-bit). The only one accepted by the EURO-PC is a 8-bit ET-3000. Seems to be very selective. EGA-cards run without problem.

The attachment ET3000.jpg is no longer available

Reply 230 of 231, by Predator99

Posted on 2025-10-22, 19:24

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I had a better idea to deal with my RTC Problem and did a new approach.

My idea was to have a copy of the RTC data in RAM. This way it can be altered with the setup programm and the settings are kept after a reboot.

So the first goal was to find a location in the RAM that "survives" a warm boot. Some content is kept, however many locations i.e. the IVT are overwritten by DOS.
So I decided to use some bytes "in the middle" of the RAM, I chose 6060:0 as a start. This area "survived" a reboot with Ctrl-Alt-Del.

However, when saving the RTC-data with setup, setup performs a "hard" reboot with a RAM-check. During this check the RAM is totally cleared.

If a RAM-test is performed or not is checked with the instruction
F000:EAAE 813E72043412 CMP WORD PTR [0472],1234
and can be disabled.

I also modified the setup: After saving with "enter" it does not do a reboot any longer but returns to where it was called from. This is done bye replacing
F000:AB21 EAF0FF00F0 JMP F000:FFF0
with NOPs.

Then I implemented my idea:
I store the "Default" values for the RTC in the ROM-Image at location 0A00 (=F000:8A00). These can be altered very easily, so you dont have to use Setup everytime you start the PC. On startup I check if the copy in RAM at 6060:0 is already there. I do this with a status word at 6060:0 (6666=already there / other value: copy again). If not, default values are copied to RAM (Byte 0-F, starting at 6060:2). This procedure is now at F000:0990.

Then I did a rewrite of the procedures...
- RTC read at sub F000:EF66: Byte to be read submitted in CL. Result in AL, CF=1 on error.
- RTC write at sub F000:E952: Byte to be written submitted in CL. Value in AL.
...not to read/write the data from/to the RTC but to use the values stored at 6060:2.

It works perfectly…! I can enter whatever I want in the setup, changes are applied after Pressing Ctrl-Alt-Del. I can choose between all graphics Options (ISA-VGA, PVC4-Hercules, PVC4-CGA) without opening the PC. Of course the settings are overwritten when some application uses the RAM at 6060:0. But this is not a problem, after the next reboot default values are used again.

There should be a conflict between ISA-VGA and PVC4-CGA, but it works in parallel.
- my initial configuration is: internal video:color / Video Startup:Color/Graphics 80: PC boots with BIOS Messages and DOS on ISA-VGA, but CGA blinking Cursor is visible on PVC4-Video. CGA games Display on the internal Video. You have to type "mode co80" to see the DOS screen on the PVC4-CGA.

This is what setup looks like on PVC4-CGA after turning on the PC:

The attachment ss1.png is no longer available

You can view the RTC data in the RAM with debug. Its
00 00 00 24 05 25 36 37 38 02 09 86 0A D3 00 01

The attachment ss2.png is no longer available

Its the same what is entered in the ROM-image starting at 000A00

The attachment minipro.jpg is no longer available

Then we press Ctrl-Alt-Esc and switch Setup to: internal Video: mono / Video Startup: monochrome, Monitor detection disabled.

The attachment ss3.png is no longer available

Save the settings and view the result in the same debug session. RTC data changed to
00 00 00 26 07 21 36 37 38 02 29 97 0A 04 01 01

The attachment ss4.png is no longer available

You can also see I changed the date. With this you can create a custom configuration: Copy the bytes of the configuration you need in the ROM-image and it will be used as default.

Reply 231 of 231, by Predator99

Posted on 2025-10-22, 19:26

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Then reboot with Ctrl-Alt-Del. DOS boots with ISA-VGA. EGA/VGA games start on ISA-VGA. Switch DOS to Hercules with the "mode mono" command. Now Hercules games start on the PVC4-Hercules.

The attachment ss5.png is no longer available

BIOS-screen:

The attachment Boot.jpg is no longer available

Image file

The attachment EuroPC-noRTCV3.zip is no longer available

As before...only useful for EURO-PCs with non-working RTC 😀

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