VOGONS


Reply 220 of 395, by LABS

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H1 header with GND and PB1 pins is made for debugging. The ATmega outputs all incoming/outgoing commands and parameters via this header in UART format with 1MHz baud rate. It is TX-only. I used FT232RL-based UART-to-USB adapter and RealTerm to read that data. It can be used to watch the communication between the software and the card. However the included firmware is UART-disabled. If anyone needs an UART-enabled firmware - just drop me a message.
I'm also working on a test-bb.exe diagnostic utility for the BlasterBoard right now, and it has software switching of UART mode without the need to reflash the MCU. But the utility is not ready yet.

One known issue is that the BlasterBoard do not pass the test-sbc.exe sample playback stage. This bothered me since the very beginning of development. Using UART mode I found out that it sends weird and undocumented 0xE2 command just before staring the playback. The problem is that this command should send its response back to the host in a DMA buffer(!). BlasterBoard's architecture does not support sample recording, so DMA transfer from the card to the host is not implemented in hardware and this single command cannot be done correctly. This command is so undocumented, that looks like test-sbc.exe is the only one using it, as all games and soft I tried work fine.

As there are lots of free cycles available in ATmega during PCM playback, some kind of upsampling algorithm could be implemented in firmware to increase 8-bit sample resolution and decrease quantization noise. The kit includes an 8-pin DIP socket for the DAC, so it could be changed to a better one (say 12-bit) if it is ever going to happen in future.

Last edited by LABS on 2019-07-09, 22:24. Edited 1 time in total.

BLASTERBOARD: a DIY SB2.0-compatible sound card on ATmega328P microcontroller

Reply 221 of 395, by root42

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Look what has arrived today:

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Prepare to be soldered!

Last edited by root42 on 2019-07-09, 12:38. Edited 1 time in total.

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Reply 223 of 395, by keropi

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I don't know if it's relevant but in "Alone in the Dark" setup there are 2 SoundBlaster 1x options: "non dma" and "dma"
Does the DMA option work OK?

cT89QGt.gif Amstrad PC7486SLC-33 wanted , click me for AmiBay ad!

Reply 224 of 395, by LABS

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keropi wrote:

I don't know if it's relevant but in "Alone in the Dark" setup there are 2 SoundBlaster 1x options: "non dma" and "dma"
Does the DMA option work OK?

Its not relevant, AITD doesn't use 0xE2 command, nor does any other games/software/SB windows drivers/directx I tested the BB with, only the test-sbc.exe...

BLASTERBOARD: a DIY SB2.0-compatible sound card on ATmega328P microcontroller

Reply 225 of 395, by Eleanor1967

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Mine also arrived today. The kit looks superb, the manual is a real nice touch! I thought about socketing all the chips, are there any chips were this isn't recommended?

Reply 226 of 395, by root42

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Eleanor1967 wrote:

Mine also arrived today. The kit looks superb, the manual is a real nice touch! I thought about socketing all the chips, are there any chips were this isn't recommended?

I started off doing that in the early days, because I wasn't confident not to destroy the ICs. But for the Blasterboard I would only socket the OPL2, the ATmega and the OPL2's DAC. Since the Yamaha ICs are old, they might be faulty or fail at some point (unlikely as that may be). But in any case they can be salvaged more easily that way. And the ATmega might want a firmware upgrade at some point. So socketing it allows you to easily reprogram it.

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Reply 227 of 395, by MJay99

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Since it just happened to be in the works over the last weeks and finally came up working again (cleaning from being stored in a seemingly humid and moldy environment for years, retrobrighting, kid's art, a PSU with the weirdest issues we ever saw, subsequent conversion to another PSU, an upgrade to a NEC V20 and a different BIOS today) the honors of its first power-up were this Commodore PC10-II's (which, of course, isn't gonna become its final home):

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For the moment and its limited cpu-power, it was just tested with an early Sierra game and old, but quite powerful speakers - but how impressive the result: no noticeable noise at all, even with the volume-knobs at maximum on both the card and the amplified speakers. Just... wow! From a purely subjective point of... listening: an awesome result! 😎

For the fun of it, I'll be visiting a colleague with an array of self-built (tube-)amps and speakers soon (since he's as much interested in retro hardware, also) just to see how things sound on much better audio-hardware than I have here. It's definitely not gonna be any objective testing, just the ears and comments of an audiophile colleague.

Reply 229 of 395, by LABS

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root42 wrote:
Eleanor1967 wrote:

Mine also arrived today. The kit looks superb, the manual is a real nice touch! I thought about socketing all the chips, are there any chips were this isn't recommended?

I started off doing that in the early days, because I wasn't confident not to destroy the ICs. But for the Blasterboard I would only socket the OPL2, the ATmega and the OPL2's DAC. Since the Yamaha ICs are old, they might be faulty or fail at some point (unlikely as that may be). But in any case they can be salvaged more easily that way. And the ATmega might want a firmware upgrade at some point. So socketing it allows you to easily reprogram it.

From my experience, OPL2 and it's DAC are rather tough, never had problems with them soldered/desoldered several times.
Avoid socketing opamps and use included DIP28 for ATmega for reflashing and DIP8 for Atmega's DAC for possible future upgrade (as it is already written in the manual). Socketing other ICs - at your discretion, it will not affect anything as circuit's frequences are not high.

BLASTERBOARD: a DIY SB2.0-compatible sound card on ATmega328P microcontroller

Reply 230 of 395, by dreamblaster

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My fully soldered LABS BLASTERBOARD arrived today,
and it looks great !! 😀
Thanks LABS !!

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Visit www.serdashop.com for retro sound cards, video converters, ...
OPL2LPT, OPL3LPT, X2, S2, S2P, MCE2VGA, ... many projects !
Special vogons LPT bundle : https://www.serdashop.com/Parallel-port ... und-bundle
Thanks for your support !

Reply 231 of 395, by root42

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Sneak preview:

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Reply 233 of 395, by root42

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Sure thing. Might take me until the weekend. Work and family will keep me busy. Also, I do want to do a bit of a comparison with the other cards. That will take a bit of time.

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Reply 235 of 395, by matze79

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It will take some time until i can build this 😀
i need to buy some IC Sockets first 😁

EDIT:
Made a backup of the DSP Chip, looks like there is plenty of space avaible 😉

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Reply 236 of 395, by LABS

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matze79 wrote:

Made a backup of the DSP Chip, looks like there is plenty of space avaible 😉

Exactly, a lot of space, cycles and unused SB commands are available, so additional functions like a softsynth or upsampling algorythm can be added.
And you can always ask me for a firmware image.

BLASTERBOARD: a DIY SB2.0-compatible sound card on ATmega328P microcontroller

Reply 238 of 395, by root42

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FreddyV wrote:

Hi,

Is it still possible to have it ?

To test my player with it 😀

Well, if nothing else I guess the new owners will test your software on it. Maybe not on an 8088 though.

Soldering, retro game reviews and more on YouTube and Bonus videos
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Reply 239 of 395, by MJay99

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root42 wrote:

Well, if nothing else I guess the new owners will test your software on it. Maybe not on an 8088 though.

Actually, that PC10 from above is an 8088 system 🤣