First post, by Darmok
- Rank
- Newbie
Serial mice have a low number of reports per second, which is due to the low transfer speed of the RS232 interface. The standard value for mice is 1200 baud, while we have 40 reports per second for a mouse in the MS Mouse standard. This may not be enough for dynamic shooters. If you increase the transfer speed to, for example, 4800 baud, we get 160 reports per second, which is already quite acceptable. Experiments show that further increasing the number of reports per second for a serial mouse does not bring real benefit, but on the contrary, due to the increase in the number of interrupts per second, overall performance may deteriorate.
The controllers of many serial mice use a timing quartz resonator with a frequency of 32768 Hz. In most cases, the controller is able to work with a resonator of 131072 Hz, and the exchange rate via the interface will proportionally increase to 4800 baud.
The Genius EasyMouse serial ball mouse with the Genius K0303028 controller was used as an experimental sample. I replaced the 32768 Hz resonator with a similar resonator (in a cylindrical case) with a frequency of 131072 Hz. Modified Microsoft mouse drivers were used to test the mouse. Re: USB to Serial Mouse using the Pi Pico!
The computer used for testing was 386DX40, DOS and Win95. Mouse movements became smoother and more responsive. For illustration purposes, I provide files obtained in the Paint editor from Win95. I moved the mouse with my hand at about the same speed.
Since this method of overclocking is very easy to implement, anyone can repeat it and evaluate its usefulness for themselves.
