Serial Mouse Converter
======================
This makes old serial mouse into modern USB one.
Tested by:
- Microsoft green-eyed mouse
- DELL mouse can work with DTR only.
Pinout
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DE-9 DB-25 DTE DCE Description
----------------------------------------------------------------
2 3 RXD TXD data from mouse
3 2 TXD RXD used by mouse as power source?
4 20 DTR DSR used by mouse as power source
5 7 GND GND
7 4 RTS CTS used by mouse as power source
*DTE=Converter, DCE=Mouse
## RS-232 Driver
Microsoft mouse seems to need higher voltage for power source.
SP3232E outputs only +-6V at charge pump output and didn't work.
ADM232A works for both Microsoft and DELL.
Microsoft green-eyed mouse requires both while DELL mouse can work with DTR only.
## Wiring
Mouse RXD, TXD, DTR and RTS should be wired to RS-232 driver.
Wire up RS-232 driver charge pump output V+ to DTR and RTS for power source purpose.
Connect Mouse TXD to AVR PD2(RXD) *through* RS-232 driver for mouse data.
UART Setting
------------
defined in config.h.
### Microsoft serial mouse
1200 baud, 7-bit data, no parity, 1-bit stop, lsb-first
### MouseSystems
1200 baud, 8-bit data, no parity, 1-bit stop, lsb-first(Not tested)
Resources
---------
Get power out of PC RS-232 port:
https://www.epanorama.net/circuits/rspower.html
Microsoft serial mouse:
https://web.archive.org/web/20130307230349/www.kryslix.com/nsfaq/Q.12.html
Serial Mice Protocols:
https://roborooter.com/post/serial-mice/
