This programmer is connected via an asyncronous RS-232 port.
All ISP functions are controlled by the firmware. Therefore the
device support depends only on the firmware version.
The system load created by the driver for this programmer is low.
Therefore very old machines are sufficient to use it - even if they do
not have a fixed disk (Verified using a 286-10 machine with a 16550A
UART running DOS).
This programmer is itself based on an AVR, the AT90S2313. A TTL/RS232
level converter completes the hardware.
The target system VCC must be 5V (lower voltages my work if the RS-232
level converter can handle them).
A reset button should exist to resync the RS-232 communication in
the case of an error.
Get schematic from download page.
The protocol on the RS-232 line uses a bitrate of 38400b/s with a simple software handshake. Therefore a 3-wire cable can be used.
Note:
No polling and real paged memory support is implemented at the moment!
Do NOT use this programmer for ATmega series except you have enough
patience! It can be really slow. The ATmega devices are supported for
emergency only (if no other programmer is available).
The firmware is responsible for the device support.
Check the following list:
Note:
There is no mechanism for checking the firmware version via the
RS-232 cable.
Get firmware and RS-232 protocol docu from download page.