It has a Atmel ATmega8-16AC 0318 square chip on its joystick PCB. I can't figure out the com protocol for my speed controller. It came off a invacare wheelchair. I've called them, no help yet. The most likely port is defined as pin 2 is (could this be left right?) (manual says "communication bus high") pin 3 is (manual says "communication bus high") I know that pin 1 is + 24 volts, I know that pin 4 is - 24volts.
Could this be ic2, serial, serial transmit only?. Many wheelchairs you connect pin1 to ground=forward pin2 to ground=backward etc. But this system doesn't work on that protocol.
Thanks for any help.
wheelchair($100.00)(new4,795.00): Invacare Nutron R51 serial # 04D362619 Post 2/14/03
MK5 SPJController(1,102.50): DK-PMA01 MK 5 NX model # 1109530 connectors include "DCI" Ports
Joystick4 DCI4 motorA4 power2 motorB4
I probed around jumped pins to ground and to other pins. Nothing learned except that everything still works so very fault and polarity tolerant :)
Joystick pin 3 to ground did nothing 3 to 2 went high 24v?
on joystick 4 pin to controller on controller side positive light up high 24v? on all
other pins pin 3 to 2 jumped did nothing 4 to 2 and 3 did nothing
One guy from a competitor wheelchair manufacturer suggested that it was an inductive joystick so that I guess pin 2 is left right (manual says "communication bus high") pin 3 is forward back (manual says "communication bus high") I know that pin 1 is + I know that pin 2 is -
As a last resort I could go through the front of the joystick. That port is meant for rechargining and reprogramming. They claim that it is for serial data, but I don't see how as their is only one wire so that can't be serial transmit serial recieve. Don't you have to have 2 wires and ground to do serial communications? Fault log displays in 4 digit codes, 2 code and 2 as sub code. Is their any links for procedures on how to best hack electronic componenets. For example start probing around for serial data, then probe for ttl data, then probe for ic2 protocol data, then etc. Sort of reverse engineering I guess. PCB is 2003 "Dynamic Controls" https://www.invacare.com/product_files/1110532.pdf