Notes on reverse engineering efforts for the NeoDen 3 TM245P Pick and Place machine.

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$Morgan 'ARR\!' Allen$ Morgan 'ARR\!' Allen fe4a4a99b2 add bypass caps for transceivers		2024-02-20 08:55:25 -08:00
bus_splitter	add bypass caps for transceivers	2024-02-20 08:55:25 -08:00
data	some data dumped from the ds1052 scope	2022-09-07 11:06:45 -07:00
eevblog_teardown	notes dump	2022-09-01 14:26:58 -07:00
images	scope trace of bit	2022-09-05 22:47:50 -07:00
schematics	more schematic labeling	2022-09-05 23:19:53 -07:00
README.md	note on bus_splitter	2024-02-20 08:50:32 -08:00

README.md

RE-TM245P

The end goal of this project is to convert a partially broken TM245P Pick and Place to OpenPNP while replacing as little hardware as possible. The difficulty in this is that the feeders and everything on the head are CAN bus controlled. In an effort to not replace these parts, the protocol will need to be reverse engineered.

Approaches

Smoothieware Port

The Charmhigh conversion undertaken by others approaches leaving the controller largely intact and flashing a Smoothieware port onto the STM32. The repo notes suggest the Charmhigh used an STM32F4, which the TM245P also uses. Specifcally the STM32F407ZGT6.

https://github.com/mattthebaker/Smoothieware-CHMT

'Decap'

In this approach the entire head unit will be bypassed. Ideally this could be accomplished by utilizing the existing IDC connector on the power/comm sub-board.

'CAN Bus'

Communication is done over the VP230 CAN Transceiver, though it doesn't look to be real CAN. Instead the STM32 USART1 is connected so it's doing Syncronous UART over CAN. So it's really just using the VP230 for differential signaling.

What's Done

Schematic of STM32 <-> VP230 (CAN Bus)
Verified STM32 read protection is in place :(

Bus Splitter

The bus_splitter directory contains a KiCAD project to attempt reverse engineering the protocol 'monkey-in-the-middle' style. It contains two CAN bus transceivers, with the UART in between them being passed to a set of header pins. The idea being the RX/TX pins can be attached to an external microcontroller, allowing message to be inspected, modified and/or passed through as is.