creapunk
CLN17 v1.5 PCB design issue
For CLN17 v1.5 PCB, there is an error with the design between STM32 PB_10/PB_11 pins and TMC2209 PDN. Currently there is a 501ohm resistor between these pins which prevents the uart signal from STM32 from getting to the TMC2209 driver - leading to TMC2209 inability to control current and smaller NEMA17 motors get really hot and would burn out.
A workaround is to solder across where the resistor should be, thus allowing unidirectional uart to TMC2209. In order to have bidirectional UART communication to TMC2209, there needs to be a 1k resistor between PB_10 and PB_11, according to TMC2209 spec sheet.
CLN17-V1.5-SCH.pdf doesn't show any resistor between PB_10 and PB_11. Was expecting resistor between them and only RX is direct to TMC2209 PDN. Guessing this is low pri to fix since looks like V2.0 doesn't use TMC2209 any more.
Also, not sure why, but have seen Maslow 4 PCB use 1.5k instead of the commonly used 1k between MCU pins used for UART TX and RX that TMC2209 datasheet spec section 4.3 recommends. Mentioning incase someone has informed views on reason(s) to deviate from datasheet and use 1.5k instead of 1k.
