TMCstepper - TMC2209 - 1 wire serial

[Alextrical]

Hi all

I'm looking to build a system to control the electronics for recycling plastic bottles into filament, the project can be found here Though I'm struggling to communicate with the TMC2209 driver, and could really use some help.

The issue I currently have is communicating with a TMC2209 via a 1 wire serial connection.

The board I'm trying to use is a BigTreeTech EBB42 v1.1
Schematic can be found here
Product link can be found here

The code I'm currently trying based on another post on this forum

#include <TMCStepper.h>           // TMCstepper - https://github.com/teemuatlut/TMCStepper

#define LED_PIN           PA13    // Visual feedback; onboard LED 
#define EN_PIN            PB5     // Enable pin
#define DRIVER_ADDRESS    0b00    // TMC2209 Driver address
#define R_SENSE           0.11f   // SilentStepStick series use 0.11
#define SW_RX             PA15    // TMC2208/TMC2224 SoftwareSerial receive pin
#define SW_TX             PA15    // TMC2208/TMC2224 SoftwareSerial transmit pin
//#define SERIAL_PORT       Serial  // TMC2208/TMC2224 HardwareSerial port

#define RMS_CURRENT       600     // Motor RMS current in mA
#define MICROSTEPS        8       // Microsteps; note that MicroPlyer will interpolate to 256
#define SPREADCYCLE       false   // Spreadcycle can have higher RPM but is louder

TMC2209Stepper driver(SW_RX, SW_TX, R_SENSE, DRIVER_ADDRESS);   // Create TMC driver

void setup() {
  pinMode(EN_PIN, OUTPUT);
  pinMode(LED_PIN, OUTPUT);

  //SERIAL_PORT.begin(115200);
  driver.beginSerial(115200);     // SW UART drivers

  digitalWrite(EN_PIN, LOW);            // Enable TMC2209 board

  driver.begin();
  driver.toff(5);                       // Enables driver in software
  driver.rms_current(RMS_CURRENT);      // Set motor RMS current (mA)
  driver.microsteps(MICROSTEPS);        // Set microsteps

  driver.en_spreadCycle(SPREADCYCLE);   // Toggle spreadCycle on TMC2208/2209/2224
  driver.pwm_autoscale(true);           // Needed for stealthChop
}

int32_t curr_speed = 0;
int32_t dest_speed = 1000 * MICROSTEPS;
int32_t acceleration = 10 * MICROSTEPS;

void ramp() {
  digitalWrite(LED_PIN, dest_speed > 0);
  while ((dest_speed > 0 && curr_speed < dest_speed) || (dest_speed < 0 && curr_speed > dest_speed)) {
    curr_speed += acceleration;
    driver.VACTUAL(curr_speed);
    delayMicroseconds(100);
  }
}

void loop() {
  ramp();
  delay(1000);
  dest_speed *= -1;
  acceleration *= -1;
}

Any help and pointers are greatly appreciated.

[Railroader]

@Alextrical

The issue

is?

[Alextrical]

The issue is using a single pin on the MCU to communicate with the STM2209 chip as configured on the commercially available board (that doesn't have a resistor across TX and RX)

In the images below, taken from the schematic, we can see that PDN_UART on the TMC2209 is connected to only PA15 on the MCU. Unfortunately I cant see how to proceed as this seems to be an edge case, and the built in software serial doesn't seem to be able to handle using a single IO for both send and recieve

Please let me know if there is anything I can further provide to clarify the issue.

[jonas_guo]

In this case, read access cannot be use