SPI encoder with CS_N on GPIO2 issue

Support ODrive v3 Support
1

Hello,

I have 2 SPI encoders connected to my ODrive v3.6. First encoder is has the CS_N on the GPIO1 and it works fine. The other one has CS_N on GPIO2, however the chip select doesn’t work. I’m aware that on the GPIO1 and 2 there is the UART_A, I disabled it. Is there anything else that could prevent the GPIO2 to work properly?

odrive config:

brake_resistance: 0.4699999988079071 (float)
dc_bus_overvoltage_ramp_end: 25.68000030517578 (float)
dc_bus_overvoltage_ramp_start: 25.68000030517578 (float)
dc_bus_overvoltage_trip_level: 25.68000030517578 (float)
dc_bus_undervoltage_trip_level: 8.0 (float)
dc_max_negative_current: -1.0 (float)
dc_max_positive_current: inf (float)
enable_brake_resistor: False (bool)
enable_can_a: True (bool)
enable_dc_bus_overvoltage_ramp: False (bool)
enable_i2c_a: False (bool)
enable_uart_a: False (bool)
enable_uart_b: False (bool)
enable_uart_c: False (bool)
error_gpio_pin: 0 (uint32)
gpio10_mode: 11 (uint8)
gpio11_mode: 2 (uint8)
gpio12_mode: 12 (uint8)
gpio13_mode: 12 (uint8)
gpio14_mode: 2 (uint8)
gpio15_mode: 7 (uint8)
gpio16_mode: 7 (uint8)
gpio1_mode: 0 (uint8)
gpio1_pwm_mapping:
  endpoint: None (object_ref)
  max: 0.0 (float)
  min: 0.0 (float)
gpio2_mode: 0 (uint8)
gpio2_pwm_mapping:
  endpoint: None (object_ref)
  max: 0.0 (float)
  min: 0.0 (float)
gpio3_analog_mapping:
  endpoint: None (object_ref)
  max: 0.0 (float)
  min: 0.0 (float)
gpio3_mode: 3 (uint8)
gpio3_pwm_mapping:
  endpoint: None (object_ref)
  max: 0.0 (float)
  min: 0.0 (float)
gpio4_analog_mapping:
  endpoint: None (object_ref)
  max: 0.0 (float)
  min: 0.0 (float)
gpio4_mode: 3 (uint8)
gpio4_pwm_mapping:
  endpoint: None (object_ref)
  max: 0.0 (float)
  min: 0.0 (float)
gpio5_mode: 3 (uint8)
gpio6_mode: 0 (uint8)
gpio7_mode: 0 (uint8)
gpio8_mode: 0 (uint8)
gpio9_mode: 11 (uint8)
max_regen_current: 1.0 (float)
uart0_protocol: 3 (uint8)
uart1_protocol: 3 (uint8)
uart2_protocol: 3 (uint8)
uart_a_baudrate: 115200 (uint32)
uart_b_baudrate: 115200 (uint32)
uart_c_baudrate: 115200 (uint32)
usb_cdc_protocol: 3 (uint8)

encoder config:

abs_spi_cs_gpio_pin: 2 (uint16)
bandwidth: 1000.0 (float)
calib_range: 0.019999999552965164 (float)
calib_scan_distance: 50.26548385620117 (float)
calib_scan_omega: 12.566370964050293 (float)
cpr: 16384 (int32)
direction: 0 (int32)
enable_phase_interpolation: True (bool)
find_idx_on_lockin_only: False (bool)
hall_polarity: 0 (uint8)
hall_polarity_calibrated: False (bool)
ignore_illegal_hall_state: False (bool)
index_offset: 0.0 (float)
mode: 257 (uint16)
phase_offset: 0 (int32)
phase_offset_float: 0.0 (float)
pre_calibrated: False (bool)
sincos_gpio_pin_cos: 4 (uint16)
sincos_gpio_pin_sin: 3 (uint16)
use_index: False (bool)
use_index_offset: True (bool)

Thanks

2

Hmm, what actual error are you getting?

3

I get the ABS_SPI_COM_FAIL. Which makes sense, as on the scope I can see the CS_N on the GPIO2 is not going low.

4

Interesting – can you switch that to another GPIO pin and try?

5

Oh yes I forgot to mention that, if I set one on GPIO1 and the other on GPIO3 it works fine

6

Probably some weird interplay with the UART stuff – is there an issue with using GPIO1/GPIO3 like that?

7

Ideally I could solve it, but I can botch the PCB to which my ODrive is interfacing. Now I have a neat direct pin header connection.

8

Ah, understood. Happy to check later, but yeah I’d say it’s probably not worth your time to dig into it, if you can bodge the PCB.