UART with EXT pins on Thingy:52 ?

[ragnarolsson]

Hey, i have got UART work on my Thingy52 with ANA/DIG0 and ANA/DIG1 as receiver and transmitter but when I am trying to use EXT0 and EXT1 as receiver and transmitter it doesn’t work.

This was how the code looked like when using EXT0 and EXT as receiver and transmitter :

const app_uart_comm_params_t comm_params =
{
SX_IOEXT_0,
SX_IOEXT_1,
MOS_1,
MOS_2,
APP_UART_FLOW_CONTROL_DISABLED,
false,
UART_BAUDRATE_BAUDRATE_Baud9600
};

And this is how the code looked like when i used ANA/DIG0 and ANA/DIG1 as receiver and transmitter :

const app_uart_comm_params_t comm_params =
{
ANA_DIG1,
ANA_DIG2,
MOS_1,
MOS_2,
APP_UART_FLOW_CONTROL_DISABLED,
false,
UART_BAUDRATE_BAUDRATE_Baud9600
};

Anyone that know if Is it not possible to use the EXT0 and EXT1 pins for UART or is it required to do some additional setup?

[Jørgen Holmefjord]

Hi,

EXT0 and EXT1 pins are connected to I/O expander IC that is controlled through I2C/TWI, it is not intended for use directly with internal peripherals. Could you possibly re-arrange your pin mapping to control some simpler device with the I/O expander, and use internal GPIOs for UART connection?

Best regards,
Jørgen

[Jørgen Holmefjord]

Looks like that could be hard to do, especially if you need UART and SPI at the same time. You can reconfigure the GPIOs between UART and SPI if that is an option, and use a pin on the I/O expander for SPI CS, and use the state of this pin to also tri-state the UART lines on the other end of the lines. This depends on your requirements, switching to a TWI/I2C based device would probably be a much simpler solution.

[ragnarolsson]

Thanks again, then i now what my option are.