Zephyr I2C Write Hangs

[amcelroy]

Howdy,

I'm using Zephyr to configure an nRF52840 to act as an I2C master and send data to a TM4C slave at a 100kHz clock rate. The nRF52840 appears to hang after calling i2c_transfer:

    char buffer = "B";
    struct i2c_msg msg;
    msg.buf = (u8_t *)buffer;
    msg.len = 1;
    msg.flags = I2C_MSG_WRITE | I2C_MSG_STOP;

    i2c_transfer(mdi_i2c_device, &msg, 1, I2C_ADDRESS);

Attached is an image of the logic analyzer trace of the SDA and SCL lines, as well as the analog traces. The address is submitted to the bus (1st red box), and the slave acknowledges it (first yellow box), and then the letter "B" is sent (2nd red box), and again the slave acknowledges it (2nd yellow box). The code never returns from i2c_transfer. I've tried changing the I2C_MSG_STOP to I2C_MSG_RESET, and i2c_transfer does return the first time, but not subsequent times.

Any advice would be appreciated!

Austin

[amcelroy]

Oh, my prj.conf file has the following:

#Flash

CONFIG_FLASH=y

CONFIG_MPU_ALLOW_FLASH_WRITE=y

#Bluetooth Configuration

CONFIG_BT=y

CONFIG_BT_DEBUG_LOG=y

CONFIG_BT_SMP=y

CONFIG_BT_SIGNING=y

CONFIG_BT_PERIPHERAL=y

CONFIG_BT_GATT_DIS=y

CONFIG_BT_ATT_PREPARE_COUNT=2

CONFIG_BT_PRIVACY=y

CONFIG_BT_DEVICE_NAME="Device Name"

CONFIG_BT_DEVICE_APPEARANCE=833

CONFIG_BT_DEVICE_NAME_DYNAMIC=y

CONFIG_BT_DEVICE_NAME_MAX=65

CONFIG_BT_SETTINGS=y

#CONFIG_BT_BONDABLE=y

#I2C

CONFIG_I2C=y

CONFIG_I2C_0=y

#Dynamic Memory Heap Size

CONFIG_HEAP_MEM_POOL_SIZE=1024

#Log Config

CONFIG_PRINTK=y

CONFIG_LOG=y

CONFIG_LOG_DEFAULT_LEVEL=4

CONFIG_LOG_MODE_OVERFLOW=y

CONFIG_LOG_PRINTK=y

#Segger Config

#CONFIG_CONSOLE=y

CONFIG_UART_CONSOLE=n

CONFIG_USE_SEGGER_RTT=y

CONFIG_RTT_CONSOLE=y

CONFIG_LOG_BACKEND_RTT=y

CONFIG_DEBUG_OPTIMIZATIONS=y

CONFIG_EXCEPTION_STACK_TRACE=y

CONFIG_DEBUG_INFO=y

#GPIO

CONFIG_GPIO=y

#UART Config

CONFIG_SERIAL=y

# CONFIG_UART_CONSOLE=n

#CONFIG_UART_INTERRUPT_DRIVEN=y

CONFIG_UART_ASYNC_API=y

#CONFIG_UART_ASYNC_API=y

#CONFIG_UART_0_INTERRUPT_DRIVEN=y

#CONFIG_UART_0_INTERRUPT_DRIVEN=y

#CONFIG_UART_0_ASYNC=y

#CONFIG_UART_NRF=y