I finally found the problem! The platform_spi_init function has an optimization where it checks to see if the spi has already been initilaized
WICED/platform/MCU/STM32F4xx/peripherals/platform_spi.c line 180
if (spi_current_config[spi_number].bits == config->bits &&
spi_current_config[spi_number].cs.port == config->chip_select->port &&
spi_current_config[spi_number].cs.pin_number == config->chip_select->pin_number &&
spi_current_config[spi_number].mode == config->mode &&
spi_current_config[spi_number].speed == config->speed &&
spi_current_config[spi_number].spi == spi->port &&
spi_current_config[spi_number].spi_ready == WICED_TRUE)
return PLATFORM_SUCCESS;
What happens is the configuration is stored in spi_current_config structure and is compared to the config parameter and returns success if it's the same. When the system resets the values in api_current_config aren't reset and the system assumes that the spi bus has already been configured and doesn't properly enable the spi bus. So the system halts when the spi bus is accessed because it's not enabled.
The solution I came up with is to check that the SPI register has been enabled. The datasheet says the default value of the CR1 register is 0x0000 after a reboot.
if (spi_current_config[spi_number].bits == config->bits &&
spi_current_config[spi_number].cs.port == config->chip_select->port &&
spi_current_config[spi_number].cs.pin_number == config->chip_select->pin_number &&
spi_current_config[spi_number].mode == config->mode &&
spi_current_config[spi_number].speed == config->speed &&
spi_current_config[spi_number].spi == spi->port &&
spi_current_config[spi_number].spi_ready == WICED_TRUE &&
spi->port->CR1 != 0x0000)
return PLATFORM_SUCCESS;
This completely fixed the issue for me.
-Rob
