Because the CC2538 has a multi-byte SPI RX FIFO, flushing the buffer
requires more than just a single read. This adds a loop that empties the
entire RX buffer on a FLUSH().
Different SPI chips needs different SPI settings. This commit adds a
function that allows chip drivers to configure the SPI peripheral before
using it.
The frame pin the driver was using as a chip select does not work as
most devices expect it to. It toggles after every byte, and most chips
interpret that as end of message. To make drivers more reliable, each
chip driver should setup a GPIO and assert it as needed.
Homogenize port and pin definitions naming:
- PERIPHERAL_FUNCTION_PORT for the port ID,
- PERIPHERAL_FUNCTION_PIN for the pin ID,
- PERIPHERAL_FUNCTION_PORT_BASE for the port base,
- PERIPHERAL_FUNCTION_PIN_MASK for the pin mask.
Define only PERIPHERAL_FUNCTION_PORT and PERIPHERAL_FUNCTION_PIN in board.h, and
deduce PERIPHERAL_FUNCTION_PORT_BASE and PERIPHERAL_FUNCTION_PIN_MASK in the
driver from the former definitions.
Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
spi-arch.h configures dev/spi.h, so it must be #included first. Luckily, this
mistake did not have any consequence here, but fix it in order to avoid possible
future issues.
Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
If the SSI has never been used and spi_init() is called, then the SSI receive
FIFO is empty and remains so, so calling SPI_WAITFOREORx() at the end of
spi_init() waits endlessly for SSI_SR.RNE to be set. Hence, this call must be
removed in order to avoid a deadlock.
Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
This uses the core/dev/spi.h header and implements the spi_init()
function and the various macros for SPI operation. ssi.h contains all of
the register locations and information.
This implementation is not very versatile, mostly because I don't how to
make it flexible in the contiki system. It supports pin muxing for the
four spi pins, but other than that picks sensible defaults.
The SPI macros (like SPI_READ()) are defined in
cpu/cc2538/spi-arch.h. In order to use the SPI driver, add the following
includes to your project:
#include "spi-arch.h
#include "dev/spi.h"
