diff options
| author | Keith Packard <keithp@keithp.com> | 2013-05-19 20:22:20 -0700 |
|---|---|---|
| committer | Keith Packard <keithp@keithp.com> | 2013-05-19 20:39:19 -0700 |
| commit | e383d7a28d01729c50f933ceda77ea767d1b8087 (patch) | |
| tree | d0bda7f5d7933ee75523e0db2158fb88daf58a6d /src/lpc/ao_spi_lpc.c | |
| parent | 07d261c08214837b5d5cac4d2be43e51a0c47868 (diff) | |
altos/lpc: Create TX/RX busy macros for SPI driver
Check for both fifo status *and* device busy to make sure the device
is idle before we touch any registers.
Signed-off-by: Keith Packard <keithp@keithp.com>
Diffstat (limited to 'src/lpc/ao_spi_lpc.c')
| -rw-r--r-- | src/lpc/ao_spi_lpc.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/src/lpc/ao_spi_lpc.c b/src/lpc/ao_spi_lpc.c index 05688f52..e7edca4c 100644 --- a/src/lpc/ao_spi_lpc.c +++ b/src/lpc/ao_spi_lpc.c @@ -23,21 +23,25 @@ static struct lpc_ssp * const ao_lpc_ssp[LPC_NUM_SPI] = { &lpc_ssp0, &lpc_ssp1 } static uint8_t spi_dev_null; +#define tx_busy(lpc_ssp) (lpc_ssp->sr & ((1 << LPC_SSP_SR_BSY) | (1 << LPC_SSP_SR_TNF))) != (1 << LPC_SSP_SR_TNF) +#define rx_busy(lpc_ssp) (lpc_ssp->sr & ((1 << LPC_SSP_SR_BSY) | (1 << LPC_SSP_SR_RNE))) != (1 << LPC_SSP_SR_RNE) + #define spi_loop(len, put, get) do { \ while (len--) { \ /* Wait for space in the fifo */ \ - while ((lpc_ssp->sr & (1 << LPC_SSP_SR_TNF)) == 0) \ + while (tx_busy(lpc_ssp)) \ ; \ + \ /* send a byte */ \ lpc_ssp->dr = put; \ \ + /* Wait for byte to appear in the fifo */ \ + while (rx_busy(lpc_ssp)) \ + ; \ + \ /* recv a byte */ \ get lpc_ssp->dr; \ } \ - \ - /* Wait for the fifo to drain */ \ - while ((lpc_ssp->sr & (1 << LPC_SSP_SR_BSY))) \ - ; \ } while (0); void |