diff options
| author | Keith Packard <keithp@keithp.com> | 2015-02-28 15:59:30 -0800 |
|---|---|---|
| committer | Keith Packard <keithp@keithp.com> | 2015-02-28 16:10:10 -0800 |
| commit | 27aef593fb4c037fdb65c9fb397829b42d72d0f2 (patch) | |
| tree | 2f486084b10b616ed7b9d12bc949908c5dd7aedc /src/stmf0/ao_adc_fast.c | |
| parent | ec2d758844202108b446e6b12ec1da8812ceb265 (diff) | |
altos/stmf0: Fix fast ADC interface
This was configuring the hardware wrong, and wasn't keeping the output
ring full.
Signed-off-by: Keith Packard <keithp@keithp.com>
Diffstat (limited to 'src/stmf0/ao_adc_fast.c')
| -rw-r--r-- | src/stmf0/ao_adc_fast.c | 31 |
1 files changed, 20 insertions, 11 deletions
diff --git a/src/stmf0/ao_adc_fast.c b/src/stmf0/ao_adc_fast.c index be9b5986..7d2a4fd7 100644 --- a/src/stmf0/ao_adc_fast.c +++ b/src/stmf0/ao_adc_fast.c @@ -18,43 +18,52 @@ #include <ao.h> #include <ao_adc_fast.h> -uint16_t ao_adc_ring[AO_ADC_RING_SIZE]; +uint16_t ao_adc_ring[AO_ADC_RING_SIZE] __attribute__((aligned(4))); + +/* Maximum number of samples fetched per _ao_adc_start call */ +#define AO_ADC_RING_CHUNK (AO_ADC_RING_SIZE >> 1) uint16_t ao_adc_ring_head, ao_adc_ring_tail; -uint8_t ao_adc_running; +uint16_t ao_adc_running; /* * Callback from DMA ISR * - * Mark time in ring, shut down DMA engine + * Wakeup any waiting processes, mark the DMA as done, start the ADC + * if there's still lots of space in the ring */ static void ao_adc_dma_done(int index) { (void) index; - ao_adc_ring_head += AO_ADC_RING_CHUNK; + ao_adc_ring_head += ao_adc_running; if (ao_adc_ring_head == AO_ADC_RING_SIZE) ao_adc_ring_head = 0; ao_adc_running = 0; ao_wakeup(&ao_adc_ring_head); ao_dma_done_transfer(STM_DMA_INDEX(STM_DMA_CHANNEL_ADC_1)); + _ao_adc_start(); } void _ao_adc_start(void) { uint16_t *buf; + uint16_t count; if (ao_adc_running) return; - if (_ao_adc_space() < AO_ADC_RING_CHUNK) + count = _ao_adc_space(); + if (count == 0) return; - ao_adc_running = 1; + if (count > AO_ADC_RING_CHUNK) + count = AO_ADC_RING_CHUNK; + ao_adc_running = count; buf = ao_adc_ring + ao_adc_ring_head; stm_adc.isr = 0; ao_dma_set_transfer(STM_DMA_INDEX(STM_DMA_CHANNEL_ADC_1), &stm_adc.dr, buf, - AO_ADC_RING_CHUNK, + count, (0 << STM_DMA_CCR_MEM2MEM) | (STM_DMA_CCR_PL_HIGH << STM_DMA_CCR_PL) | (STM_DMA_CCR_MSIZE_16 << STM_DMA_CCR_MSIZE) | @@ -140,7 +149,6 @@ ao_adc_init(void) #if AO_NUM_ADC > 8 #error Need more ADC defines #endif - stm_adc.chselr = chselr; /* Set the clock */ stm_adc.cfgr2 = STM_ADC_CFGR2_CKMODE_PCLK_2 << STM_ADC_CFGR2_CKMODE; @@ -160,14 +168,16 @@ ao_adc_init(void) while ((stm_adc.isr & (1 << STM_ADC_ISR_ADRDY)) == 0) ; + stm_adc.chselr = chselr; + stm_adc.cfgr1 = ((0 << STM_ADC_CFGR1_AWDCH) | (0 << STM_ADC_CFGR1_AWDEN) | (0 << STM_ADC_CFGR1_AWDSGL) | (0 << STM_ADC_CFGR1_DISCEN) | (0 << STM_ADC_CFGR1_AUTOOFF) | - (1 << STM_ADC_CFGR1_WAIT) | + (0 << STM_ADC_CFGR1_WAIT) | (1 << STM_ADC_CFGR1_CONT) | - (0 << STM_ADC_CFGR1_OVRMOD) | + (1 << STM_ADC_CFGR1_OVRMOD) | (STM_ADC_CFGR1_EXTEN_DISABLE << STM_ADC_CFGR1_EXTEN) | (0 << STM_ADC_CFGR1_ALIGN) | (STM_ADC_CFGR1_RES_12 << STM_ADC_CFGR1_RES) | @@ -186,5 +196,4 @@ ao_adc_init(void) stm_syscfg.cfgr1 &= ~(1 << STM_SYSCFG_CFGR1_ADC_DMA_RMP); ao_dma_alloc(STM_DMA_INDEX(STM_DMA_CHANNEL_ADC_1)); - ao_dma_set_isr(STM_DMA_INDEX(STM_DMA_CHANNEL_ADC_1), ao_adc_dma_done); } |