diff options
| author | Keith Packard <keithp@keithp.com> | 2015-03-20 15:09:20 -0700 |
|---|---|---|
| committer | Keith Packard <keithp@keithp.com> | 2015-03-20 15:09:20 -0700 |
| commit | b1b69c8b73cbffb56c688f6a968d144b642cdff2 (patch) | |
| tree | e54eb4ccbed98014a6ccce31d6144b5a3e2866f1 /src/stmf0/ao_adc_fast.c | |
| parent | 43b4044dc71d44cb25be6397b4d66fd792580eed (diff) | |
altos/stmf0: Have fast ADC ring buffer code use wrap-around
Instead of requiring that the whole set of returned values fit
precisely in the ring, allow for wrap-around so that we can fetch an
odd number of ADC values. The previous version required that the fetch
amount always be a factor of the ADC buffer size.
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 | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/src/stmf0/ao_adc_fast.c b/src/stmf0/ao_adc_fast.c index 7d2a4fd7..26e6691c 100644 --- a/src/stmf0/ao_adc_fast.c +++ b/src/stmf0/ao_adc_fast.c @@ -23,7 +23,7 @@ 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; +uint16_t ao_adc_ring_head, ao_adc_ring_remain; uint16_t ao_adc_running; /* @@ -36,6 +36,7 @@ static void ao_adc_dma_done(int index) { (void) index; ao_adc_ring_head += ao_adc_running; + ao_adc_ring_remain += ao_adc_running; if (ao_adc_ring_head == AO_ADC_RING_SIZE) ao_adc_ring_head = 0; ao_adc_running = 0; |