altos/stmf0: Have fast ADC ring buffer code use wrap-around

[fw/altos] / src / stmf0 / ao_adc_fast.c

diff --git a/src/stmf0/ao_adc_fast.c b/src/stmf0/ao_adc_fast.c
index 7d2a4fd7e005df9f684de464d3ef431d6326238e..26e6691c914c87169d72905dbcdfe06ea393cca1 100644 (file)
--- 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;