diff options
| author | Keith Packard <keithp@keithp.com> | 2013-06-15 01:20:49 -0700 |
|---|---|---|
| committer | Keith Packard <keithp@keithp.com> | 2013-06-15 01:21:45 -0700 |
| commit | be9ee9ed2d041c4ab4e77ee2010fe3c7a1ca6597 (patch) | |
| tree | 2ec07a0e0e03157589b51e6d5d67a2e01972af83 /src/lpc/ao_adc_lpc.c | |
| parent | 7361371190bf3805b6d0414e61f697aca7c7cff1 (diff) | |
altos/lpc: Filter ADC inputs
They're amazingly noisy on EasyMini, so just filter them as the only
thing we use them for is battery and pyro numbers.
Signed-off-by: Keith Packard <keithp@keithp.com>
Diffstat (limited to 'src/lpc/ao_adc_lpc.c')
| -rw-r--r-- | src/lpc/ao_adc_lpc.c | 39 |
1 files changed, 25 insertions, 14 deletions
diff --git a/src/lpc/ao_adc_lpc.c b/src/lpc/ao_adc_lpc.c index 25a121b5..40173aa4 100644 --- a/src/lpc/ao_adc_lpc.c +++ b/src/lpc/ao_adc_lpc.c @@ -91,47 +91,58 @@ (AO_ADC_6 << 6) | \ (AO_ADC_7 << 7)) -#define AO_ADC_CLKDIV (AO_LPC_SYSCLK / 4500000 - 1) +#define AO_ADC_CLKDIV (AO_LPC_SYSCLK / 4500000) -static uint8_t ao_adc_ready; +static uint8_t ao_adc_ready; + +static uint16_t ao_adc_prev[AO_NUM_ADC]; + +#define sample(id) do { \ + uint16_t p = *prev; \ + uint16_t v = lpc_adc.dr[id]; \ + p -= p >> 4; \ + p += v >> 4; \ + *prev++ = p; \ + *out++ = p >> 1; \ + } while (0) void lpc_adc_isr(void) { uint32_t stat = lpc_adc.stat; uint16_t *out; + uint16_t *prev; - lpc_adc.cr = ((AO_ADC_MASK << LPC_ADC_CR_SEL) | - (AO_ADC_CLKDIV << LPC_ADC_CR_CLKDIV) | - (0 << LPC_ADC_CR_BURST) | - (LPC_ADC_CR_CLKS_11 << LPC_ADC_CR_CLKS)); + /* Turn off burst mode */ + lpc_adc.cr = 0; lpc_adc.stat = 0; /* Store converted values in packet */ out = (uint16_t *) &ao_data_ring[ao_data_head].adc; + prev = ao_adc_prev; #if AO_ADC_0 - *out++ = lpc_adc.dr[0] >> 1; + sample(0); #endif #if AO_ADC_1 - *out++ = lpc_adc.dr[1] >> 1; + sample(1); #endif #if AO_ADC_2 - *out++ = lpc_adc.dr[2] >> 1; + sample(2); #endif #if AO_ADC_3 - *out++ = lpc_adc.dr[3] >> 1; + sample(3); #endif #if AO_ADC_4 - *out++ = lpc_adc.dr[4] >> 1; + sample(4); #endif #if AO_ADC_5 - *out++ = lpc_adc.dr[5] >> 1; + sample(5); #endif #if AO_ADC_6 - *out++ = lpc_adc.dr[6] >> 1; + sample(6); #endif #if AO_ADC_7 - *out++ = lpc_adc.dr[7] >> 1; + sample(7); #endif AO_DATA_PRESENT(AO_DATA_ADC); |