diff options
Diffstat (limited to 'center_fw/adc.c')
| -rw-r--r-- | center_fw/adc.c | 53 |
1 files changed, 41 insertions, 12 deletions
diff --git a/center_fw/adc.c b/center_fw/adc.c index eb5d4b5..0fb8251 100644 --- a/center_fw/adc.c +++ b/center_fw/adc.c @@ -78,7 +78,7 @@ void adc_configure_scope_mode(uint8_t channel_mask, int sampling_interval_ns) { } /* Regular operation receiver mode */ -void adc_configure_monitor_mode(struct command_if_def *cmd_if, int ivl_us) { +void adc_configure_monitor_mode(const struct command_if_def *cmd_if, int ivl_us) { /* First, disable trigger timer, DMA and ADC in case we're reconfiguring on the fly. */ TIM1->CR1 &= ~TIM_CR1_CEN; ADC1->CR &= ~ADC_CR_ADSTART; @@ -168,6 +168,11 @@ static void adc_timer_init(int psc, int ivl) { static void gdb_dump(void) { } +/* Called on reception of a bit. This feeds the bit to the 8b10b state machine. When the 8b10b state machine recognizes + * a received symbol, this in turn calls receive_symbol. Since this is called at sampling time roughly halfway into a + * bit being received, receive_symbol is called roughly half-way through the last bit of the symbol, just before the + * symbol's end. + */ void receive_bit(struct bit_detector_st *st, int bit) { int symbol = xfr_8b10b_feed_bit((struct state_8b10b_dec *)&st->rx8b10b, bit); if (symbol == -K28_1) @@ -180,9 +185,9 @@ void receive_bit(struct bit_detector_st *st, int bit) { st->sync = 0; /* Fall through so we also pass the error to receive_symbol */ - GPIOA->BSRR = 1<<9; + GPIOA->BSRR = 1<<9; /* debug */ receive_symbol(&st->rx_st, symbol); - GPIOA->BRR = 1<<9; + GPIOA->BRR = 1<<9; /* debug */ /* Debug scope logic */ /* @@ -205,23 +210,43 @@ void receive_bit(struct bit_detector_st *st, int bit) { */ } +/* From a series of detected line levels, extract discrete bits. This self-synchronizes to signal transitions. This + * expects base_interval_cycles to be set correctly. When a bit is detected, this calls receive_bit(st, bit). The call + * to receive_bit happens at the sampling point about half-way through the bit being received. + */ void bit_detector(struct bit_detector_st *st, int a) { int new_bit = st->last_bit; - int diff = a-5500; + int diff = a-5500; /* FIXME extract constants */ if (diff < - st->hysteresis_mv/2) new_bit = 0; else if (diff > st->hysteresis_mv/2) new_bit = 1; else - blank(); + blank(); /* Safety, in case we get an unexpected transition */ st->len_ctr++; - if (new_bit != st->last_bit) { + if (new_bit != st->last_bit) { /* On transition */ st->last_bit = new_bit; st->len_ctr = 0; - st->committed_len_ctr = st->base_interval_cycles>>1; + st->committed_len_ctr = st->base_interval_cycles>>1; /* Commit first half of bit */ } else if (st->len_ctr >= st->committed_len_ctr) { + /* The line stayed constant for a longer interval than the commited length. Interpret this as a transmitted bit. + * + * +-- Master clock edges -->| - - - - |<-- One bit period + * | | | + * 1 X X X X X X X X + * ____/^^^^*^^^^\_______________________________________/^^^^*^^^^^^^^^*^^^^\__________________________________ + * 0 v ^ v ^ + * | | | | + * | +-------------------------------+ +---------+ + * | | | + * At this point, commit 1/2 bit (until here). This When we arrive at the committed value, commit next + * happens in the block above. full bit as we're now right in the middle of the + * first bit. This happens in the line below. + */ + + /* Commit second half of this and first half of possible next bit */ st->committed_len_ctr += st->base_interval_cycles; receive_bit(st, st->last_bit); } @@ -238,24 +263,28 @@ void DMA1_Channel1_IRQHandler(void) { if (st.adc_mode == ADC_SCOPE) return; + /* FIXME This code section currently is a mess since I left it as soon as it worked. Re-work this and try to get + * back all the useful monitoring stuff, in particular temperature. */ + /* This has been copied from the code examples to section 12.9 ADC>"Temperature sensor and internal reference * voltage" in the reference manual with the extension that we actually measure the supply voltage instead of * hardcoding it. This is not strictly necessary since we're running off a bored little LDO but it's free and * the current supply voltage is a nice health value. */ - // FIXME DEBUG adc_data.adc_vcc_mv = (3300 * VREFINT_CAL)/(st.adc_aggregate[VREF_CH]); + // FIXME DEBUG adc_data.vcc_mv = (3300 * VREFINT_CAL)/(st.adc_aggregate[VREF_CH]); int64_t vcc = 3300; /* FIXME debug - int64_t vcc = adc_data.adc_vcc_mv; + int64_t vcc = adc_data.vcc_mv; int64_t read = st.adc_aggregate[TEMP_CH] * 10 * 10000; int64_t cal = TS_CAL1 * 10 * 10000; - adc_data.adc_temp_celsius_tenths = 300 + ((read/4096 * vcc) - (cal/4096 * 3300))/43000; + adc_data.temp_celsius_tenths = 300 + ((read/4096 * vcc) - (cal/4096 * 3300))/43000; */ + /* Calculate the line voltage from the measured ADC voltage and the used resistive divider ratio */ const long vmeas_r_total = VMEAS_R_HIGH + VMEAS_R_LOW; - //int a = adc_data.adc_vmeas_a_mv = (st.adc_aggregate[VMEAS_A]*(vmeas_r_total * vcc / VMEAS_R_LOW)) >> 12; - int a = adc_data.adc_vmeas_a_mv = (adc_buf[VMEAS_A]*13300) >> 12; + //int a = adc_data.vmeas_a_mv = (st.adc_aggregate[VMEAS_A]*(vmeas_r_total * vcc / VMEAS_R_LOW)) >> 12; + int a = adc_data.vmeas_a_mv = (adc_buf[VMEAS_A]*13300) >> 12; bit_detector((struct bit_detector_st *)&st.det_st, a); /* ISR timing measurement for debugging */ |