diff options
Diffstat (limited to 'src/sensor_ads1220.c')
| -rw-r--r-- | src/sensor_ads1220.c | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/src/sensor_ads1220.c b/src/sensor_ads1220.c new file mode 100644 index 00000000..044980c7 --- /dev/null +++ b/src/sensor_ads1220.c @@ -0,0 +1,161 @@ +// Support for ADS1220 ADC Chip +// +// Copyright (C) 2024 Gareth Farrington <gareth@waves.ky> +// +// This file may be distributed under the terms of the GNU GPLv3 license. + +#include "board/irq.h" // irq_disable +#include "board/gpio.h" // gpio_out_write +#include "board/misc.h" // timer_read_time +#include "basecmd.h" // oid_alloc +#include "command.h" // DECL_COMMAND +#include "sched.h" // sched_add_timer +#include "sensor_bulk.h" // sensor_bulk_report +#include "spicmds.h" // spidev_transfer +#include <stdint.h> + +struct ads1220_adc { + struct timer timer; + uint32_t rest_ticks; + struct gpio_in data_ready; + struct spidev_s *spi; + uint8_t pending_flag, data_count; + struct sensor_bulk sb; +}; + +// Flag types +enum { + FLAG_PENDING = 1 << 0 +}; + +#define BYTES_PER_SAMPLE 4 + +static struct task_wake wake_ads1220; + +/**************************************************************** + * ADS1220 Sensor Support + ****************************************************************/ + +int8_t +ads1220_is_data_ready(struct ads1220_adc *ads1220) { + return gpio_in_read(ads1220->data_ready) == 0; +} + +// Event handler that wakes wake_ads1220() periodically +static uint_fast8_t +ads1220_event(struct timer *timer) +{ + struct ads1220_adc *ads1220 = container_of(timer, struct ads1220_adc, + timer); + uint32_t rest_ticks = ads1220->rest_ticks; + if (ads1220->pending_flag) { + ads1220->sb.possible_overflows++; + rest_ticks *= 4; + } else if (ads1220_is_data_ready(ads1220)) { + ads1220->pending_flag = 1; + sched_wake_task(&wake_ads1220); + rest_ticks *= 8; + } + ads1220->timer.waketime += rest_ticks; + return SF_RESCHEDULE; +} + +// Add a measurement to the buffer +static void +add_sample(struct ads1220_adc *ads1220, uint8_t oid, uint_fast32_t counts) +{ + ads1220->sb.data[ads1220->sb.data_count] = counts; + ads1220->sb.data[ads1220->sb.data_count + 1] = counts >> 8; + ads1220->sb.data[ads1220->sb.data_count + 2] = counts >> 16; + ads1220->sb.data[ads1220->sb.data_count + 3] = counts >> 24; + ads1220->sb.data_count += BYTES_PER_SAMPLE; + + if ((ads1220->sb.data_count + BYTES_PER_SAMPLE) > + ARRAY_SIZE(ads1220->sb.data)) { + sensor_bulk_report(&ads1220->sb, oid); + } +} + +// ADS1220 ADC query +void +ads1220_read_adc(struct ads1220_adc *ads1220, uint8_t oid) +{ + uint8_t msg[3] = {0, 0, 0}; + spidev_transfer(ads1220->spi, 1, sizeof(msg), msg); + ads1220->pending_flag = 0; + barrier(); + + // create 24 bit int from bytes + int32_t counts = (msg[0] << 16) | (msg[1] << 8) | msg[2]; + + // extend 2's complement 24 bits to 32bits + if (counts & 0x800000) + counts |= 0xFF000000; + + add_sample(ads1220, oid, counts); +} + +// Create an ads1220 sensor +void +command_config_ads1220(uint32_t *args) +{ + struct ads1220_adc *ads1220 = oid_alloc(args[0] + , command_config_ads1220, sizeof(*ads1220)); + ads1220->timer.func = ads1220_event; + ads1220->pending_flag = 0; + ads1220->spi = spidev_oid_lookup(args[1]); + ads1220->data_ready = gpio_in_setup(args[2], 0); +} +DECL_COMMAND(command_config_ads1220, "config_ads1220 oid=%c" + " spi_oid=%c data_ready_pin=%u"); + +// start/stop capturing ADC data +void +command_query_ads1220(uint32_t *args) +{ + uint8_t oid = args[0]; + struct ads1220_adc *ads1220 = oid_lookup(oid, command_config_ads1220); + sched_del_timer(&ads1220->timer); + ads1220->pending_flag = 0; + ads1220->rest_ticks = args[1]; + if (!ads1220->rest_ticks) { + // End measurements + return; + } + // Start new measurements + sensor_bulk_reset(&ads1220->sb); + irq_disable(); + ads1220->timer.waketime = timer_read_time() + ads1220->rest_ticks; + sched_add_timer(&ads1220->timer); + irq_enable(); +} +DECL_COMMAND(command_query_ads1220, "query_ads1220 oid=%c rest_ticks=%u"); + +void +command_query_ads1220_status(const uint32_t *args) +{ + uint8_t oid = args[0]; + struct ads1220_adc *ads1220 = oid_lookup(oid, command_config_ads1220); + irq_disable(); + const uint32_t start_t = timer_read_time(); + uint8_t is_data_ready = ads1220_is_data_ready(ads1220); + irq_enable(); + uint8_t pending_bytes = is_data_ready ? BYTES_PER_SAMPLE : 0; + sensor_bulk_status(&ads1220->sb, oid, start_t, 0, pending_bytes); +} +DECL_COMMAND(command_query_ads1220_status, "query_ads1220_status oid=%c"); + +// Background task that performs measurements +void +ads1220_capture_task(void) +{ + if (!sched_check_wake(&wake_ads1220)) + return; + uint8_t oid; + struct ads1220_adc *ads1220; + foreach_oid(oid, ads1220, command_config_ads1220) { + if (ads1220->pending_flag) + ads1220_read_adc(ads1220, oid); + } +} +DECL_TASK(ads1220_capture_task); |