1. Hoʻomau
ʻO ka papa kuhikuhi ka hana o ka hoʻomohala ʻana i kahi protocol kamaʻilio no ka microcontroller nrf52832 me ʻelua hapa-alahaka ʻāpana kānana Kina.
ʻAʻole maʻalahi ka hana, no ka mea, ua loaʻa iaʻu ka nele o ka ʻike maopopo. ʻOi aku paha ka "aʻa o ka hewa" i loko o ka SDK mai Nordic Semiconductor ponoʻī - hoʻomau mau ʻia nā mana hou, kekahi mau hana hou a huikau. Pono wau e kākau i nā mea a pau mai ka wā kahiko.
Manaʻo wau e pili pono ana kēia kumuhana ma muli o ka loaʻa ʻana o kēia puʻupuʻu BLE a me kahi pūʻulu o nā "maikaʻi" no ke ʻano mālama ola. Akā ʻaʻole wau e hele hohonu i ka ʻāpana ʻenehana, no ka mea, ua kākau ʻia nā ʻatikala he nui ma kēia kumuhana.
2. wehewehe papahana
hao:
- Adafruit Feather nRF52 Bluefruit LE (he aha ka mea i loaʻa ma ka lima)
- HX711 ADC
- 2 pcs. (50x2 kg)
- Mea papahana ST-LINK V2
palupalu:
- IDE VSCODE
- NRF SDK 16
- OpenOCD
- Mea papahana ST-LINK V2
Aia nā mea āpau i hoʻokahi papahana, pono ʻoe e hoʻololi i ka Makefile (e wehewehe i kahi o kāu SDK).
3. Ka wehewehe o ke code
E hoʻohana mākou i ka module GPIOTE e hana me nā peripheral e pili ana i ka hoʻopaʻa ʻana i nā hana a me nā hanana, a me ka module PPI e hoʻoili i ka ʻikepili mai kahi peripheral i kekahi me ke komo ʻole o kahi kaʻina hana.
ret_code_t err_code;
err_code = nrf_drv_gpiote_out_init(PD_SCK, &config);//настраеваем на выход
nrf_drv_gpiote_out_config_t config = GPIOTE_CONFIG_OUT_TASK_TOGGLE(false);//будем передергивать пин для импульса
err_code = nrf_drv_gpiote_out_init(PD_SCK, &config);//настраеваем на выход
Hoʻonohonoho mākou i ka laina hoʻonohonoho PD_SCL i ka hoʻopuka e hana i nā pulses me ka lōʻihi o 10 μs.
nrf_drv_gpiote_in_config_t gpiote_config = GPIOTE_CONFIG_IN_SENSE_HITOLO(false);// переход уровня с высокого на низкий
nrf_gpio_cfg_input(DOUT, NRF_GPIO_PIN_NOPULL);// на вход без подтяжки
err_code = nrf_drv_gpiote_in_init(DOUT, &gpiote_config, gpiote_evt_handler); static void gpiote_evt_handler(nrf_drv_gpiote_pin_t pin, nrf_gpiote_polarity_t action)
{
nrf_drv_gpiote_in_event_disable(DOUT);//отключаем прерывание
nrf_drv_timer_enable(&m_timer0);//включаем таймер
}
Hoʻonohonoho mākou i ka laina ʻikepili DOUT e heluhelu i ke kūlana mākaukau o ka HX711; inā he haʻahaʻa haʻahaʻa, hoʻāla ʻia kahi mea hoʻokele a mākou e hoʻopau ai i ka interrupt a hoʻomaka i kahi manawa e hoʻohua i nā pulses uaki ma ka puka PD_SCL.
err_code = nrf_drv_ppi_channel_alloc(&m_ppi_channel1);
APP_ERROR_CHECK(err_code);
err_code = nrf_drv_ppi_channel_assign(m_ppi_channel1, nrf_drv_timer_event_address_get(&m_timer0, NRF_TIMER_EVENT_COMPARE0), nrf_drv_gpiote_out_task_addr_get(PD_SCK));// подключаем таймер к выходу
APP_ERROR_CHECK(err_code);
err_code = nrf_drv_ppi_channel_enable(m_ppi_channel1);// включаем канал
APP_ERROR_CHECK(err_code);
nrf_drv_gpiote_out_task_enable(PD_SCK); // hiki iā gpiote
Ma hope o kēlā, hoʻomaka mākou i ka module PPI a hoʻohui i kā mākou manawa i ka PD_SCL output e hana i nā pulses me ka lōʻihi o 10 μs i ka wā e kū ai kahi hanana hoʻohālikelike, a hoʻohuli pū i ka module GPIOTE.
nrf_drv_timer_config_t timer_cfg = NRF_DRV_TIMER_DEFAULT_CONFIG;// по умолчанию
timer_cfg.frequency = NRF_TIMER_FREQ_1MHz;// тактируем на частоте 1Мгц
ret_code_t err_code = nrf_drv_timer_init(&m_timer0, &timer_cfg, timer0_event_handler);
APP_ERROR_CHECK(err_code);
nrf_drv_timer_extended_compare(&m_timer0,
NRF_TIMER_CC_CHANNEL0,
nrf_drv_timer_us_to_ticks(&m_timer0,
10),
NRF_TIMER_SHORT_COMPARE0_CLEAR_MASK,
true);// срабатывает по сравнениюHoʻomaka mākou i ka zero timer a me kāna mea lawelawe.
if(m_counter%2 != 0 && m_counter<=48){
buffer <<= 1;// переменная считанных даных
c_counter++;// счетчик положительных импульсов
if(nrf_gpio_pin_read(DOUT))buffer++;//считываем состояние входа
}
ʻO ka mea hoihoi loa e hana ʻia ma ka mea hoʻohana manawa. ʻO ka manawa pulse he 20 μs. Makemake mākou i nā puʻupuʻu ʻē aʻe (ma ka ʻaoʻao piʻi) a inā ʻaʻole i ʻoi aku ko lākou helu ma mua o 24, a he 48 mau hanana.
Mai ka ʻikepili e pili ana i ka helu o nā pulses ma kahi o 25, e pili ana i ka loaʻa ʻana o 128 (ma ke code aʻu i hoʻohana ai i 25 pulses), ua like kēia me 50 mau hanana manawa, e hōʻike ana i ka hopena o ka ʻikepili.
++m_counter;// счетчик событий
if(m_counter==50){
nrf_drv_timer_disable(&m_timer0);// отключаем таймер
m_simple_timer_state = SIMPLE_TIMER_STATE_STOPPED;//
buffer = buffer ^ 0x800000;
hx711_stop();//jотключаем hx711
}
Ma hope o kēia, hoʻopau mākou i ka manawa a hana i ka ʻikepili (e like me ka datasheet) a hoʻololi i ka HX711 i ke ʻano haʻahaʻa haʻahaʻa.
static void repeated_timer_handler(void * p_context)
{
nrf_drv_gpiote_out_toggle(LED_2);
if(m_simple_timer_state == SIMPLE_TIMER_STATE_STOPPED){
hx711_start();// включаем hx711
nrf_drv_gpiote_out_toggle(LED_1);
m_simple_timer_state = SIMPLE_TIMER_STATE_STARTED;
}
}
/**@brief Create timers.
*/
static void create_timers()
{
ret_code_t err_code;
// Create timers
err_code = app_timer_create(&m_repeated_timer_id,
APP_TIMER_MODE_REPEATED,
repeated_timer_handler);
APP_ERROR_CHECK(err_code);
}
Manaʻo mākou i nā hanana mai ka manawa RTC me kahi manawa o 10 s (ʻo ia ma kou manaʻo) a hoʻomaka i ka HX711 i ka mea hoʻohana, e hoʻopau i ka laina DOUT.
Aia hoʻokahi wahi, hoʻopuka ʻia nā lāʻau ma o UART (baud rate 115200, TX - 6 pins, RX - 8 pins) aia nā hoʻonohonoho āpau ma sdk_config.h
haʻina
Mahalo iā ʻoukou a pau no ko ʻoukou nānā ʻana, manaʻolana wau e pono kēia ʻatikala a e hōʻemi ana i ka manawa waiwai no nā mea hoʻomohala e ʻimi i kahi hopena. Makemake wau e ʻōlelo ʻo ke ala ʻenehana a Nordic e hoʻohana ai i kāna mau paepae he mea hoihoi loa ia mai ka manaʻo o ka pono o ka ikehu.
PS
Ke hoʻomohala nei ka papahana, no laila, inā makemake kēia kumuhana, ma ka ʻatikala aʻe e hoʻāʻo wau e wehewehe i ka algorithm no ka calibrating weight sensors, a me ka hoʻopili ʻana i ka waihona BLE.
Nā Pono
Source: www.habr.com