159 lines
3.6 KiB
C
159 lines
3.6 KiB
C
// LED blink and serial interface on nRF52832 breakout board
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// See iosoft.blog for details
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#include <stdarg.h>
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#include "nrf_gpio.h"
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#include "nrf_drv_systick.h"
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#include "nrfx_uart.h"
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#include "nrf_fprintf.h"
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// LED definitions
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#define REG_EN_PIN 15
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#define REG_EN_BIT (1 << REG_EN_PIN)
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#define PWR_EN_PIN 12
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#define PWR_EN_BIT (1 << PWR_EN_PIN)
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// UART definitions
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#define UART_PIN_DISCONNECTED 0xFFFFFFFF
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#define UART_TX_PIN 18
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#define UART_RX_PIN 20
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#define UART_RTS_PIN UART_PIN_DISCONNECTED
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#define UART_CTS_PIN UART_PIN_DISCONNECTED
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#define UART_BAUD NRF_UART_BAUDRATE_115200
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#define UART_BUFF_SIZE 1024
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#define PRINTF_BUFF_SIZE 1024
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#define SER_TX_BUFFLEN 1500
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uint32_t msticks, systicks;
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char printf_buff[PRINTF_BUFF_SIZE];
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// Circular buffer for serial Tx
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int ser_txin=0, ser_txout=0;
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uint8_t ser_txbuff[SER_TX_BUFFLEN];
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void init_gpio(void);
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int mstimeout(uint32_t *tickp, uint32_t msec);
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void init_serial(void);
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void poll_serial(void);
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int putch(int c);
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void uart_event_handler(nrfx_uart_event_t const * evtp, void *ctxp);
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void uart_tx(void const *ctxt, char const *buff, size_t len);
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// Context for printf function
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nrf_fprintf_ctx_t fprintf_ctx =
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{
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.p_io_buffer=printf_buff, .io_buffer_size=PRINTF_BUFF_SIZE,
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.fwrite = uart_tx
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};
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// Context for UART 0
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nrfx_uart_t nrfx_uart =
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{
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NRF_UART0, 0
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};
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int main(void) {
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uint32_t tix;
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mstimeout(&tix, 0);
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init_gpio();
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init_serial();
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printf("\nNRF52 test\n");
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NRF_GPIO->OUT |= PWR_EN_BIT;
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while (1) {
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if (mstimeout(&tix, 500)) {
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NRF_GPIO->OUT ^= REG_EN_BIT;
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putch('.');
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}
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poll_serial();
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}
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}
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// Initialise I/O port, and system tick counter
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void init_gpio(void) {
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nrf_gpio_cfg_output(REG_EN_PIN);
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nrf_gpio_cfg_output(PWR_EN_PIN);
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nrf_drv_systick_init();
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}
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// Check for timeout in milliseconds
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int mstimeout(uint32_t *tickp, uint32_t msec) {
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uint32_t t, diff;
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t = nrf_systick_val_get();
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diff = NRF_SYSTICK_VAL_MASK & (systicks - t);
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if (msec == 0) {
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systicks = t;
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*tickp = msticks;
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} else if ((diff /= SystemCoreClock/1000) > 0) {
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systicks = t;
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msticks += diff;
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diff = msticks - *tickp;
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if (diff >= msec) {
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*tickp = msticks;
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return(1);
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}
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}
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return(0);
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}
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// Formatted print to serial port
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int printf(const char *fmt, ...) {
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va_list args;
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int n;
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va_start(args, fmt);
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nrf_fprintf(&fprintf_ctx, fmt, &args);
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n = fprintf_ctx.io_buffer_cnt;
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nrf_fprintf_buffer_flush(&fprintf_ctx);
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va_end(args);
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return(n);
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}
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// Initialise serial I/O
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void init_serial(void) {
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const nrfx_uart_config_t config = {
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UART_TX_PIN, UART_RX_PIN,
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UART_CTS_PIN, UART_RTS_PIN, 0,
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NRF_UART_HWFC_DISABLED, 0, UART_BAUD,
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APP_IRQ_PRIORITY_LOWEST};
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nrfx_uart_init(&nrfx_uart, &config, 0);
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}
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// Poll serial interface, send next Tx char
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void poll_serial(void) {
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uint8_t b;
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if (ser_txin!=ser_txout && !nrfx_uart_tx_in_progress(&nrfx_uart)) {
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b = ser_txbuff[ser_txout++];
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if (ser_txout >= SER_TX_BUFFLEN)
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ser_txout = 0;
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nrfx_uart_tx(&nrfx_uart, &b, 1);
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}
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}
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// Add character to serial Tx circular buffer
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// Discard character if buffer is full
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int putch(int c) {
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int in=ser_txin+1;
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if (in >= SER_TX_BUFFLEN)
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in = 0;
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if (in != ser_txout) {
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ser_txbuff[ser_txin] = (uint8_t)c;
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ser_txin = in;
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}
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return(c);
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}
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// Send data block to UART (via circular buffer)
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void uart_tx(void const *ctxp, char const *buff, size_t len) {
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while (len--)
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putch(*buff++);
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}
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// Dummy UART event handler
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void uart_event_handler(nrfx_uart_event_t const * evtp, void *ctxp) {
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}
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