Modify peripheral UART example to use a GPIO pin as 1-wire interface to read DS18B20 temperature sensor.
This modified code works for RBL BLE Nano v2.0 (nRF52832, nRF5 SDK 14) but fails for RBL BLE Nano v1.0 (nRF51822, nRF5 SDK 11). 1-wire interface is working but
printf("%c%c\r\n", raw_temp >> 8, raw_temp & 0xff) doesn't.
The code for nRF51822 is attached for your reference. Please help to analyze why it fails. Thank you.
/** Copyright (c) 2014 Nordic Semiconductor. All Rights Reserved.
*
* The information contained herein is property of Nordic Semiconductor ASA.
* Terms and conditions of usage are described in detail in NORDIC
* SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
*
* Licensees are granted free, non-transferable use of the information. NO
* WARRANTY of ANY KIND is provided. This heading must NOT be removed from
* the file.
*
*/
/** @file
* @defgroup uart_example_main main.c
* @{
* @ingroup uart_example
* @brief UART Example Application main file.
*
* This file contains the source code for a sample application using UART.
*
*/
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include "app_uart.h"
#include "app_error.h"
#include "nrf_delay.h"
#include "nrf.h"
#include "bsp.h"
//DS18B20 stuff
#include "app_timer.h"
#include "nrf_drv_clock.h"
#include "nrf_drv_timer.h"
#include "string.h"
//#define ENABLE_LOOPBACK_TEST /**< if defined, then this example will be a loopback test, which means that TX should be connected to RX to get data loopback. */
#define MAX_TEST_DATA_BYTES (15U) /**< max number of test bytes to be used for tx and rx. */
//#define UART_TX_BUF_SIZE 256 /**< UART TX buffer size. */
//#define UART_RX_BUF_SIZE 1 /**< UART RX buffer size. */
#define UART_TX_BUF_SIZE 1024 /**< UART TX buffer size. */
#define UART_RX_BUF_SIZE 1024 /**< UART RX buffer size. */
//DS18B20 stuff
#define DS18B20PIN 4
void ds18b20_read(void * data_ptr, unsigned int num_bytes)
{
char ch; //Current reading byte buffer
char * data_buf = data_ptr;
int i=0,u=0;
for (i=0;i<num_bytes;i++)
{
ch=0;
for(u=0;u<8;u++)
{
//Form read slot
nrf_gpio_cfg_output(DS18B20PIN);
nrf_gpio_pin_write(DS18B20PIN,0);
nrf_delay_us(5);
nrf_gpio_cfg_input(DS18B20PIN, NRF_GPIO_PIN_NOPULL);
nrf_delay_us(5);
if(nrf_gpio_pin_read(DS18B20PIN)>0)
{
ch |= 1 << u; //There is 1 on the bus
}
else
{
ch &= ~(1 << u); //There us 0 on the bus
}
//Apply "long" timer for make sure that timeslot is end
nrf_delay_us(60);
}
data_buf[i]=ch;
}
nrf_gpio_cfg_input(DS18B20PIN, NRF_GPIO_PIN_NOPULL);
}
void ds18b20_write(void * data_ptr, unsigned int num_bytes)
{
char ch; //Current reading byte buffer
char * data_buf = data_ptr;
int i=0,u=0;
for (i=0;i<num_bytes;i++)
{
ch=data_buf[i];
for(u=0;u<8;u++)
{
//Form write slot
nrf_gpio_cfg_output(DS18B20PIN);
nrf_gpio_pin_write(DS18B20PIN,0);
nrf_delay_us(1);
//write 1 - pull bus to HIGH just after short timer
if(ch&(1<<u))
{
nrf_gpio_cfg_input(DS18B20PIN, NRF_GPIO_PIN_NOPULL);
}
//Apply "long" timer for make sure that timeslot is end
nrf_delay_us(60);
//Release bus, if this wasn't done before
nrf_gpio_cfg_input(DS18B20PIN, NRF_GPIO_PIN_NOPULL);
data_buf[i]=ch;
}
}
nrf_gpio_cfg_input(DS18B20PIN, NRF_GPIO_PIN_NOPULL);
}
//Perform reset of the bus, and then wait for the presence pulse
bool ds18b20_reset_and_check(void)
{
int res=0;
//Form reset pulse
nrf_gpio_cfg_output(DS18B20PIN);
nrf_gpio_pin_write(DS18B20PIN,0);
nrf_delay_us(500);
//Release bus and wait 15-60MS
nrf_gpio_cfg_input(DS18B20PIN, NRF_GPIO_PIN_NOPULL);
nrf_delay_us(60);
//Read from bus
res=nrf_gpio_pin_read(DS18B20PIN);
if(res==0)
{
nrf_delay_us(500);
return true;
}
return false;
}
/**
*@}
**/
int16_t ds18b20_read_temp(void)
{
char buf[16];
//double f;
//int i;
int16_t raw_temp=0;
ds18b20_reset_and_check();
//Read ROM
buf[0]=0x33;
ds18b20_write(&buf,1);
//Read the results
ds18b20_read(&buf,8);
memset(&buf,0,16);
//Send convert TX cmd
buf[0]=0x44; //Convert temp
ds18b20_write(&buf,1);
nrf_delay_ms(1000);//Wait for finishing of the conversion
ds18b20_reset_and_check();
buf[0]=0x33; //Read ROM
ds18b20_write(&buf,1);
//Read the results
ds18b20_read(&buf,8);
memset(&buf,0,16);
buf[0]=0xBE; //Read scratchpad
ds18b20_write(&buf,1);
//Read the results
ds18b20_read(&buf,9);
//raw_temp = (buf[1] << 4) | (buf[0] >> 4);
raw_temp = (buf[1] << 8) | buf[0];
//memcpy(&f,&buf,8);
//f=(float)raw_temp / 16.0;
return(raw_temp);
}
void uart_error_handle(app_uart_evt_t * p_event)
{
if (p_event->evt_type == APP_UART_COMMUNICATION_ERROR)
{
APP_ERROR_HANDLER(p_event->data.error_communication);
}
else if (p_event->evt_type == APP_UART_FIFO_ERROR)
{
APP_ERROR_HANDLER(p_event->data.error_code);
}
}
#ifdef ENABLE_LOOPBACK_TEST
/** @brief Function for setting the @ref ERROR_PIN high, and then enter an infinite loop.
*/
static void show_error(void)
{
LEDS_ON(LEDS_MASK);
while(true)
{
// Do nothing.
}
}
/** @brief Function for testing UART loop back.
* @details Transmitts one character at a time to check if the data received from the loopback is same as the transmitted data.
* @note @ref TX_PIN_NUMBER must be connected to @ref RX_PIN_NUMBER)
*/
static void uart_loopback_test()
{
uint8_t * tx_data = (uint8_t *)("\n\rLOOPBACK_TEST\n\r");
uint8_t rx_data;
// Start sending one byte and see if you get the same
for (uint32_t i = 0; i < MAX_TEST_DATA_BYTES; i++)
{
uint32_t err_code;
while(app_uart_put(tx_data[i]) != NRF_SUCCESS);
nrf_delay_ms(10);
err_code = app_uart_get(&rx_data);
if ((rx_data != tx_data[i]) || (err_code != NRF_SUCCESS))
{
show_error();
}
}
return;
}
#endif
/**
* @brief Function for main application entry.
*/
int main(void)
{
//LEDS_CONFIGURE(LEDS_MASK);
//LEDS_OFF(LEDS_MASK);
//DS18B20 stuff
uint32_t err_code;
err_code = nrf_drv_clock_init();
APP_ERROR_CHECK(err_code);
int16_t raw_temp;
const app_uart_comm_params_t comm_params =
{
RX_PIN_NUMBER,
TX_PIN_NUMBER,
RTS_PIN_NUMBER,
CTS_PIN_NUMBER,
APP_UART_FLOW_CONTROL_ENABLED,
false,
UART_BAUDRATE_BAUDRATE_Baud115200
};
APP_UART_FIFO_INIT(&comm_params,
UART_RX_BUF_SIZE,
UART_TX_BUF_SIZE,
uart_error_handle,
APP_IRQ_PRIORITY_LOW,
err_code);
APP_ERROR_CHECK(err_code);
/*
#ifndef ENABLE_LOOPBACK_TEST
printf("\n\rStart: \n\r");
while (true)
{
uint8_t cr;
while(app_uart_get(&cr) != NRF_SUCCESS);
while(app_uart_put(cr) != NRF_SUCCESS);
if (cr == 'q' || cr == 'Q')
{
printf(" \n\rExit!\n\r");
while (true)
{
// Do nothing.
}
}
}
#else
// This part of the example is just for testing the loopback .
while (true)
{
uart_loopback_test();
}
#endif
*/
printf("\n\rStart: \n\r");
while(true)
{
raw_temp = ds18b20_read_temp();
printf("%c%c\r\n", raw_temp >> 8, raw_temp & 0xff);
//nrf_delay_ms(100);
//app_uart_put(raw_temp >> 8);
//app_uart_put(raw_temp & 0xff);
//printf("read temp: %i.%i \r\n", raw_temp >> 4, (int)(((raw_temp & 0xf) >> 0)*6.25));
}
}
/** @} */
