Library 12- OneWire library for STM32F4
1-Wire is a device communications bus system designed by Dallas Semiconductor Corp. that provides low-speed data, signaling, and power over a single signal.
It’s used in some temperature sensors, like DS18B20 temp sensor and many others products from Dallas.
OneWire key features
- Single Contact Sufficient for Control and Operation
- Unique ID Factory-Lasered in Each Device
- Power Derived from Signal Bus (“Parasitically Powered”)
- Multidrop Capable: Supports Multiple Devices on Single Line
- Exceptional ESD Performance
source: maximintegrated.com
17th May, 2014: There was some new functions added!
Library
Features
- Read/write byte
- Search for devices on 1-wire pin
- Read rom from device
- Version 2.0 – January 04, 2015
- Library rewritten
- It supports unlimited pins and gpios for OneWire
- This allows you to group sensors to separate ports to prevent communication failures if one sensor is broken
- Version 2.1 – March 10, 2015
- Supported new GPIO system
Dependencies
- CMSIS
- STM32F4xx
- STM32F4xx RCC
- STM32F4xx GPIO
- TM
- TM DELAY
- TO GPIO
- defines.h
- attributes.h
- TM DELAY
Initialize
Before you can work with 1-wire bus, you have to initialize it
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TM_OneWire_t OneWire; //Initialize One Wire on pin PD0 TM_OneWire_Init(&OneWire, GPIOD, GPIO_Pin_0); |
Reset pulse
If you need to reset 1-wire bus, simple call reset function
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//Reset 1-wire bus TM_OneWire_Reset(&OneWire); |
Write byte
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//Write byte to 1-wire slave TM_OneWire_WriteByte(&OneWire, uint8_t byte); |
Read byte
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//Read byte to 1-wire slave byte = TM_OneWire_ReadByte(&OneWire); |
Search devices
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uint8_t devices, count, device[5][8]; devices = TM_OneWire_First(&OneWire); count = 0; while (devices) { count++; //Get byte per byte for (i = 0; i < 8; i++) { device[count - 1][i] = TM_OneWire_GetROM(&OneWire, i); } //NEW: or pass pointer to first location for ROM and it will fill bytes for you //TM_OneWire_GetFullROM(&OneWire, &device[count - 1][0]) devices = TM_OneWire_Next(&OneWire); } |
Select device
Because you have more devices on one line, you have to somehow select device which you want to communicate with. You can do this with
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//Select 1-wire address //8 bytes ROM code is used as parameter TM_OneWire_Select(TM_OneWire_t* OneWireStruct, uint8_t addr[]); //NEW: You can select device with pointer to first byte of ROM like this TM_OneWire_SelectWithPointer(&OneWire, &ROM_addr[0]); |
Functions and enumerations
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/** * OneWire working struct * * Parameters: * - GPIO_TypeDef* GPIOx: * GPIOx port to be used for I/O functions * - uint16_t GPIO_Pin: * GPIO Pin to be used for I/O functions * - uint8_t LastDiscrepancy: * Search private * - uint8_t LastFamilyDiscrepancy: * Search private * - uint8_t LastDeviceFlag: * Search private * - uint8_t ROM_NO[8]: * 8-bytes address of last search device */ typedef struct { GPIO_TypeDef* GPIOx; uint16_t GPIO_Pin; uint8_t LastDiscrepancy; uint8_t LastFamilyDiscrepancy; uint8_t LastDeviceFlag; uint8_t ROM_NO[8]; } TM_OneWire_t; /** * Initialize OneWire bus * * Parameters: * - TM_OneWire_t* OneWireStruct: * Pointer to empty working onewire struct * - GPIO_TypeDef* GPIOx: * Pointer to GPIO used for onewire * - uint16_t GPIO_Pin: * GPIO Pin on specific GPIOx to be used for onewire * * No return */ extern void TM_OneWire_Init(TM_OneWire_t* OneWireStruct, GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin); /** * Reset OneWire bus * * Sends reset command for OneWire * * Parameters: * - TM_OneWire_t* OneWireStruct: * Pointer to TM_OneWire_t working struct * * No return */ extern uint8_t TM_OneWire_Reset(TM_OneWire_t* OneWireStruct); /** * Read byte from one wire bus * * Parameters: * - TM_OneWire_t* OneWireStruct: * Pointer to TM_OneWire_t working struct * * Byte is returned */ extern uint8_t TM_OneWire_ReadByte(TM_OneWire_t* OneWireStruct); /** * Write byte to bus * * Parameters: * - TM_OneWire_t* OneWireStruct: * Pointer to TM_OneWire_t working struct * - uint8_t byte: * Byte to be sent * * No return */ extern void TM_OneWire_WriteByte(TM_OneWire_t* OneWireStruct, uint8_t byte); /** * Write single bit to onewire bus * * Parameters: * - TM_OneWire_t* OneWireStruct: * Pointer to TM_OneWire_t working struct * - uint8_t bit: * bit to be sent, 1 or 0 * * No return */ extern void TM_OneWire_WriteBit(TM_OneWire_t* OneWireStruct, uint8_t bit); /** * Read single bit from one wire bus * * Parameters: * - TM_OneWire_t* OneWireStruct: * Pointer to TM_OneWire_t working struct * * Returns 0 if bit is low, or 1 if bit is high */ extern uint8_t TM_OneWire_ReadBit(TM_OneWire_t* OneWireStruct); /** * Search OneWire devices. * Not meant for public user use * * Parameters: * - TM_OneWire_t* OneWireStruct: * Pointer to TM_OneWire_t working struct * * Returns 1 if new device is recognized or 0 if not */ extern uint8_t TM_OneWire_Search(TM_OneWire_t* OneWireStruct, uint8_t command); /** * Reset search states * * Parameters: * - TM_OneWire_t* OneWireStruct: * Pointer to TM_OneWire_t working struct * * No return */ extern void TM_OneWire_ResetSearch(TM_OneWire_t* OneWireStruct); /** * Start search, reset states * * Parameters: * - TM_OneWire_t* OneWireStruct: * Pointer to TM_OneWire_t working struct * * Returns 1 if any device on bus */ extern uint8_t TM_OneWire_First(TM_OneWire_t* OneWireStruct); /** * Read next device * * Parameters: * - TM_OneWire_t* OneWireStruct: * Pointer to TM_OneWire_t working struct * * Returns 1 if more devices are on bus, otherwise 0 */ extern uint8_t TM_OneWire_Next(TM_OneWire_t* OneWireStruct); /** * Get rom from device from search * * Parameters * - TM_OneWire_t* OneWireStruct: * Pointer to TM_OneWire_t working struct * - uint8_t index: * because each device has 8bytes long rom, you have to call this 8 times, to get rom bytes from 0 to 7 * * Returns ROM byte for index (0 to 7) at current found device */ extern uint8_t TM_OneWire_GetROM(TM_OneWire_t* OneWireStruct, uint8_t index); /** * Get all 8 bytes ROM value from device from search * * Parameters * - TM_OneWire_t* OneWireStruct: * Pointer to TM_OneWire_t working struct * - uint8_t* firstIndex: * Pointer to first location for first byte, other bytes are automatically incremented * * No return */ extern void TM_OneWire_GetFullROM(TM_OneWire_t* OneWireStruct, uint8_t *firstIndex); /** * Select specific slave on bus * * Parameters: * - TM_OneWire_t* OneWireStruct: * Pointer to TM_OneWire_t working struct * - uint8_t* addr: * Pointer to 8 bytes ROM address * * No return */ extern void TM_OneWire_Select(TM_OneWire_t* OneWireStruct, uint8_t* addr); /** * Select specific slave on bus with pointer address * * Parameters: * - TM_OneWire_t* OneWireStruct: * Pointer to TM_OneWire_t working struct * - uint8_t* ROM: * pointer to first byte of ROM address * * No return */ extern void TM_OneWire_SelectWithPointer(TM_OneWire_t* OneWireStruct, uint8_t* ROM); /** * Calculate 8-bit CRC for 1-wire devices * * Parameters: * - uint8_t* addr: * Pointer to data to calculate CRC * - uint8_t len: * Number of bytes to check * * Calculated CRC is returned */ extern uint8_t TM_OneWire_CRC8(uint8_t* addr, uint8_t len); |
Example
I connected 2 DS18B20 sensors to PD0 (make sure, you have external pullup resistor) and this code returns me on terminal.
One Wire devices connected to STM32F4
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/** * Keil project for OneWire protocol library * * Before you start, select your target, on the right of the "Load" button * * @author Tilen Majerle * @email tilen@majerle.eu * @website http://stm32f4-discovery.net * @ide Keil uVision 5 * @packs STM32F4xx Keil packs version 2.2.0 or greater required * @stdperiph STM32F4xx Standard peripheral drivers version 1.4.0 or greater required */ /* Include core modules */ #include "stm32f4xx.h" /* Include my libraries here */ #include "defines.h" #include "tm_stm32f4_delay.h" #include "tm_stm32f4_onewire.h" #include "tm_stm32f4_usart.h" #include <stdio.h> int main(void) { char buf[30]; uint8_t devices, i, j, count, device[2][8]; /* OneWire working structure */ TM_OneWire_t OneWire1; /* Initialize system */ SystemInit(); /* Initialize delay */ TM_DELAY_Init(); /* Initialize OneWire1 instance on pin PD0 */ TM_OneWire_Init(&OneWire1, GPIOD, GPIO_Pin_0); /* Initialize USART, TX: PB6, RX: PB7 */ TM_USART_Init(USART1, TM_USART_PinsPack_2, 115200); /* Check for any device on 1-wire */ devices = TM_OneWire_First(&OneWire1); count = 0; while (devices) { /* Increase count variable */ count++; /* Get full 8-bytes rom address */ TM_OneWire_GetFullROM(&OneWire1, device[count - 1]); /* Check for new device */ devices = TM_OneWire_Next(&OneWire1); } /* If any devices on 1-wire */ if (count > 0) { sprintf(buf, "Devices found on 1-wire instance: %d\n", count); TM_USART_Puts(USART1, buf); /* Display 64bit rom code */ for (j = 0; j < count; j++) { for (i = 0; i < 8; i++) { sprintf(buf, "0x%02X ", device[j][i]); TM_USART_Puts(USART1, buf); } TM_USART_Puts(USART1, "\n"); } } else { /* Nothing on OneWire */ TM_USART_Puts(USART1, "No devices on OneWire.\n\n"); } while (1) { } } |
Example 2
- 4 devices are connected to STM32F4 via OneWire:
- 2 OneWire ports:
- PA3
- PD0
OneWire example with multi instances
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/** * Keil project for OneWire protocol library, 2 networks, PA3 and PD0 pins * * Before you start, select your target, on the right of the "Load" button * * Don't forget 4k7 pull up resistor! * * @author Tilen Majerle * @email tilen@majerle.eu * @website http://stm32f4-discovery.net * @ide Keil uVision 5 * @packs STM32F4xx Keil packs version 2.2.0 or greater required * @stdperiph STM32F4xx Standard peripheral drivers version 1.4.0 or greater required */ /* Include core modules */ #include "stm32f4xx.h" /* Include my libraries here */ #include "defines.h" #include "tm_stm32f4_delay.h" #include "tm_stm32f4_onewire.h" #include "tm_stm32f4_usart.h" #include <stdio.h> int main(void) { char buf[30]; uint8_t devices, i, j, count, device[2][8]; /* OneWire working structure */ TM_OneWire_t OneWire1, OneWire2; /* Initialize system */ SystemInit(); /* Initialize delay */ TM_DELAY_Init(); /* Initialize OneWire1 instance on pin PA3 */ TM_OneWire_Init(&OneWire1, GPIOA, GPIO_Pin_3); /* Initialize OneWire2 instance on pin PD0 */ TM_OneWire_Init(&OneWire2, GPIOD, GPIO_Pin_0); /* Initialize USART, TX: PB6, RX: PB7 */ TM_USART_Init(USART1, TM_USART_PinsPack_2, 115200); /* Check PA3 OneWire1 instance */ /* Check for any device on 1-wire port OneWire1 = PA3 */ devices = TM_OneWire_First(&OneWire1); count = 0; while (devices) { /* Increase count variable */ count++; /* Get full 8-bytes rom address */ TM_OneWire_GetFullROM(&OneWire1, device[count - 1]); /* Check for new device */ devices = TM_OneWire_Next(&OneWire1); } /* If any devices on 1-wire on pin PA3 */ if (count > 0) { sprintf(buf, "Devices found on 1-wire instance 1 (PA3): %d\n", count); TM_USART_Puts(USART1, buf); /* Display 64bit rom code */ for (j = 0; j < count; j++) { for (i = 0; i < 8; i++) { sprintf(buf, "0x%02X ", device[j][i]); TM_USART_Puts(USART1, buf); } TM_USART_Puts(USART1, "\n"); } } else { /* Nothing on OneWire */ TM_USART_Puts(USART1, "No devices on OneWire instance 1.\n\n"); } /* New line */ TM_USART_Puts(USART1, "\n"); /* Check PD3 OneWire2 instance */ /* Check for any device on 1-wire port OneWire2 = PD3 */ devices = TM_OneWire_First(&OneWire2); count = 0; while (devices) { /* Increase count variable */ count++; /* Get full 8-bytes rom address */ TM_OneWire_GetFullROM(&OneWire2, device[count - 1]); /* Check for new device */ devices = TM_OneWire_Next(&OneWire2); } /* If any devices on 1-wire on pin PD0 */ if (count > 0) { sprintf(buf, "Devices found on 1-wire instance 2 (PD0): %d\n", count); TM_USART_Puts(USART1, buf); /* Display 64bit rom code */ for (j = 0; j < count; j++) { for (i = 0; i < 8; i++) { sprintf(buf, "0x%02X ", device[j][i]); TM_USART_Puts(USART1, buf); } TM_USART_Puts(USART1, "\n"); } } else { /* Nothing on OneWire */ TM_USART_Puts(USART1, "No devices on OneWire instance 2.\n\n"); } /* New line */ TM_USART_Puts(USART1, "\n"); while (1) { } } |
Projects available on Github, download library below.
TM STM32F4 OneWire Library
OneWire library for onewire devices
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