path: root/src/ds18b20/tm_stm32f4_onewire.c

/**	
 * |----------------------------------------------------------------------
 * | Copyright (C) Tilen Majerle, 2014
 * | 
 * | This program is free software: you can redistribute it and/or modify
 * | it under the terms of the GNU General Public License as published by
 * | the Free Software Foundation, either version 3 of the License, or
 * | any later version.
 * |  
 * | This program is distributed in the hope that it will be useful,
 * | but WITHOUT ANY WARRANTY; without even the implied warranty of
 * | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * | GNU General Public License for more details.
 * | 
 * | You should have received a copy of the GNU General Public License
 * | along with this program.  If not, see <http://www.gnu.org/licenses/>.
 * |----------------------------------------------------------------------
 */
#include "tm_stm32f4_onewire.h"

void usart_debug_puts(const char* str);
void delay(const uint64_t us);

static void
TM_GPIO_SetBits(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin)
{
    GPIO_SetBits(GPIOx, GPIO_Pin);
}

static void
TM_GPIO_ResetBits(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin)
{
    GPIO_ResetBits(GPIOx, GPIO_Pin);
}


static void
TM_GPIO_SetPinAsInput(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin)
{
    GPIO_SetBits(GPIOx, GPIO_Pin);
}

static void
TM_GPIO_SetPinAsOutput(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin)
{
#if 0
    GPIO_InitTypeDef GPIO_InitStructure;
    GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_OUT;
    GPIO_InitStructure.GPIO_Pin   = GPIO_Pin;
    GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_UP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_OType = GPIO_OType_OD;
    GPIO_Init(GPIOx, &GPIO_InitStructure);
#endif
    GPIO_ResetBits(GPIOx, GPIO_Pin);
}

static int
TM_GPIO_GetInputPinValue(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin)
{
    return GPIO_ReadInputDataBit(GPIOx, GPIO_Pin) ? 1 : 0;
}

static void
ONEWIRE_DELAY(int us)
{
    delay(us);
}

void TM_OneWire_Init(TM_OneWire_t* OneWireStruct, GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin) {
	ONEWIRE_INPUT(OneWireStruct);
	/* Save settings */
	OneWireStruct->GPIOx = GPIOx;
	OneWireStruct->GPIO_Pin = GPIO_Pin;
}

uint8_t TM_OneWire_Reset(TM_OneWire_t* OneWireStruct) {
	uint8_t i;
	
	/* Line low, and wait 480us */
	ONEWIRE_LOW(OneWireStruct);
	ONEWIRE_OUTPUT(OneWireStruct);
	ONEWIRE_DELAY(480);
	
	/* Release line and wait for 70us */
	ONEWIRE_INPUT(OneWireStruct);
	ONEWIRE_DELAY(70);
	
	/* Check bit value */
	i = TM_GPIO_GetInputPinValue(OneWireStruct->GPIOx, OneWireStruct->GPIO_Pin);
	
	/* Delay for 410 us */
	ONEWIRE_DELAY(410);
	
	/* Return value of presence pulse, 0 = OK, 1 = ERROR */
	return i;
}

void TM_OneWire_WriteBit(TM_OneWire_t* OneWireStruct, uint8_t bit) {
	if (bit) {
		/* Set line low */
		ONEWIRE_LOW(OneWireStruct);
		ONEWIRE_OUTPUT(OneWireStruct);
		ONEWIRE_DELAY(10);
		
		/* Bit high */
		ONEWIRE_INPUT(OneWireStruct);
		
		/* Wait for 55 us and release the line */
		ONEWIRE_DELAY(55);
		ONEWIRE_INPUT(OneWireStruct);
	} else {
		/* Set line low */
		ONEWIRE_LOW(OneWireStruct);
		ONEWIRE_OUTPUT(OneWireStruct);
		ONEWIRE_DELAY(65);
		
		/* Bit high */
		ONEWIRE_INPUT(OneWireStruct);
		
		/* Wait for 5 us and release the line */
		ONEWIRE_DELAY(5);
		ONEWIRE_INPUT(OneWireStruct);
	}

}

uint8_t TM_OneWire_ReadBit(TM_OneWire_t* OneWireStruct) {
	uint8_t bit = 0;
	
	/* Line low */
	ONEWIRE_LOW(OneWireStruct);
	ONEWIRE_OUTPUT(OneWireStruct);
	ONEWIRE_DELAY(3);
	
	/* Release line */
	ONEWIRE_INPUT(OneWireStruct);
	ONEWIRE_DELAY(10);
	
	/* Read line value */
	if (TM_GPIO_GetInputPinValue(OneWireStruct->GPIOx, OneWireStruct->GPIO_Pin)) {
		/* Bit is HIGH */
		bit = 1;
	}
	
	/* Wait 50us to complete 60us period */
	ONEWIRE_DELAY(50);
	
	/* Return bit value */
	return bit;
}

void TM_OneWire_WriteByte(TM_OneWire_t* OneWireStruct, uint8_t byte) {
	uint8_t i = 8;
	/* Write 8 bits */
	while (i--) {
		/* LSB bit is first */
		TM_OneWire_WriteBit(OneWireStruct, byte & 0x01);
		byte >>= 1;
	}
}

uint8_t TM_OneWire_ReadByte(TM_OneWire_t* OneWireStruct) {
	uint8_t i = 8, byte = 0;
	while (i--) {
		byte >>= 1;
		byte |= (TM_OneWire_ReadBit(OneWireStruct) << 7);
	}
	
	return byte;
}

uint8_t TM_OneWire_First(TM_OneWire_t* OneWireStruct) {
	/* Reset search values */
	TM_OneWire_ResetSearch(OneWireStruct);

	/* Start with searching */
	return TM_OneWire_Search(OneWireStruct, ONEWIRE_CMD_SEARCHROM);
}

uint8_t TM_OneWire_Next(TM_OneWire_t* OneWireStruct) {
   /* Leave the search state alone */
   return TM_OneWire_Search(OneWireStruct, ONEWIRE_CMD_SEARCHROM);
}

void TM_OneWire_ResetSearch(TM_OneWire_t* OneWireStruct) {
	/* Reset the search state */
	OneWireStruct->LastDiscrepancy = 0;
	OneWireStruct->LastDeviceFlag = 0;
	OneWireStruct->LastFamilyDiscrepancy = 0;
}

uint8_t TM_OneWire_Search(TM_OneWire_t* OneWireStruct, uint8_t command) {
	uint8_t id_bit_number;
	uint8_t last_zero, rom_byte_number, search_result;
	uint8_t id_bit, cmp_id_bit;
	uint8_t rom_byte_mask, search_direction;

	/* Initialize for search */
	id_bit_number = 1;
	last_zero = 0;
	rom_byte_number = 0;
	rom_byte_mask = 1;
	search_result = 0;

	// if the last call was not the last one
	if (!OneWireStruct->LastDeviceFlag) {
		// 1-Wire reset
		if (TM_OneWire_Reset(OneWireStruct)) {
			/* Reset the search */
			OneWireStruct->LastDiscrepancy = 0;
			OneWireStruct->LastDeviceFlag = 0;
			OneWireStruct->LastFamilyDiscrepancy = 0;
			return 0;
		}

		// issue the search command 
		TM_OneWire_WriteByte(OneWireStruct, command);  

		// loop to do the search
		do {
			// read a bit and its complement
			id_bit = TM_OneWire_ReadBit(OneWireStruct);
			cmp_id_bit = TM_OneWire_ReadBit(OneWireStruct);

			// check for no devices on 1-wire
			if ((id_bit == 1) && (cmp_id_bit == 1)) {
				break;
			} else {
				// all devices coupled have 0 or 1
				if (id_bit != cmp_id_bit) {
					search_direction = id_bit;  // bit write value for search
				} else {
					// if this discrepancy if before the Last Discrepancy
					// on a previous next then pick the same as last time
					if (id_bit_number < OneWireStruct->LastDiscrepancy) {
						search_direction = ((OneWireStruct->ROM_NO[rom_byte_number] & rom_byte_mask) > 0);
					} else {
						// if equal to last pick 1, if not then pick 0
						search_direction = (id_bit_number == OneWireStruct->LastDiscrepancy);
					}
					
					// if 0 was picked then record its position in LastZero
					if (search_direction == 0) {
						last_zero = id_bit_number;

						// check for Last discrepancy in family
						if (last_zero < 9) {
							OneWireStruct->LastFamilyDiscrepancy = last_zero;
						}
					}
				}

				// set or clear the bit in the ROM byte rom_byte_number
				// with mask rom_byte_mask
				if (search_direction == 1) {
					OneWireStruct->ROM_NO[rom_byte_number] |= rom_byte_mask;
				} else {
					OneWireStruct->ROM_NO[rom_byte_number] &= ~rom_byte_mask;
				}
				
				// serial number search direction write bit
				TM_OneWire_WriteBit(OneWireStruct, search_direction);

				// increment the byte counter id_bit_number
				// and shift the mask rom_byte_mask
				id_bit_number++;
				rom_byte_mask <<= 1;

				// if the mask is 0 then go to new SerialNum byte rom_byte_number and reset mask
				if (rom_byte_mask == 0) {
					//docrc8(ROM_NO[rom_byte_number]);  // accumulate the CRC
					rom_byte_number++;
					rom_byte_mask = 1;
				}
			}
		} while (rom_byte_number < 8);  // loop until through all ROM bytes 0-7

		// if the search was successful then
		if (!(id_bit_number < 65)) {
			// search successful so set LastDiscrepancy,LastDeviceFlag,search_result
			OneWireStruct->LastDiscrepancy = last_zero;

			// check for last device
			if (OneWireStruct->LastDiscrepancy == 0) {
				OneWireStruct->LastDeviceFlag = 1;
			}

			search_result = 1;
		}
	}

	// if no device found then reset counters so next 'search' will be like a first
	if (!search_result || !OneWireStruct->ROM_NO[0]) {
		OneWireStruct->LastDiscrepancy = 0;
		OneWireStruct->LastDeviceFlag = 0;
		OneWireStruct->LastFamilyDiscrepancy = 0;
		search_result = 0;
	}

	return search_result;
}

int TM_OneWire_Verify(TM_OneWire_t* OneWireStruct) {
	unsigned char rom_backup[8];
	int i,rslt,ld_backup,ldf_backup,lfd_backup;

	// keep a backup copy of the current state
	for (i = 0; i < 8; i++)
	rom_backup[i] = OneWireStruct->ROM_NO[i];
	ld_backup = OneWireStruct->LastDiscrepancy;
	ldf_backup = OneWireStruct->LastDeviceFlag;
	lfd_backup = OneWireStruct->LastFamilyDiscrepancy;

	// set search to find the same device
	OneWireStruct->LastDiscrepancy = 64;
	OneWireStruct->LastDeviceFlag = 0;

	if (TM_OneWire_Search(OneWireStruct, ONEWIRE_CMD_SEARCHROM)) {
		// check if same device found
		rslt = 1;
		for (i = 0; i < 8; i++) {
			if (rom_backup[i] != OneWireStruct->ROM_NO[i]) {
				rslt = 1;
				break;
			}
		}
	} else {
		rslt = 0;
	}

	// restore the search state 
	for (i = 0; i < 8; i++) {
		OneWireStruct->ROM_NO[i] = rom_backup[i];
	}
	OneWireStruct->LastDiscrepancy = ld_backup;
	OneWireStruct->LastDeviceFlag = ldf_backup;
	OneWireStruct->LastFamilyDiscrepancy = lfd_backup;

	// return the result of the verify
	return rslt;
}

void TM_OneWire_TargetSetup(TM_OneWire_t* OneWireStruct, uint8_t family_code) {
   uint8_t i;

	// set the search state to find SearchFamily type devices
	OneWireStruct->ROM_NO[0] = family_code;
	for (i = 1; i < 8; i++) {
		OneWireStruct->ROM_NO[i] = 0;
	}
	
	OneWireStruct->LastDiscrepancy = 64;
	OneWireStruct->LastFamilyDiscrepancy = 0;
	OneWireStruct->LastDeviceFlag = 0;
}

void TM_OneWire_FamilySkipSetup(TM_OneWire_t* OneWireStruct) {
	// set the Last discrepancy to last family discrepancy
	OneWireStruct->LastDiscrepancy = OneWireStruct->LastFamilyDiscrepancy;
	OneWireStruct->LastFamilyDiscrepancy = 0;

	// check for end of list
	if (OneWireStruct->LastDiscrepancy == 0) {
		OneWireStruct->LastDeviceFlag = 1;
	}
}

uint8_t TM_OneWire_GetROM(TM_OneWire_t* OneWireStruct, uint8_t index) {
	return OneWireStruct->ROM_NO[index];
}

void TM_OneWire_Select(TM_OneWire_t* OneWireStruct, uint8_t* addr) {
	uint8_t i;
	TM_OneWire_WriteByte(OneWireStruct, ONEWIRE_CMD_MATCHROM);
	
	for (i = 0; i < 8; i++) {
		TM_OneWire_WriteByte(OneWireStruct, *(addr + i));
	}
}

void TM_OneWire_SelectWithPointer(TM_OneWire_t* OneWireStruct, uint8_t *ROM) {
	uint8_t i;
	TM_OneWire_WriteByte(OneWireStruct, ONEWIRE_CMD_MATCHROM);
	
	for (i = 0; i < 8; i++) {
		TM_OneWire_WriteByte(OneWireStruct, *(ROM + i));
	}	
}

void TM_OneWire_GetFullROM(TM_OneWire_t* OneWireStruct, uint8_t *firstIndex) {
	uint8_t i;
	for (i = 0; i < 8; i++) {
		*(firstIndex + i) = OneWireStruct->ROM_NO[i];
	}
}

uint8_t TM_OneWire_CRC8(uint8_t *addr, uint8_t len) {
	uint8_t crc = 0, inbyte, i, mix;
	
	while (len--) {
		inbyte = *addr++;
		for (i = 8; i; i--) {
			mix = (crc ^ inbyte) & 0x01;
			crc >>= 1;
			if (mix) {
				crc ^= 0x8C;
			}
			inbyte >>= 1;
		}
	}
	
	/* Return calculated CRC */
	return crc;
}