From 08074f40515e60c8ae780059318d7a84129d70cf Mon Sep 17 00:00:00 2001 From: Miao Wang Date: Fri, 21 May 2021 16:48:57 +0800 Subject: [PATCH] one_wire: add search impl --- Core/Inc/one_wire.h | 16 +++- Core/Src/main.c | 8 +- Core/Src/one_wire.c | 212 +++++++++++++++++++++++++++++++++++++++++--- 3 files changed, 223 insertions(+), 13 deletions(-) diff --git a/Core/Inc/one_wire.h b/Core/Inc/one_wire.h index 3925f56..baacec6 100644 --- a/Core/Inc/one_wire.h +++ b/Core/Inc/one_wire.h @@ -14,14 +14,28 @@ typedef struct { uint8_t (*read_dq)(void *handle); } onewire_cb_t; +typedef struct { + uint8_t rom_num[8]; +} onewire_rom_num_t; + +typedef struct { + int LastDiscrepancy; + int LastFamilyDiscrepancy; + int LastDeviceFlag; + uint8_t crc8; + onewire_rom_num_t rom_num; +} onewire_search_t; + typedef struct { void *user_data; onewire_cb_t cb; + onewire_search_t _search_state; } onewire_t; uint8_t onewire_bus_reset(onewire_t *ow); onewire_ret_t onewire_bus_write_byte(onewire_t *ow, uint8_t byte); uint8_t onewire_bus_read_byte(onewire_t *ow); -onewire_ret_t onewire_bus_search_devices(onewire_t *ow); +onewire_ret_t onewire_bus_search_init(onewire_t *ow); +onewire_ret_t onewire_bus_search_nextdev(onewire_t *ow, onewire_rom_num_t *rom); #endif diff --git a/Core/Src/main.c b/Core/Src/main.c index c5f54ba..2e66436 100644 --- a/Core/Src/main.c +++ b/Core/Src/main.c @@ -108,7 +108,13 @@ int main(void) /* USER CODE BEGIN 2 */ onewire_bus_reset(&g_ow); - onewire_bus_search_devices(&g_ow); + + onewire_rom_num_t rom_num; + + onewire_bus_search_init(&g_ow); + while(onewire_bus_search_nextdev(&g_ow, &rom_num)){ + //register_ow_dev(rom_num); + } /* USER CODE END 2 */ diff --git a/Core/Src/one_wire.c b/Core/Src/one_wire.c index 4878529..360755b 100644 --- a/Core/Src/one_wire.c +++ b/Core/Src/one_wire.c @@ -87,15 +87,19 @@ uint8_t onewire_bus_reset(onewire_t *ow) { return device_response ? 0 : 1; } +static inline onewire_ret_t onewire_op_write_bit(onewire_t *ow, uint8_t bit) { + if(bit) { + onewire_op_write_one_bit(ow); + }else{ + onewire_op_write_zero_bit(ow); + } + + return OW_OK; +} + onewire_ret_t onewire_bus_write_byte(onewire_t *ow, uint8_t byte) { for(uint8_t i = 0; i < 8; i++) { - if(byte & 0x01) { - onewire_op_write_one_bit(ow); - } - else { - onewire_op_write_zero_bit(ow); - } - + onewire_op_write_bit(ow, byte & 0x01); byte >>= 1U; } @@ -115,11 +119,197 @@ uint8_t onewire_bus_read_byte(onewire_t *ow) { return result; } -onewire_ret_t onewire_bus_search_devices(onewire_t *ow) { - onewire_bus_write_byte(ow, 0xF0); // Search ROM command. +static uint8_t dscrc_table[] = { + 0, 94,188,226, 97, 63,221,131,194,156,126, 32,163,253, 31, 65, + 157,195, 33,127,252,162, 64, 30, 95, 1,227,189, 62, 96,130,220, + 35,125,159,193, 66, 28,254,160,225,191, 93, 3,128,222, 60, 98, + 190,224, 2, 92,223,129, 99, 61,124, 34,192,158, 29, 67,161,255, + 70, 24,250,164, 39,121,155,197,132,218, 56,102,229,187, 89, 7, + 219,133,103, 57,186,228, 6, 88, 25, 71,165,251,120, 38,196,154, + 101, 59,217,135, 4, 90,184,230,167,249, 27, 69,198,152,122, 36, + 248,166, 68, 26,153,199, 37,123, 58,100,134,216, 91, 5,231,185, + 140,210, 48,110,237,179, 81, 15, 78, 16,242,172, 47,113,147,205, + 17, 79,173,243,112, 46,204,146,211,141,111, 49,178,236, 14, 80, + 175,241, 19, 77,206,144,114, 44,109, 51,209,143, 12, 82,176,238, + 50,108,142,208, 83, 13,239,177,240,174, 76, 18,145,207, 45,115, + 202,148,118, 40,171,245, 23, 73, 8, 86,180,234,105, 55,213,139, + 87, 9,235,181, 54,104,138,212,149,203, 41,119,244,170, 72, 22, + 233,183, 85, 11,136,214, 52,106, 43,117,151,201, 74, 20,246,168, + 116, 42,200,150, 21, 75,169,247,182,232, 10, 84,215,137,107, 53}; - // Perform a binary search on the bus +const int FALSE = 0; +const int TRUE = 1; - return OW_OK; +//-------------------------------------------------------------------------- +// Calculate the CRC8 of the byte value provided with the current +// crc8_state. +// Returns current crc8_state value +// +uint8_t update_crc8(uint8_t *crc8_state, uint8_t value) +{ + // See Application Note 27 + + // TEST BUILD + *crc8_state = dscrc_table[*crc8_state ^ value]; + return *crc8_state; } +//-------------------------------------------------------------------------- +// Init device discovery on the 1-Wire bus +// Return OW_OK +// +onewire_ret_t onewire_bus_search_init(onewire_t *ow) +{ + // reset the search state + ow->_search_state.LastDiscrepancy = 0; + ow->_search_state.LastDeviceFlag = FALSE; + ow->_search_state.LastFamilyDiscrepancy = 0; + + return OW_OK; +} + +//-------------------------------------------------------------------------- +// Perform the 1-Wire Search Algorithm on the 1-Wire bus using the existing +// search state. +// Return OW_OK : device found, ROM number in ROM_NO buffer +// OW_ERROR : device not found, end of search +// +static inline onewire_ret_t onewire_bus_search(onewire_t *ow, onewire_rom_num_t *rom) +{ + int id_bit_number; + int last_zero, rom_byte_number, search_result; + int 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; + ow->_search_state.crc8 = 0; + + // if the last call was not the last one + if (!ow->_search_state.LastDeviceFlag) + { + // 1-Wire reset + if (!onewire_bus_reset(ow)) + { + // reset the search + ow->_search_state.LastDiscrepancy = 0; + ow->_search_state.LastDeviceFlag = FALSE; + ow->_search_state.LastFamilyDiscrepancy = 0; + return OW_ERROR; + } + + // issue the search command + onewire_bus_write_byte(ow, 0xF0); + + // loop to do the search + do + { + // read a bit and its complement + id_bit = onewire_op_read_bit(ow); + cmp_id_bit = onewire_op_read_bit(ow); + + // 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 < ow->_search_state.LastDiscrepancy) + search_direction = + ((ow->_search_state.rom_num.rom_num[rom_byte_number] + & rom_byte_mask) > 0); + else + // if equal to last pick 1, if not then pick 0 + search_direction = + (id_bit_number == ow->_search_state.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) + ow->_search_state.LastFamilyDiscrepancy = last_zero; + } + } + + // set or clear the bit in the ROM byte rom_byte_number + // with mask rom_byte_mask + if (search_direction == 1) + ow->_search_state.rom_num.rom_num[rom_byte_number] + |= rom_byte_mask; + else + ow->_search_state.rom_num.rom_num[rom_byte_number] + &= ~rom_byte_mask; + + // serial number search direction write bit + onewire_op_write_bit(ow, 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) + { + update_crc8(&ow->_search_state.crc8, + ow->_search_state.rom_num.rom_num[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) || (ow->_search_state.crc8 != 0))) + { + // search successful so set LastDiscrepancy,LastDeviceFlag,search_result + ow->_search_state.LastDiscrepancy = last_zero; + + // check for last device + if (ow->_search_state.LastDiscrepancy == 0) + ow->_search_state.LastDeviceFlag = TRUE; + + search_result = TRUE; + } + } + + // if no device found then reset counters so next 'search' will be like a first + if (!search_result || !ow->_search_state.rom_num.rom_num[0]) + { + ow->_search_state.LastDiscrepancy = 0; + ow->_search_state.LastDeviceFlag = FALSE; + ow->_search_state.LastFamilyDiscrepancy = 0; + search_result = FALSE; + } + if (search_result){ + *rom = ow->_search_state.rom_num; + return OW_OK; + }else{ + return OW_ERROR; + } +} + +//-------------------------------------------------------------------------- +// Find the 'next' devices on the 1-Wire bus +// Return OW_OK : device found, ROM number in rom buffer +// OW_ERROR : device not found, end of search +// +onewire_ret_t onewire_bus_search_nextdev(onewire_t *ow, onewire_rom_num_t *rom) +{ + // leave the search state alone + return onewire_bus_search(ow, rom); +}