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one_wire: add search impl

This commit is contained in:
Miao Wang 2021-05-21 16:48:57 +08:00
parent e3b8c5fc5f
commit 08074f4051
3 changed files with 223 additions and 13 deletions
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16
Core/Inc/one_wire.h
View File

@ -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

8
Core/Src/main.c
View File

@ -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 */

212
Core/Src/one_wire.c
View File

@ -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);
}