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gex-core/units/1wire/_ow_low_level.c

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4.3 KiB

//
// Created by MightyPork on 2018/01/29.
//
// 1-Wire unit low level functions
//
#include "platform.h"
#define OW_INTERNAL
#include "_ow_internal.h"
#include "_ow_low_level.h"
7 years ago
static inline uint8_t crc8_bits(uint8_t data)
{
uint8_t crc = 0;
if(data & 1) crc ^= 0x5e;
if(data & 2) crc ^= 0xbc;
if(data & 4) crc ^= 0x61;
if(data & 8) crc ^= 0xc2;
if(data & 0x10) crc ^= 0x9d;
if(data & 0x20) crc ^= 0x23;
if(data & 0x40) crc ^= 0x46;
if(data & 0x80) crc ^= 0x8c;
return crc;
}
static uint8_t crc8_add(uint8_t cksum, uint8_t byte)
{
return crc8_bits(byte ^ cksum);
}
uint8_t ow_checksum(const uint8_t *buff, uint32_t len)
{
uint8_t cksum = 0;
for(uint32_t i = 0; i < len; i++) {
cksum = crc8_add(cksum, buff[i]);
}
return cksum;
}
// ----------------------------------------------
static inline void ow_pull_high(Unit *unit)
{
struct priv *priv = unit->data;
LL_GPIO_SetOutputPin(priv->port, priv->ll_pin);
LL_GPIO_SetPinMode(priv->port, priv->ll_pin, LL_GPIO_MODE_OUTPUT);
}
static inline void ow_pull_low(Unit *unit)
{
struct priv *priv = unit->data;
LL_GPIO_ResetOutputPin(priv->port, priv->ll_pin);
LL_GPIO_SetPinMode(priv->port, priv->ll_pin, LL_GPIO_MODE_OUTPUT);
}
static inline void ow_release_line(Unit *unit)
{
struct priv *priv = unit->data;
LL_GPIO_SetPinMode(priv->port, priv->ll_pin, LL_GPIO_MODE_INPUT);
}
static inline bool ow_sample_line(Unit *unit)
{
struct priv *priv = unit->data;
return (bool) LL_GPIO_IsInputPinSet(priv->port, priv->ll_pin);
}
/**
* Reset the 1-wire bus
*/
bool ow_reset(Unit *unit)
{
ow_pull_low(unit);
PTIM_MicroDelay(500);
bool presence;
vPortEnterCritical();
{
// Strong pull-up (for parasitive power)
ow_pull_high(unit);
PTIM_MicroDelay(2);
// switch to open-drain
ow_release_line(unit);
PTIM_MicroDelay(118);
presence = !ow_sample_line(unit);
}
vPortExitCritical();
PTIM_MicroDelay(130);
return presence;
}
/**
* Write a bit to the 1-wire bus
*/
void ow_write_bit(Unit *unit, bool bit)
{
vPortEnterCritical();
{
// start mark
ow_pull_low(unit);
PTIM_MicroDelay(2);
if (bit) ow_pull_high(unit);
PTIM_MicroDelay(70);
// Strong pull-up (for parasitive power)
ow_pull_high(unit);
}
vPortExitCritical();
PTIM_MicroDelay(2);
}
/**
* Read a bit from the 1-wire bus
*/
bool ow_read_bit(Unit *unit)
{
bool bit;
vPortEnterCritical();
{
// start mark
ow_pull_low(unit);
PTIM_MicroDelay(2);
ow_release_line(unit);
PTIM_MicroDelay(20);
bit = ow_sample_line(unit);
}
vPortExitCritical();
PTIM_MicroDelay(40);
return bit;
}
/**
* Write a byte to the 1-wire bus
*/
void ow_write_u8(Unit *unit, uint8_t byte)
{
for (int i = 0; i < 8; i++) {
ow_write_bit(unit, 0 != (byte & (1 << i)));
}
}
/**
* Write a halfword to the 1-wire bus
*/
void ow_write_u16(Unit *unit, uint16_t halfword)
{
ow_write_u8(unit, (uint8_t) (halfword & 0xFF));
ow_write_u8(unit, (uint8_t) ((halfword >> 8) & 0xFF));
}
/**
* Write a word to the 1-wire bus
*/
void ow_write_u32(Unit *unit, uint32_t word)
{
ow_write_u16(unit, (uint16_t) (word));
ow_write_u16(unit, (uint16_t) (word >> 16));
}
/**
* Write a doubleword to the 1-wire bus
*/
void ow_write_u64(Unit *unit, uint64_t dword)
{
ow_write_u32(unit, (uint32_t) (dword));
ow_write_u32(unit, (uint32_t) (dword >> 32));
}
/**
* Read a byte form the 1-wire bus
*/
uint8_t ow_read_u8(Unit *unit)
{
uint8_t buf = 0;
for (int i = 0; i < 8; i++) {
buf |= (1 & ow_read_bit(unit)) << i;
}
return buf;
}
/**
* Read a halfword form the 1-wire bus
*/
uint16_t ow_read_u16(Unit *unit)
{
uint16_t acu = 0;
acu |= ow_read_u8(unit);
acu |= ow_read_u8(unit) << 8;
return acu;
}
/**
* Read a word form the 1-wire bus
*/
uint32_t ow_read_u32(Unit *unit)
{
uint32_t acu = 0;
acu |= ow_read_u16(unit);
acu |= (uint32_t)ow_read_u16(unit) << 16;
return acu;
}
/**
* Read a doubleword form the 1-wire bus
*/
uint64_t ow_read_u64(Unit *unit)
{
uint64_t acu = 0;
acu |= ow_read_u32(unit);
acu |= (uint64_t)ow_read_u32(unit) << 32;
return acu;
}