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Code Issues Wiki Activity

Remove hardcoded numbers from i2cUnstick()

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This commit is contained in:
SteveCEvans 2018-05-01 00:18:45 +01:00
parent e282e4b3de
commit d009e40e38
2 changed files with 46 additions and 20 deletions
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33
src/main/drivers/bus_i2c_hal.c
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@ -37,6 +37,17 @@
#define CLOCKSPEED 800000 // i2c clockspeed 400kHz default (conform specs), 800kHz and 1200kHz (Betaflight default) #define CLOCKSPEED 800000 // i2c clockspeed 400kHz default (conform specs), 800kHz and 1200kHz (Betaflight default)
// Number of bits in I2C protocol phase
#define LEN_ADDR 7
#define LEN_RW 1
#define LEN_ACK 1
// Clock period in us during unstick transfer
#define UNSTICK_CLK_US 10
// Allow 500us for clock strech to complete during unstick
#define UNSTICK_CLK_STRETCH (500/UNSTICK_CLK_US)
static void i2cUnstick(IO_t scl, IO_t sda); static void i2cUnstick(IO_t scl, IO_t sda);
#define IOCFG_I2C_PU IO_CONFIG(GPIO_MODE_AF_OD, GPIO_SPEED_FREQ_VERY_HIGH, GPIO_PULLUP) #define IOCFG_I2C_PU IO_CONFIG(GPIO_MODE_AF_OD, GPIO_SPEED_FREQ_VERY_HIGH, GPIO_PULLUP)
@ -292,31 +303,33 @@ static void i2cUnstick(IO_t scl, IO_t sda)
IOConfigGPIO(scl, IOCFG_OUT_OD); IOConfigGPIO(scl, IOCFG_OUT_OD);
IOConfigGPIO(sda, IOCFG_OUT_OD); IOConfigGPIO(sda, IOCFG_OUT_OD);
// Analog Devices AN-686 // Clock out, with SDA high:
// We need 9 clock pulses + STOP condition // 7 data bits
for (i = 0; i < 9; i++) { // 1 READ bit
// 1 cycle for the ACK
for (i = 0; i < (LEN_ADDR + LEN_RW + LEN_ACK); i++) {
// Wait for any clock stretching to finish // Wait for any clock stretching to finish
int timeout = 100; int timeout = UNSTICK_CLK_STRETCH;
while (!IORead(scl) && timeout) { while (!IORead(scl) && timeout) {
delayMicroseconds(5); delayMicroseconds(UNSTICK_CLK_US);
timeout--; timeout--;
} }
// Pull low // Pull low
IOLo(scl); // Set bus low IOLo(scl); // Set bus low
delayMicroseconds(5); delayMicroseconds(UNSTICK_CLK_US/2);
IOHi(scl); // Set bus high IOHi(scl); // Set bus high
delayMicroseconds(5); delayMicroseconds(UNSTICK_CLK_US/2);
} }
// Generate a stop condition in case there was none // Generate a stop condition in case there was none
IOLo(scl); IOLo(scl);
delayMicroseconds(5); delayMicroseconds(UNSTICK_CLK_US/2);
IOLo(sda); IOLo(sda);
delayMicroseconds(5); delayMicroseconds(UNSTICK_CLK_US/2);
IOHi(scl); // Set bus scl high IOHi(scl); // Set bus scl high
delayMicroseconds(5); delayMicroseconds(UNSTICK_CLK_US/2);
IOHi(sda); // Set bus sda high IOHi(sda); // Set bus sda high
} }

33
src/main/drivers/bus_i2c_stm32f10x.c
View file

@ -37,6 +37,17 @@
#define CLOCKSPEED 800000 // i2c clockspeed 400kHz default (conform specs), 800kHz and 1200kHz (Betaflight default) #define CLOCKSPEED 800000 // i2c clockspeed 400kHz default (conform specs), 800kHz and 1200kHz (Betaflight default)
// Number of bits in I2C protocol phase
#define LEN_ADDR 7
#define LEN_RW 1
#define LEN_ACK 1
// Clock period in us during unstick transfer
#define UNSTICK_CLK_US 10
// Allow 500us for clock strech to complete during unstick
#define UNSTICK_CLK_STRETCH (500/UNSTICK_CLK_US)
static void i2c_er_handler(I2CDevice device); static void i2c_er_handler(I2CDevice device);
static void i2c_ev_handler(I2CDevice device); static void i2c_ev_handler(I2CDevice device);
static void i2cUnstick(IO_t scl, IO_t sda); static void i2cUnstick(IO_t scl, IO_t sda);
@ -480,31 +491,33 @@ static void i2cUnstick(IO_t scl, IO_t sda)
IOConfigGPIO(scl, IOCFG_OUT_OD); IOConfigGPIO(scl, IOCFG_OUT_OD);
IOConfigGPIO(sda, IOCFG_OUT_OD); IOConfigGPIO(sda, IOCFG_OUT_OD);
// Analog Devices AN-686 // Clock out, with SDA high:
// We need 9 clock pulses + STOP condition // 7 data bits
for (i = 0; i < 9; i++) { // 1 READ bit
// 1 cycle for the ACK
for (i = 0; i < (LEN_ADDR + LEN_RW + LEN_ACK); i++) {
// Wait for any clock stretching to finish // Wait for any clock stretching to finish
int timeout = 100; int timeout = UNSTICK_CLK_STRETCH;
while (!IORead(scl) && timeout) { while (!IORead(scl) && timeout) {
delayMicroseconds(5); delayMicroseconds(UNSTICK_CLK_US);
timeout--; timeout--;
} }
// Pull low // Pull low
IOLo(scl); // Set bus low IOLo(scl); // Set bus low
delayMicroseconds(5); delayMicroseconds(UNSTICK_CLK_US/2);
IOHi(scl); // Set bus high IOHi(scl); // Set bus high
delayMicroseconds(5); delayMicroseconds(UNSTICK_CLK_US/2);
} }
// Generate a stop condition in case there was none // Generate a stop condition in case there was none
IOLo(scl); IOLo(scl);
delayMicroseconds(5); delayMicroseconds(UNSTICK_CLK_US/2);
IOLo(sda); IOLo(sda);
delayMicroseconds(5); delayMicroseconds(UNSTICK_CLK_US/2);
IOHi(scl); // Set bus scl high IOHi(scl); // Set bus scl high
delayMicroseconds(5); delayMicroseconds(UNSTICK_CLK_US/2);
IOHi(sda); // Set bus sda high IOHi(sda); // Set bus sda high
} }