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I2C: improve bus signal probing

This commit is contained in:
King Kévin 2018-04-02 20:37:52 +02:00
parent 1065a37cdb
commit 5fa6a58e9b
1 changed files with 20 additions and 1 deletions
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21
lib/i2c_master.c
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@ -229,7 +229,26 @@ bool i2c_master_check_signals(uint32_t i2c)
while (true);
}
return (0!=gpio_get(GPIO_PORT_SCL(i2c), GPIO_PIN_SCL(i2c)) && 0!=gpio_get(GPIO_PORT_SDA(i2c), GPIO_PIN_SDA(i2c)));
// pull SDA and SDC low to check if there are pull-up resistors
uint32_t sda_crl = GPIO_CRL(GPIO_PORT_SDA(i2c)); // backup port configuration
uint32_t sda_crh = GPIO_CRH(GPIO_PORT_SDA(i2c)); // backup port configuration
uint32_t sda_bsrr = GPIO_BSRR(GPIO_PORT_SDA(i2c)); // backup port configuration
uint32_t scl_crl = GPIO_CRL(GPIO_PORT_SCL(i2c)); // backup port configuration
uint32_t scl_crh = GPIO_CRH(GPIO_PORT_SCL(i2c)); // backup port configuration
uint32_t scl_bsrr = GPIO_BSRR(GPIO_PORT_SCL(i2c)); // backup port configuration
gpio_set_mode(GPIO_PORT_SDA(i2c), GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, GPIO_PIN_SDA(i2c)); // configure signal as pull down
gpio_set_mode(GPIO_PORT_SCL(i2c), GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, GPIO_PIN_SCL(i2c)); // configure signal as pull down
gpio_clear(GPIO_PORT_SDA(i2c), GPIO_PIN_SDA(i2c)); // pull down
gpio_clear(GPIO_PORT_SCL(i2c), GPIO_PIN_SCL(i2c)); // pull down
bool to_return = (0!=gpio_get(GPIO_PORT_SCL(i2c), GPIO_PIN_SCL(i2c)) && 0!=gpio_get(GPIO_PORT_SDA(i2c), GPIO_PIN_SDA(i2c))); // check if the signals are still pulled high by external stronger pull-up resistors
GPIO_CRL(GPIO_PORT_SDA(i2c)) = sda_crl; // restore port configuration
GPIO_CRH(GPIO_PORT_SDA(i2c)) = sda_crh; // restore port configuration
GPIO_BSRR(GPIO_PORT_SDA(i2c)) = sda_bsrr; // restore port configuration
GPIO_CRL(GPIO_PORT_SCL(i2c)) = scl_crl; // restore port configuration
GPIO_CRH(GPIO_PORT_SCL(i2c)) = scl_crh; // restore port configuration
GPIO_BSRR(GPIO_PORT_SCL(i2c)) = scl_bsrr; // restore port configuration
return to_return;
}
void i2c_master_reset(uint32_t i2c)