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- /* Bit-banged open-drain I2C master: SCL=PD3, SDA=PD2 (external pull-ups required) */
- #ifndef I2C_H
- #define I2C_H
- #include <stdint.h>
- enum { I2C_OK = 0, I2C_NACK_ADDR = 1, I2C_NACK_DATA = 2, I2C_BUS_ERR = 3 };
- void i2c_init(void);
- void i2c_set_delay(uint8_t d); /* 0 = fastest, each step adds ~0.375 us per SCL period */
- uint8_t i2c_lines(uint8_t pullup); /* diag: bit0=SCL, bit1=SDA level; pullup=1 enables weak internal pull-ups */
- uint8_t i2c_recover(void); /* clock out stuck slave, then STOP */
- /* wlen>0: write phase; rlen>0: read phase (repeated START if both);
- * wlen==0 && rlen==0: address probe. addr is the 7-bit address. */
- uint8_t i2c_xfer(uint8_t addr, const uint8_t *w, uint8_t wlen, uint8_t *r, uint8_t rlen);
- #endif
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