I2C_CON
HWRITE4(sc, I2C_CON, sc->frequency);
HSET4(sc, I2C_CON, I2C_CON_ACK);
HCLR4(sc, I2C_CON, I2C_CON_ACK);
HCLR4(sc, I2C_CON, I2C_CON_INTPENDING);
if (!exiic_wait_state(sc, I2C_CON, I2C_CON_INTPENDING,