I2C_SA
[I2C_SA] = 0x2c,
[I2C_SA] = 0xac,
I2C_WRITE_REG(sc, I2C_SA, (addr & I2C_SA_MASK));
DPRINTF(("SA 0x%x len %d\n", I2C_READ_REG(sc, I2C_SA), I2C_READ_REG(sc, I2C_CNT)));