NPCM_I2CCTL1_START
(NPCM_I2CCTL1_START | NPCM_I2CCTL1_STOP | NPCM_I2CCTL1_ACK)
val |= NPCM_I2CCTL1_START;
val &= ~(NPCM_I2CCTL1_START | NPCM_I2CCTL1_ACK);
val &= ~(NPCM_I2CCTL1_STOP | NPCM_I2CCTL1_START);