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