FCR Function Control Register. 0x40000800 0x00 0x400 registers REG0 Register 0. 0x00 read-write USBRCKSEL USB External Core Clock Select. 16 1 sys Generated clock from system clock. 0 dig Digital clock from a GPIO. 1 I2C0DGEN0 I2C0 SDA Pad Deglitcher enable. 20 1 dis Deglitcher disabled. 0 en Deglitcher enabled. 1 I2C0DGEN1 I2C0 SCL Pad Deglitcher enable. 21 1 dis Deglitcher disabled. 0 en Deglitcher enabled. 1 I2C1DGEN0 I2C1 SDA Pad Deglitcher enable. 22 1 dis Deglitcher disabled. 0 en Deglitcher enabled. 1 I2C1DGEN1 I2C1 SCL Pad Deglitcher enable. 23 1 dis Deglitcher disabled. 0 en Deglitcher enabled. 1 REG1 Register 1. 0x04 read-write ACEN Auto-calibration Enable. 0 1 dis Disabled. 0 en Enabled. 1 ACRUN Autocalibration Run. 1 1 not Not Running. 0 run Running. 1 LDTRM Load Trim. 2 1 GAININV Invert Gain. 3 1 not Not Running. 0 run Running. 1 ATOMIC Atomic mode. 4 1 not Not Running. 0 run Running. 1 MU MU value. 8 12 REG2 Register 2. 0x08 read-write INITTRM Initial Trim Setting. 0 9 MINTRM Minimum Trim Setting. 10 9 MAXTRM Maximum Trim Setting. 20 9 REG3 Register 3. 0x0C read-write DONECNT Auto-callibration Done Counter Setting. 0 8