Use the WREG command to write register data. Take CS1 low to access registers within the ADC register block. Take CS2 low to access registers within the PGA register block (see the Section 9.6 section for the register block map). The WREG command writes the register data one byte at a time using the WREG command for each operation. Add the register address (rrh) to the base value (40h) to complete the command byte (40h + rrh). Table 9-21 lists the WREG command byte sequence. Writing to certain registers results in conversion restart. Table 9-22 lists the affected registers. Do not write to registers outside the address range.