8.10.4 Accessing 24- and 32-bit Registers

For 24- and 32-bit registers, the read and write access is done in the same way as described for 16-bit registers, except there are two temporary registers for 24-bit registers and three temporary registers for 32-bit registers. The Most Significant Byte must be written last when writing to the register, and the Least Significant Byte must be read first when reading the register.