Motorola M6800 - Manual (Page 2)

MPU-2
Microprocessing Unit (MC6800)
The nucleus of the M6800 Microcomputer Family is the microprocessing
unit (MPU). The MPU is enclosed in a 40 pin package as shown below:
Features included in the MPU are:
1. Two accumulators (ACCA and ACCB)
2. One index register (X)
3. One program counter register (PC)
4. One stack pointer register (SP)