UPD784907 Datasheet, PDF (26/98 Pages) NEC – 16-BIT SINGLE-CHIP MICROCONTROLLER

µPD784907, 784908
7.2.2 Control registers
(1) Program counter (PC)
This register is a 20-bit program counter. The program counter is automatically updated by program execution.
Figure 7-4. Format of Program Counter (PC)
19
0
PC
(2) Program Status Word (PSW)
This register holds the CPU state. The program status word is automatically updated by program execution.
Figure 7-5. Format of Program Status Word (PSW)
15
14
13
12
11
10
9
8
PSWH UF RBS2 RBS1 RBS0
PSW
7
PSWL
S
6
5
4
3
2
1
0
Z
RSS^Note AC
IE
P/V
0
CY
Note This flag is used to maintain compatibility with the 78K/III Series. This flag must be set to 0 when
programs for the 78K/III Series are not being used.
(3) Stack pointer (SP)
This register is a 24-bit pointer for holding the start address of the stack.
The higher 4 bits must be set to 0.
Figure 7-6. Format of Stack Pointer (SP)
23
20
0
SP
00 00
26
Data Sheet U11680EJ2V0DS00