z86l88 ZiLOG Semiconductor, z86l88 Datasheet - Page 39

• Manufacturer Part Number: z86l88
• Description: Low-voltage Ir Microcontroller
• Manufacturer: ZiLOG Semiconductor

PS024102-0804
Register File
Note:
Figure 27. Register Pointer—FDH: Read/Write
Figure 28. Stack Pointer High—FEH: Read/Write
Figure 29. Stack Pointer Low—FFH: Read/Write
The register file (bank 0) consists of 4 I/O port registers, 237 general-purpose reg-
isters, and 16 control and status registers (R0–R3, R4–R239, and R240–255,
respectively). Additionally, there are two expanded registers groups in Banks D
and F. Instructions can access registers directly or indirectly through an 8-bit
address field, thereby allowing a short, 4-bit register address to use the Register
Pointer (Figure 30). In the 4-bit mode, the register file is divided into 16 working
register groups, each occupying 16 continuous locations. The Register Pointer
addresses the starting location of the active working register group.
Default setting after
reset = 0000 0000
R253 RP
R254 SPH
R255 SPL
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
Working register group E0–EF can only be accessed through
working registers and indirect addressing modes.
General-Purpose Register
Byte (SP15–SP8)
Expanded Register Bank
Pointer
Working Register
Pointer
Stack Pointer Lower
Byte (SP7–SP0)
Low-Voltage IR Microcontroller
Z86L88
32