Z8 Expanded Register File - ZiLOG Z8 User Manual

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2.3 Z8 EXPANDED REGISTER FILE

The standard register file of the Z8 has been expanded to form
16 Expanded Register File (ERF) Banks (Figure 2-5). Each ERF
Bank consists of up to 256 registers (the same amount as in the
Working Register
Group Pointer
FF
F0
7F
0F
00
Note: The fully implemented register file is shown. Please refer to the specific product specification for actual register file architecture implemented.
Currently, three out of the possible sixteen Z8 ERF Banks have
been implemented. ERF Bank 0, also known as the Z8 Standard
UM001601-0803
Register Pointer
D7 D6 D5 D4 D3 D2 D1 D0
Expanded Register
Group Pointer
Z8 Register File
Figure 2-5. Expanded Register File Architecture
Standard Register File) that can then be divided into 16 Working
Register Groups. This expansion allows for access to additional
feature/peripheral control and data registers.
Expanded Register File
Bank (F)
(F) 0F WDTMR
(F) 0E (F) 0E Reserved Reserved
(F) 0D Reserved
(F) 0C Reserved
(F) 0B SMR
(F) 0A Reserved
(F) 09 Reserved
(F) 08 Reserved
(F) 07 Reserved
(F) 06 Reserved
(F) 05 Reserved
(F) 04 Reserved
(F) 03 Reserved
(F) 02 Reserved
(F) 01 Reserved
(F) 00 PCON
Expanded Register File
Bank (0)
(0) 0F GPR
(0) 0E GPR
(0) 0D GPR
(0) 0C GPR
(0) 0B GPR
(0) 0A GPR
(0) 09 GPR
(0) 08 GPR
(0) 07 GPR
(0) 06 GPR
(0) 05 GPR
(0) 04 GPR
(0) 03 P3
(0) 02 P2
(0) 01 P1
(0) 00 P0
Register File, has all 256 bytes defined (Figure 2-1). Only Work-
ing Register Group 0 (register addresses 00H to 0FH) have been
Z8 Microcontrollers
Address Space
Expanded Register File
Bank (C)
(C) 0F Reserved
(C) 0E Reserved
(C) 0D Reserved
(C) 0C Reserved
(C) 0B Reserved
(C) 0A Reserved
(C) 09 Reserved
(C) 08 Reserved
(C) 07 Reserved
(C) 06 Reserved
(C) 05 Reserved
(C) 04 Reserved
(C) 03 Reserved
(C) 02 SCON
(C) 01 RXBUF
(C) 00 SCOMP
2-5