Z86E3016PSG Datasheet, PDF (37/348 Pages) Zilog, Inc. – Z86E3016PSG

Z8 CPU
User Manual
19
Table 5. Register Pointer Access Example (Continued)
If R253 RP = FFh
;ERF Bank F, Working Reg. Group F.
00h = PCON
R0 = SI0
01h = Reserved
R1 = TMR 02h = Reserved
...
R2 = T1
0Bh = SMR
...
R15 = SPL 0Fh = WDTMR
Because enabling an ERF Bank (C or F) only changes register addresses
00h to 0Fh, the working register pointer can be used to access either the
selected ERF Bank (Bank C or F, Working Register Group 0) or the Z8^®
Standard Register File (ERF Bank 0, Working Register Groups 1 through
F).
When an ERF Bank other than Bank 0 is enabled, the first 16 bytes of the
Z8^® Standard Register File (I/O ports 0 to 3, Groups 4 to F) are no longer
accessible (the selected ERF Bank, Registers 00h to 0Fh are accessed
instead). It is important to re-initialize the Register Pointer to enable ERF
Bank 0 when these registers are required for use.
The SPI register is mapped into ERF Bank C. Access is easily done using
the example in Table 6.
UM001602-0904
Address Space