Z86E6116PSC Datasheet, PDF (23/69 Pages) Zilog, Inc. – Z86E61/Z86E63 CMOS Z8 16K/32K EPROM Microcontroller

Z86E61/E63
CMOS Z8 16K/32K EPROM Microcontroller
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space (Figure 12). The state of the DM signal is controlled by the type instruction
being executed. An LDC opcode references PROGRAM (DM inactive) memory,
and an LDE instruction references DATA (DM active Low) memory.
Register File
The register file consists of four I/0 port registers, 236 general-purpose registers,
and 16 control and status registers (Figure 13). The instructions can access regis-
ters directly or indirectly through an 8-bit address field. The Z86E61/E63 also
allows short 4-bit register addressing using the Register Pointer (Figure 14). In the
4-bit mode, the Register File is divided into 16 working register groups, each occu-
pying 16 continuous locations. The Register Pointer addresses the starting loca-
tion of the active working register group.
Stack
The Z86E61/E63 has a 16-bit Stack Pointer (R255-R254) used for external stacks
that reside anywhere in the data memory for the ROMless mode, but only from
16384 (E61) or 32768 (E63) to 65535 in the EPROM mode. An 8-bit Stack Pointer
(R255) is used for the internal stack that resides within the 236 general-purpose
registers (R239-R4). The high byte of the Stack Pointer (SPH Bits 15-8) can be
use as a general purpose register when using internal stack only.
PS014401-1001