Z86319 Datasheet, PDF (14/23 Pages) Zilog, Inc. – PS/2 MOUSE CONTROLLER

Z86319
PS/2 Mouse Controller
Zilog
FUNCTIONAL DESCRIPTION (Continued)
Program Memory. The Z86319 can address up to 2 KB
of internal program memory (Figure 14). The first 12 bytes
of program memory are reserved for the interrupt vectors.
These locations contain four 16-bit vectors that corre-
spond to the four available interrupts. Bytes 0-2047 are
on-chip mask-programmed ROM.
2047
Location of
First Byte of
Instruction
Executed
After RESET 12
11
10
9
8
7
Interrupt
Vector ₆
(Lower Byte)
5
4
Interrupt
Vector ₃
(Upper Byte)
2
1
0
On-Chip
ROM
IRQ5
IRQ5
IRQ4
IRQ4
Reserved
Reserved
IRQ2
IRQ2
IRQ1
IRQ1
Reserved
Reserved
Register File. The Register File consists of three I/O
port registers, 125 general-purpose registers, and 14 con-
trol and status registers, R0-R3, R4-R127 and R241-
R255, respectively (Figure 15). The Z86319 instructions
can access registers directly or indirectly via an 8-bit ad-
dress field. This field allows short, 4-bit register addressing
using the Register Pointer. In the 4-bit mode, the register
file is divided into eight working register groups, each oc-
cupying 16 continuous locations. The Register Pointer ad-
dresses the starting location of the active working-register
group.
LOCATION
R255
R254
R253
R252
R251
R250
R249
R248
R247
R246
R245
R244
R243
R242
R241
R240
Stack Pointer (Bits 7-0)
General-Purpose
Register Pointer
Program Control Flags
Interrupt Mask Register
Interrupt Request Register
Interrupt Priority Register
Ports 0-1 Mode
Port 3 Mode
Port 2 Mode
T0 Prescaler
Timer/Counter0
T1 Prescaler
Timer/Counter1
Timer Mode
IDENTIFIERS
SPL
GPR
RP
FLAGS
IMR
IRQ
IPR
P01M
P3M
P2M
PRE0
T0
PRE1
T1
TMR
Figure 14. Program Memory Map
R128
R127
R4
R3
R2
R1
R0
Not Implemented
General-Purpose
Registers
Port 3
P3
Port 2
P2
Reserved
Port 0
P0
Figure 15. Register File
14
PRELIMINARY
DS97KEY1605