Z8
®
CPU
User Manual
UM001604-0108
Reset
34
Program execution starts 5 to 10 clock cycles after internal RESET has returned High. The
initial instruction fetch is from location
000Ch
.
on page 35 displays reset tim-
ing.
Table 12. Sample Control and Peripheral Register Reset Values (ERF Bank 0)
Register
(Hex)
Register Name
Bits
Comments
7
6
5
4
3
2
1
0
F0
Serial I/O
U U U U U U U U
F1
Timer Mode
0
0
0
0
0
0
0
0 Counter/Timers stopped.
F2
Counter/Timer1
U U U U U U U U
F3
T1 Prescaler
U U U U U U
0
0 Single-pass count mode,
external clock source.
F4
Counter/Timer0
U U U U U U U U
F5
T0 Prescaler
U U U U U U U
0 Single-pass count mode.
F6
Port 2 Mode
1
1
1
1
1
1
1
1 All inputs.
F7
Port 3 Mode
0
0
0
0
0
0
0
0 Port 2 open-drain, P33–P30
Input, P37–P34 Output.
F8
Port 0–1 Mode
0
1
0
0
1
1
0
1 Internal Stack, Normal Memory
Timing.
F9
Interrupt Priority
U U U U U U U U
FA
Interrupt Request
0
0
0
0
0
0
0
0 All Interrupts Cleared.
FB
Interrupt Mask
0
U U U U U U U Interrupts Disabled.
FC
Flags
U U U U U U U U
FD
Register Pointer
0
0
0
0
0
0
0
0
FE
Stack Pointer (High)
U U U U U U U U
FF
Stack Pointer (Low)
U U U U U U U U