Z86D99 ZILOG [Zilog, Inc.], Z86D99 Datasheet - Page 43

• Manufacturer Part Number: Z86D99
• Description: Low-Voltage Micro controllers with ADC
• Manufacturer: ZILOG [Zilog, Inc.]

PS003807-1002
The counter/timer, prescaler, and associated mode registers are mapped into the
register file as shown in Figure 19. The software uses the counter/timer as a gen-
eral-purpose register, which eliminates the need for special instructions.
Figure 19. Register File
Prescaler and Counter/Timer
The prescaler PRE
shown in Figure 18 on page 35. The prescaler register is a read-write register.
Figure 20 shows the prescaler register.
Figure 20. Prescaler 1 Register
DEC
243
242
241
D
7
D
6
Timer/counter 1
D
T1 prescaler
Timer mode
5
D
4
P
1
(
F3h
D
R
3
) consists of an 8-bit register and a 6-bit down-counter as
E
D
2
L
Prescaler 1 Register
Hex identifiers
F3 PRE1
F2 T1
F1 TMR
(
D
I
F3h
1
R243 PRE1
M
; Read/Write)
Z86D990/Z86D991 OTP and Z86L99X ROM
D
0
I
Low-Voltage Microcontrollers with ADC
N
A
Count mode
1 = T
0 = T
Clock source
1 = T
0 = T
Prescaler modulo
(range: 1–64 decimal,
01h – 00h )
R
1
1
1
1
Y
modulo-N
single pass
internal
external (T
IN
)
36