ZiLOG Z8 Technical Manual

Appendix B
Control Registers
Registers
R240 SIO
Serial 1/0 Register
(FO
H
;
Read/Write)
I~I~I~I~I~I~I~I~I
L-I __ SERIAL DATA (0, • LSB)
R241 TMR
Timer Mode Register
(FIH; Read/Write)
I~I~I~I~I~I~I~I~I
NOT USED ~ 00 -.J 1 = LOAD T,
~,g~~ : ~~ 0 = DISABLE T, COUNT
INTERNAL CLoCK OUT. 11 1 = ENABLE T, COUNT
TOUT MODES j ~~o = NO FUNCTION
T MODES 0 = NO FUNCTION
EXTERNAL CLOCK INP'OT • 00 1 = LOAD T,
2037-014
GATE INPUT = 01 0 = DISABLE T, COUNT
(NON.R~~~~g~~~~:~~ z 10 1 = ENABLE T, COUNT
TRIGGER INPUT = 11
(RETRIGGERABLE)
R242 TI
Counter Timer I Register
(F2H; Read/Write)
T, INITIAL VALUE (WHEN WRITTEN)
'-----(RANGE 1-256 DECIMAL 01-00 HEX)
T, CURRENT VALUE (WHEN READ)
R243 PREI
Prescaler I Register
(F3H; Write Only)
I~I~I~I~I~I~I~I~I
~L
COUNTMODE
o = T, SINGLE·PASS
1 = T, MODULO·N
CLOCK SOURCE
1
= T, INTERNAL
o = T, EXTERNAL TIMING INPUT
(T'N) MODE
PRESCALER MODULO
(RANGE: 1-64
DECIMAL
01-00
HEX)
R244 TO
Counter/Timer 0 Register
(F4H; Read/Write)
T,INITIAL VALUE (WHEN WRITTEN)
'-----(RANGE: 1-256 DECIMAL 01-00 HEX)
T, CURRENT VALUE (WHEN READ)
R245 PREO
Prescaler 0 Register
(F5
H
;
Write Only)
I~I~I~I~I~I~I~I~I
~L
COUNTMODE
o = To SINGLE·PASS
1 = T, MODULO·N
RESERVED
PRESCALER MODULO
(RANGE: 1-64 DECIMAL
01-00
HEX)
R246 P2M
Port
2 Mode Register
(F6H; Write Only)
P2,-P2, 1/0 DEFINITION
L- ___ 0 DEFINES BIT AS OUTPUT
1
DEFINES BIT AS INPUT
R247 P3M
Port 3 Mode Register
(F7
H
;
Write Only)
I~I~I~I~I~I~I~I~I
I PORT 2 PULL·UPS ACTIVE
RESERVED
o P32 = INPUT P35 = OUTPUT
[g~
LO PORT 2 PULL·UPS OPEN DRAIN
1 P32 = DAVOIRDYO P35 = RDYO/l!AVO
o 0 P33 = INPUT P34 = OUTPUT
~ ~ l P33 = INPUT P34 = DM
11 P33 = DAVlIRDYI P34 = RDYlIDAVI
o P31 = INPUT (T'N) P36 = OUTPUT (TOUT)
1 P31 = DAV2IRDY2 P36 = RDY2IOI\V2
L- ______ ~ ~~~ ~ ~Ne':t~!L IN ~~~ ~ ~~~rA~TOUT
L. ________ ~ ~:~:i~ g~F
B-1

ZiLOG Z8 Specifications

General

Brand	ZiLOG
Model	Z8
Category	Desktop
Language	English