Tandy 26-3334 Service Manual page 95

NTSC
IC4: MC68B21P
IC5:
LSC81001P
IRQA 38
DO
33-
—
VCC
gO
VSS
cso
est
CS2
BSO
RSI
B/W
ENABLE
RESET
IRQB
22
Hz-
DATA
BUS
BUFFERS
(DBBI
rro
C
_c
CONTROL
REGISTER A
(CRA)
±1
BUS INPUT
REGISTER
IBIR)
OUTPUT BUS
b
CHIP
SELECT
and
R/W
CONTROL
OUTPUT
REGISTER
A
(ORA)
b
OUTPUT
REGISTER
B
(ORB)
CONTROL
REGISTER
B
(CRB)
INTERRUPT
STATUS
CONTROL
A
4CJCA1
|CA2
2
DATA
DIRECTtON
REGISTER A
(DDRA)
5
H
PERIPHERAL
INTERFACE
A
PERIPHERAL
INTERFACE
B
^
77
DATA DIRECTION
REGISTER
B
(DDRB)
INTERRUPT
STATUS
CONTROL
B
PAO
PA1
PA2
PA3
PA4
PA5
PA6
PA7
PBO
PB1
PB2
PB3
PB4
P85
PB6
PB7
is]
CB1
IS]
CB2
-95-