Tandy 1400LT Service Manual page 179

DMA, Timer
.
30
.
, BOO
BO1 29
1
BD2 28
.
1
BO3 27
1
BD4 26
~
1
BD5 23
~
I
BD6
22
I
BD7 21
A I 91
. A 2 92 I 7
A3 83 I 6
A4 94 I 5
A5 95 ,I4
~ A 6 96 I 3
A7 97 ,I2
9 +A8 B 8 { l 1
DATA BUS
DBO vcc
OBI
(*I
OB2
DB3
OB4
OB5
OB6
DB7
BA .BUS
BO. BUS
A . BUS
+5v
I
c2 1
0.01u +5v
+ + + I
DO +
D I
D2
D3
D4
D5
D6
D7
A15
A14
A13
A12
A l l
A10
A9
A8
BO4
BO3
BO2
BO 1
BOO
C23
+5v
0 . l u
t
(141 D D I R
-
BOO
BO
1
BD2
b03
b04
b05
b06
b07
BAO
BA 1
HR(
DACK 1
10 (I4) HDA
(1. 3, 14. 16. 17)
BEN
10 (2) I R Q O
05 OUT0
06
07
A0
(14) m . + d E
- 2 m
OUT2
(1. 3, 5, 8. 13. 14, 15. 16)
T/2 OUT
17 (15)
1 1
(1) DMACLK
(1. 3, 14, 16. 17) BEN
(2, 8, 14, 15)
m
(2, 8. 14, 15)
m
(8, 14)
BAA
( 8 )
m
(14)
OR0
(17) OR 1
(16) DR2
(17) DR3
(2. 5, 7, 12, 14. 16) BRST
13
1
530UT1
%
+5v
+07K
c22
0.01u
+ + 5 V
74HC244 P O
1 A l 1 Y 1
1A2 1 Y 2 . l 6
1 A 3 1 Y 3 . I 4
e
1A4 1Y4
l1 2A1 2Y1
i2
I 3 . 2 A 2 2Y2
2A3 2Y3
!7 ,2A4 2Y4,3
82C54 (uPD71054C)
U T c
(16. 17)
m
A0
A I
A2
A3
A4
A5
A6
A7
BAO
BA 1
BA2
BA3
BA4
BA5
BA6
BA7
1
l 6 DREQ3
13
25
rn
(14. 17)
*
(8, 14, 15)
IJAm
IC17 2 1
C19 23
R 8
RA8
(15) TIMERCLK
NO. 4
7-4