Yamaha DRX-1 Service Manual page 104

DRX-1
P89C51RD: IC7203
V
CC
V
SS
RAM ADDR
REGISTER
B
REGISTER
PSEN
ALE
TIMING
AND
EAV
PP CONTROL
RST
OSCILLATOR
XTAL1
104
7
17
Pin Function
1 NIC*
2 P1.0/T2
3 P1.1/T2EX
4 P1.2/ECI
5 P1.3/CEX0
6 P1.4/CEX1
7 P1.5/CEX2
8 P1.6/CEX3
9 P1.7/CEX4
10 RST
11 P3.0/RxD
12 NIC*
13 P3.1/TxD
14 P3.2/INT0
15 P3.3/INT1
P0.0±P0.7
PORT 0
DRIVERS
PORT 0
RAM
LATCH
ACC
TMP2
ALU
PSW
PORT 1
PD
LATCH
PORT 1
DRIVERS
XTAL2
P1.0±P1.7
6 1 40
39
LCC
29
18 28
Pin Function Pin Function
16 P3.4/T0 31 P2.7/A15
17 P3.5/T1 32 PSEN
33 ALE/PROG
18 P3.6/WR
34 NIC*
19 P3.7/RD
35 EA/V
20 XTAL2
PP
36 P0.7/AD7
21 XTAL1
37 P0.6/AD6
22 V
SS
38 P0.5/AD5
23 NIC*
39 P0.4/AD4
24 P2.0/A8
40 P0.3/AD3
25 P2.1/A9
41 P0.2/AD2
26 P2.2/A10
42 P0.1/AD1
27 P2.3/A11
43 P0.0/AD0
28 P2.4/A12
44 V
29 P2.5/A13
CC
30 P2.6/A14 * NO INTERNAL CONNECTION
P2.0±P2.7
PORT 2
DRIVERS
PORT 2
LATCH
STACK
POINTER
TMP1
SFRs
TIMERS
P.C.A.
PORT 3
LATCH
PORT 3
DRIVERS
P3.0±P3.7
FLASH
8
PROGRAM
ADDRESS
REGISTER
BUFFER
PC
INCRE-
MENTER
8 16
PROGRAM
COUNTER
DPTR'S
MULTIPLE