Service manual

Pin
NO.
Name ER-A770 I/O Description
54 D2 D2 IO Data bus (CPU)
55 D3 D3 IO Data bus (CPU)
56 GND GND GND
57 D4 D4 IO Data bus (CPU)
58 D5 D5 IO Data bus (CPU)
59 D6 D6 IO Data bus (CPU)
60 D7 D7 IO Data bus (CPU)
61 GND GND GND
62 VCC VCC +5V
63 X1 NC O OSI14 NC
64 X2 # I OSI14 System clock
65 XOUT CLK_USART O Clock (USART)
66 TRCK NC O NC
67 AB0 AH0 O
Address bus for
USART
68 AB1 AH1 O
Address bus for
USART
69 US1CH GND IS GND
70 PX NC O NC
71 /POF /POFF IS POFF signal
72 /RSRQ /IRQ1 3S RS232 INTRRUPT
73 /TRV GND IS GND
74 RXDATA0 NC O NC
75 TXE /SRESET O
INLINE SOFT
RESET
76 /TRRQ /TRQ2 3S INLINE INTRRUPT
77 /TRQ1 /TRQ1 ON6
TIMER INTRRUPT
(RS232)
78 /TRQ2 NC ON6
TIMER INTRRUPT
(INLINE)
79 A0 A0 I Address bus for CPU
80 A1 A1 I Address bus for CPU
81 A2 A2 I Address bus for CPU
82 A3 A3 I Address bus for CPU
83 A4 A4 I Address bus for CPU
84 A5 A5 I Address bus for CPU
85 /OPTCS /OPTCS I
Option chip select
(from MPCA)
86 /RD /RDO I
Read signal
(from CPU)
87 /WR /WRO I
Write signal
(from CPU)
88 /RES /RES IS
Reset signal
(from CPU)
89 DB0 DB0 IO DATA BUS (USART)
90 DB1 DB1 IO DATA BUS (USART)
91 DB2 DB2 IO DATA BUS (USART)
92 DB3 DB3 IO DATA BUS (USART)
93 GND GND GND
94 DB4 DB4 IO DATA BUS (USART)
95 DB5 DB5 IO DATA BUS (USART)
96 DB6 DB6 IO DATA BUS (USART)
97 DB7 DB7 IO DATA BUS (USART)
98 /R /RDH O
Read signal
(to USART)
Pin
NO.
Name ER-A770 I/O Description
99 /W /WRH O
Write signal
(to USART)
100 VCC VCC +5V
101 GND GND GND
102 RES RES USART O
Reset signal
(to USART)
103 TRNCLK GND I GND
104 RCVCLK GND I GND
105 DBTST /SRCS ID
RS-232/INLINE
USART chip select
106 UTST VCC ID +5V
107 /CSA /CS1 IS USART_A chip select
108 TRNDTA TXD1 O
RS-232 transmission
data signal
109 /DTRA /DTR1 O
RS-232 data
terminal ready signal
110 /RTSA NC O NC
111 RCVDTA RCVDT1 IS
RS-232 reception
data signal
112 /CTSA GND IS GND
113 /DSRA /DSR1 IS
RS-232 data set
ready signal
114 TRNRDYA TRNRDY1 O
RS-232 data
transmission enable
signal
115 RCVRDYA RCVRDY1 O
RS-232 data reception
enable signal
116 TRNEMPA TRNEMP1 O
RS-232 transmission
buffer empty signal
117 SYCBKA BRK1 IO
Break code
detection signal
118 GND GND GND
119 /CSB /CS2 IS USART_B chip select
120 TRNDTB TXD2 O NC
121 /DTRB /DTR2 O NC
122 /RTSB NC O NC
123 RCVDTB RCVDT2 IS GND
124 /CTSB GND IS GND
125 /DSRB /DSR2 IS GND
126 TRNRDYB TRNRDY2 O NC
127 RCVRDYB RCVRDY2 O NC
128 TRNEMPB TRNEMP2 O NC
129 SYCBKB BRK2 IO NC
130 GND GND GND
131 /CSC /CS3 IS
USART_C chip
select
132 TRNDTC TXD3 O NC
133 /DTRC /DTR3 O NC
134 /RTSC /RTS3 O NC
135 RCVDTC RCVDT3 IS GND
136 /CTSC GND IS GND
137 /DSRC /DSR3 IS GND
138 TRNRDYC TRNRDY3 O NC
139 RCVRDYC RCVRDY3 O NC
140 TRNEMPC TRNEMP3 O NC
141 SYCBKC NC IO NC
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