Icom IC-7700

3 - 6
Pin
No.
Description
IN/
OUT
Condtion
23 Clock to the EEPRROM (HN58X2464TI). O
24 Serial data from the EEPRROM (HN58X2464TI). I/O
26 Clock signal to the EEPROM (DIGISEL UNIT; CAT24WC256). O
27 Serial data from/to the EEPROM (DIGISEL UNIT; CAT24WC256). I/O
30 RTTY keying. I "H"="space" is marked
31 Transverter control signal from the [ACC] connector. I
"L"= Transverter is
activated.
21 PLL unlock signal. I "L"=Unlocked
5–
20
Address bus lines. O
73–
71
Data bus lines. I/O
84 WAIT signal (bus line control). I "L"=Wait.
85 SEND signal. O "L"=TX
86 Dual Port SRAM intrude signal. I
87 "L" indicator control signal (bus control). O "L"= lights.
88 "H" indicator control signal (bus control). O "H"= lights.
89 READ data (bus contol). O
90 Address data (bus contol). O
94 PTT/ACC SEND input. I "H"=TX
107 Squelch signal to the [ACC] connector. O
"H"= Squelch open (RX
LED lights)
109 Squelch signal. O
"L"= Squelch open (Mute
OFF)
35 External SEND (lead relay) signal output. O "H"=Relay ON
36 External SEND (IC relay) signal output. O "H"=Relay ON
37 Chip select signal to the Dual Port SRAM. O "L"=SRAM is selected.
38 Chip select signal to the expander. O
"L"= Expander is
selected.
3-4 MAIN CPU (IC604) PORT ALLOCATIONS (continued)