E.F. Johnson Company 7780 Series, Preliminary Service Manual, Page: 70 / 116

CIRCUIT DESCRIPTION
4-6
November 1999
Part No. 001-7780-500
Table 4-1 Microprocessor IC306 Pin Descriptions
Pin
Name
Port Name
Input or
Output
Description
Active High
or Low
1 RES Input Reset pulse input -
2 XTAL Input System clock connection terminal -
3 EXTAL Input System clock connection terminal -
4 FWE Input Not used -
5 MDI Input Flash ROM data import control (L=load) Low
6 MDO - Not used -
7 NMI - Not used (external pull-up) -
8 STBY - Not used -
9 VCC - Supply voltage -
10 CSHIFT Output Clock shift control (H=shift) High
11 - - Not used -
12 INTS I/O - -
13 RxD - Not used (external pull-up) -
14 TxD - Not used (external pull-up) -
15 VSS - Ground -
16 DTMFSO Output Segment data for LCD driver -
17 EXTDC Input Option signal input -
18 DTMFCK Output Clock signal for LDC driver -
19 - - - -
20 FCN Input FCN button switch Low
21 AUX Input AUX button switch Low
22 DPOTST Output Digi-pot strobe signal -
23 OFFREQI Input Main voltage supply switch Low
24 QSELOI Input Channel select switch input -
25 - - - -
26 SN_RX Input SMARTNET receive data input -
27 TXDATA Output Subaudible tone/main audio signal out -
28 RXDATA Input Receive data input -
29 BWC Output Transmit/receive data filter bandwidth signal output High
30 KEYR3 Input Key matrix scan in -
31 KeyR2 Input Key matrix scan in -
32 NOISE Input Noise pulse input/squelch control -
33 MMUTE Output Mutes microphone audio signal (L=mute) Low
34 TXPREC Output Subaudible signaling tone/damp signal output -
35 TEST Output Bypass transmit data filter (H=Normal/no bypass) High
36 L5V - Supply voltage -
37 L5V - Supply voltage -
38 BATIN Input Low battery voltage detection -
39 RSSI Input RSSI (Receive Signal Strength Indicator) -
40 - - - -
41 - - - -
42 - - - -
43 - - - -
44 - - - -
45 - - - -
46 VSS - Ground -