Icom IC-R7O Maintenance Manual page 21

4. 1st loop
Here, after 1/10 frequency division, it is fed to pin 12 of IC2.
Frequency PLL.N Oscillation MIX output
(MHz) frequency (MHz) (MHz)
+ = a
0~79 396 ~ 475 [roasts ~ 78.4514)
Remarks
39.6 ~ 47.5 | Oscillation frequency = 2nd loop +
0.01 x N x 10
- eee iS es eae
8.0 ~ 14.9 476 ~ 545 78.4515 ~ 85.4514| 47.6 ~ 54.5
i [
+ —-- 2 nd loop: 30.8515 ~ 30.9514 MHz
54.6 ~ 61.5 N changes 1 for each 100-kHz change
of display frequency.
15.0 ~ 21.9 |a6.4515 ~ ana
22.0 ~ 29.9 616 ~ 695 92,4515 ~ 100.4514| 61.6 ~ 69.5
5-4 LOGIC UNIT
This unit controls the frequency, processes the band signals and mode signals, outputs data to the PLL,
etc, and is designed for low power consumption and high speed operation by using a CMOS 4-bit CPU.
1. CPU
IC14 is the CPU, in a 42-pin plastic package.
Pin 1 and pin 42, CL, and Clo, are the clock terminals for this CPU, oscillating about 400 kHz with a
ceralock (ceramic oscillation unit). This CPU has 9 input/output ports, each sharing its own function.
A port 4-bit input
As shown in the matrix table, decodes E port output to expand input functions with time sharing.
B port 4-bit output
Used for band-pass filter switching.
D port 4-bit input/output
Used as input/output terminal for external remote-control.
E port 4-bit output
Outputs various data as a general-purpose output terminal.
F port 4-bit output
Fy ... Strobe signal output for display.
F, ... Load signal output for PLL above 100 kHz digit.
F, ... Load signal output for PLL below 100 kHz digit.
F3 ... Relay-drive output
G port 4-bit output
PLL digit designating output