phastmike / rs8k_aprs

PIC code to convert Shipmate RS 8000 Radio for use in APRS

Convert RS8000 for use in APRS

This is the assembly code for PIC16F84 which will convert the Shipmate RS 8000 Radio PLL for use in APRS.

It was done in 2007.

Solution

After an inital analysis it was verified that only 7 bits would change to synthesize two APRS frequencies, 144.8 and 144.85 MHz.

• PORTB is then used to supply the needed bits.
• PORTA is used to monitor PTT and channel changes.

The PIC is running a loop checking the inputs (PTT and Channel) and setting the corresponding PLL values.

More info

; PIC16F84A 4MHz
; 
; 
;                      +-------  -------+  
;                      |       \/       |
;                RA2 --+ 1           18 +-- RA1           +----+
;                      |                |                 |   _|_
;                RA3 --+ 2*          17 +-- RA0     33pf ===  \_/
;                      |                |                 |
;         RA4/T0CLKI --+ 3           16 +-- OSC1/CLKIN ---+
;                      |                |               [XXX] 4MHz xtal
;              !MCLR --+ 4           15 +-- OSC2/CLKOUT --+
;                      |                |                 |
;                Vss --+ 5           14 +-- Vdd          === 33pf
;                      |                |                _|_
;                RB0 --+ 6          *13 +-- RB7          \_/
;                      |                |
;                RB1 --+ 7           12 +-- RB6
;                      |                |
;                RB2 --+ 8           11 +-- RB5
;                      |                |
;                RB3 --+ 9           10 +-- RB4
;                      |  (PIC16F84A)   |
;                      +----------------+
;
;
; Outputs
; 
; RB0 1 2 3 4 5 6 7_ Channel indicator (Active Low)
;   | | | | | | \___ M16
;   | | | | |  \____ M8
;   | | | |  \______ A64
;   | | |  \________ A32
;   | |  \__________ A16
;   |  \____________ A8
;    \______________ A4
;
;
; Inputs 
;
; RA2 _ PTT (Active Low RX=1 TX=0)
; RA1 _ Channel switch 

TODO

• Add schematic
• Add screenshots?