GPS receiver
I have been using Kenwood THD7 for many years. It is truly a wonderful piece of hardware, however it does not have a GPS receiver built-in. For this reason an external receiver has to be used.
THD7 supports GPS NMEA data at 4800bps only. In addition it has to be RS232 standard.
In order to get some GPS receiver's default baud rate set to 4800bps, I had to modify its settings as follows:
$PSRF100,1,4800,8,1,0*0E
ATmega8A is used to do the job, when the receiver is switched on.
Kenwood THD7
pictures
GPS module testing with USB (3.3V to 5V USB translation)
PCB design
PCB design
PCB prototype testing
PCB prototype testing
almost ready...
it really works :)
After many years of working with Kenwood THD7, I decided to get rid of RS232 voltage converter between radio's microcontrollers and GPS and PC output.
I am now using a standard 3V GPS module, which can be plugged in directly.
pictures
Kenwood THD7 inside
RS232 chip (ADM3202) is located above the keypad
voltage converter is disabled and patched
Hardware and software is self-made :)