various DATV transmitters. The two relay boards and the
FPGA board were bought on eBay from China. The Veroboard
has an RS232 level converter chip on it. The whole thing is
controlled via a serial link. R001
as the amplifiers are some distance from the computer and
USB2 wouldn't cut it. I have implemented a simple rx UART
in Verilog which runs on the FPGA board. I may add ADC
support later so I can measure temperature, power, VSWR etc.
Using an FPGA seems a bit like overkill in this application
but the boards cost about the same as ready made PIC boards
if you are careful in your purchasing and of course they have
far more I/O on them than a PIC would have.
When I send the commands from my Linux system I can hear the
relays clicking and the right ones come on, so I know it is working.
Next I have to do some rewiring of the transmitter rack
to accomodate the new relay box. I have amplifiers for 70 cms,
23 cms, 13 cms and 9 cms so there is a lot of cabling to add.
DATV-Express is in the hands of the PCB layout guy so I have a
window to sort out my own stuff at the moment.