I am making some progress toward a manufacturable design of my RS232 baud rate converter. I now have the prototype working.

As you can see from the photo, I had to add a couple of wires to the PCB but only a couple and I am very pleased about that!

I am going to revise the board design before sending it for manufacture – apart from the couple of patches I also forgot to bring out the chip programming lines and the reset line. These are not needed for normal operation but will be needed to initially program the chip. To this end I am putting a new 10-way header on the board for programming and debugging.

Another issue I had when bringing the thing from prototype to a production stage was the firmware. I realized there really should be some way for end users to update the firmware either to patch bugs or add new features when customers inevitably request them. I do not want to be physically mailing these things back and forth for modification once they are sold. To that end, I have written a boot loader and firmware update utility.

I’m now ready to get the board manufactured. I want to do a small run of 20 or so to start off with. I used BatchPCB for my prototype but they are not cost-effective for more than one or two boards. After comparing a few different places, I have also come to the conclusion that local Australian PCB manufacturers are 3 to 4 times the price of an offshore fab. So I am going to try a Chinese manufacturer.