by Steve Anderson » Tue Aug 08, 2017 5:42 pm
For those contemplating building this there's very few, actually no, specialist parts required.
The exception is the two pic microcontrollers, buying blank ones is no problem but I will need to program them with the firmware. I can get them here at a better price than the UK, burn them and send them on. Alternatively if you can burn your own micros I'll e-mail the .hex file. Check your software (or whatever) can burn PIC18F25K20s with High-voltage programming. The LVP pin is used as an I/O.
Harry has had a bit of a problem with getting 8-pin DIP versions of the 23LC1024 RAM chips. He's ordered SOIC versions and some 8-pin SOIC-to-DIP adapter boards. Futurelec Australia have them, I'm sure there'll be a supplier in the UK. SOIC has a pin spacing of 1.27mm, half the usual 2.54mm (0.1"). With a fine-tipped soldering iron these can be assembled quite easily, anything smaller is a no-no for me.
It's too early to publish a parts list although some 90%+ are defined. No precision parts, Rs & Cs can all be 5% or better, make sure you have plenty of 100n disk-ceramic capacitors. I suggest using sockets for all chips, there's bound to be updates to the micros now and then.
As mentioned before, if I can get to grips with Eagle a PCB may be available too.
Steve A.
- Attachments
-
- 8PINSOIC_TO_DIP8.jpg (37.98 KiB) Viewed 13185 times