I'm developing a open source watch and my schematic looks good so far.
but designing the PCB is difficult as I've only designed one real PCB before and that was using through hole components.
This PCB is using rather small SMD parts and I would like your feedback on it as I would really like some expert advise on it.
Parts used:
PIC24FJ64GB004
MCP73833
TC1071
Nokia 6100 LCD
Right-Angled Buttons.
Li+ 110mAh battery
Notes:
TC1071 is a low power adjustable LDO.
MCP73833 is a Li-ion battery charger.
The 8pin header on the left is a header to a wireless transceiver.
On the board, the LCD is on the bottom while everything else is on the top.
That's a good question Mike lol, I have a PicKit3 coming in the mail very soon that I will use, but how should I connect it?
I only need to program the PIC once as It will be using a USB boot loader so I don't really want to solder a 5 pin header to the board
That's a good question Mike lol, I have a PicKit3 coming in the mail very soon that I will use, but how should I connect it?
I only need to program the PIC once as It will be using a USB boot loader so I don't really want to solder a 5 pin header to the board
How about leaving pads for the programming leads and making a cable which is soldered to the board to program, then de-soldered and removed?
Edit: Great thread, by the way.
You might think about putting the ICSP pins on a bit of PCB that can be snapped off after the PIC has been programmed. If you use a boot loaded you only have to program the chip via the ISCP once. Keep the ICSP attached during development.
I've done a lil bit of research into power requirements (no idea why I didn't do this in the first place) and found that the LCD draws quite a lot of power.
So, the LCD Vdd pins will be behind a transistor controlled by the uC so the LCD can be switched off when not in use. But...
The LED back light requires 7V and is recommended to use 40mA... my Li-ion battery only outputs 3.7V so this is a no-no
I'm going to research into LED drivers and hopefully find a solution that's power efficient
Hi Roman your idea is ok.But for me the design is a complete waste of time.The parts are unfamiliar,too hard to find & very expensive.Its too much for a clock.
When it comes to open source there should be minimum of parts & must be available in all over the world.
May be I'm wrong tell what are the options you have in your clock?