Electronics > KiCad

Do I need to move to a 4 layer PCB

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asmi:
Nowadays I always go for at least 4 layer PCBs because my time and sanity is worth more to me than the price difference between 2 and 4 layer PCBs. Once you get power and ground out of contest for routing space, things tend to become much easier.

TomS_:

--- Quote from: newtekuser on March 06, 2023, 01:57:18 am ---Problem solved! As suggested, I reassigned some pins and was able to route everything. :-+

--- End quote ---
I hope you've checked the datasheet to be sure the functions you are using are available on the pins you have chosen.

The 16F887 is an oooooold PIC that very much pre-dates remappable IOs, so not all functions are available on all pins...

Newer families don't seem to have any peripherals that can't be remapped last time I looked, I was somewhat surprised. If you can switch to something more modern it would be very much recommended by a lot of people I'm sure...

mikeselectricstuff:

--- Quote ---Newer families don't seem to have any peripherals that can't be remapped last time I looked, I was somewhat surprised. If you can switch to something more modern it would be very much recommended by a lot of people I'm sure...

--- End quote ---
This does vary between parts - some parts can map pretty much anything to anything  some have restrictions, and restriction types differ between families
e.g. on the 32MM, only the second peripheral (UART2, SPI2  etc.) can be remapped
On the 16F1535x, most peripherals can only map to only two  of the three port groups (porta,b,c) , and the useable ports vary between peripherals
On the 32MX1xx each peripheral can only map to 1 of up to 8 pins. Except SCLKs Choosing which peripheral (Uart1/2 etc.) to use effectively doubles the choice, but if you're using a lot of peripherals, very careful planning is needed.
PIC24F can map pretty much anything to anything ( except I2C)

There is usually no reason to use the older PICs- the more recent ones are generally better in all respects and cheaper. Availability seems to be getting pretty good again.

woofy:
PPS is great in the latest controllers, but if there is another feature I'd like to see its an internal matrix to route peripherals internally. In a recent design I needed to route a CLC output to a UART Rx. It's possible to route the CLC output to a pin and use the same pin for Rx, but an internal connection would have been nicer, saving a used but otherwise unconnected port pin.

newtekuser:
I did try to move my project to a PIC18 family but had some issues getting things to work the same as on the 887 and gave up. However, I do intend to pick this up again with the 18F at some point as the parts are cheaper.

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