PIC16F1454 Connecting To USB Doesn't Work

[tumbleweed]

I don't care much for the 18F1xK50, either of them. They don't have much ram/flash resources, plus...

Why Microchip do such stupid things, like two sets of programming pins for low or high voltage?

That was done for pin-out compatibility with the 18F1xK50, but these things are a royal PITA when it comes to programming them.

The ICSPCLK and ICSPDAT lines are shared with the USB D+/D- pins and that causes all sorts of issues:

- you have to make sure to unplug the USB cable when programming
- you can't program at 5V VDD since the USB D+/D- pins have a max voltage of 3.3V, and the programmers usually use VDD to power the programming pins
The programming spec shows the addtl circuitry required (they used to have a special adapter for this)

The second set of programming pins was added to the 16F part to help overcome this.
The 18F2xK50 is much easier to deal with.

See the PIC16(L)F145X Memory Programming Specification doc DS41620C (the 13/14K50 has similar restrictions)