In Circuit programming / boot loader options?

[ShaneMichael]

Thanks for the response.
The main advantage of the boot loader is you don't need a PicKit 3 or U2 programmer after the boot loader has been flashed to the device (you still need to get the boot loader on the target device the first time). New firmware is then loaded with a serial connection. I usually have a MAX232 chip in the circuit for protection, but that's optional. To load the new firmware you just compile/program in Microcode, it will wait for the microcontroller to reset then the new code loads. Depending on code size it takes a 2-30 seconds. Basically the same functionality at the end of the day. Back when I started I used the U2. I would take the microcontroller out of the circuit, put it in the U2, flash, reinstall the microcontroller, test, repeat. After a few hundred times of that I found the boot loader which allowed in circuit programming. It worked fine all this time so I stayed with it.
The cost of the PicKit 3 is about $50 from DigiKey, so I'm going to migrate that way. I'll add the ICSP header on my board then I should be able to use any(?) microchip. I think the technicians will like this since it's USB and the program can be saved on the PicKit 3 and flashed without being connected to a PC.

[mark_s]

I'll add the ICSP header on my board then I should be able to use any(?) microchip.

As far as I know all pic families are capable of ICSP. Keep in mind that the data and clock lines are
sensitive to what you have connected to these pins during programing. So, in your design be careful
to assign these for programing only, high impedance loads or add jumpers to disconnect the load.
I learned the hard way. I had a proto pcb made which had resistor and led connected to one these pins.
I had to unsolder one side of the resistor each time I programed.

Read this even if you are using a pickit3. Good info
http://melabs.com/support/icsp.htm

[andywpg]

I think the technicians will like this since it's USB and the program can be saved on the PicKit 3 and flashed without being connected to a PC.

I absolutely LOVE the Programmer-To-Go abilities! When I was tuning the PID loops for my first version of my charcoal smoker controller, I had the smoker going in the back yard. When I wanted to change one of the gains, I would go downstairs, set it up, then just go out in the back yard, reprogram the chip in circuit, and continue testing (with DELICIOUS results at the end of the test-session!).