On-board programming with easy PDK Programmer: Possible?

[ragnarrhomb]

In the PFS-datasheet section 9.2.8 they have this example (when writing with their tool):

But the Easy PDK programmer does also have lines to PA0, PA4 and PA7. Is that necessary?

[JustinOng]

According to this, PA4 is used for calibration of IHRC.

[ragnarrhomb]

Ahh! Thanks for the catch! Do you know about "the limit" of usage of this pin to other things "in circuit" ?

[JustinOng]

This is pure speculation on my end: so your as your circuit does not excessively load the pin, you should be alright.

Of course, this comes with a whole long list of caveats - for example, in my application, I have PA4 connected to a MOSFET controlling a small vibration motor. Trying to program and calibrate a PFS172 while the motor is connected results in failure, which I believe is caused by the power rail browning out.

I would strongly suggest that you test your intended circuit to confirm for yourself whether it'll work in your application.