PIC18F14K50 recognizing problems - Page 1
Forum section: electronics / general

author: House91320
author_rank: Regular Contributor
timestamp: June 09, 2013, 07:58:26 pm
content: I'm having a heck of a time getting a pickit 3 to recognize a PIC18F14K50, the weird thing is, when I removed it from the circuit I was able to program it, I've included a picture of the circuit. I had to wire mcler to the pickit, so I don't think its that.

author: Andy Watson
author_rank: Super Contributor
timestamp: June 09, 2013, 08:40:05 pm
content: I've not used the 18F14K50, but assuming it has a similar programming interface to the 16Fxxx series there will be a five-wire interface that allows it to talk to the programming kit (PICKIT3) - two power lines, the MCLR/VPP and a pair of clock and data lines. If you trace out the details you will probably find a sixth wire. On the 16F series (and others) this is labelled as the debug and/or Low Voltage Programming pin¹. This pin must not be allowed to float during programming - I believe it needs pulling down.Edit:1. Appears to be called RC3/PGM on the 18F14K50. Try pulling it down with ~10k.

author: Baliszoft
author_rank: Frequent Contributor
timestamp: June 09, 2013, 08:44:49 pm
content: I am using this pic in one of my designs and it works ok. I cant see your icsp header on your picture, be sure to connect the mclr pin, too. Also disconnect the device from the usb D+ and - while programming.

author: Baliszoft
author_rank: Frequent Contributor
timestamp: June 09, 2013, 08:52:48 pm
content: +1 hint: connect the vbus to an input (with a pulldown and current limiting resistor), so your firmware can detect the usb connection.

author: David_AVD
author_rank: Super Contributor
timestamp: June 09, 2013, 10:24:12 pm
content: You're not trying to use the ICSP and USB connections at the same time are you?

author: House91320
author_rank: Regular Contributor
timestamp: June 09, 2013, 10:26:37 pm
content: No, there is a usb connector soldered, but it isn't pluged into usb

author: David_AVD
author_rank: Super Contributor
timestamp: June 09, 2013, 10:31:32 pm
content: So you have MCLR, +5, 0V, PGC and PGD all going to the ICSP header?I've used that chip before and had no issues with ICSP.

author: House91320
author_rank: Regular Contributor
timestamp: June 09, 2013, 10:32:03 pm
content: yes

author: David_AVD
author_rank: Super Contributor
timestamp: June 09, 2013, 10:34:37 pm
content: Maybe remove the resistor on MCLR. I think I just used the internal pull-up (or 10K at the lowest) on my design.

author: Skimask
author_rank: Super Contributor
timestamp: June 10, 2013, 12:23:13 am
content: And the O/P has V3.3 at the PIC before attempting to program it?

author: David_AVD
author_rank: Super Contributor
timestamp: June 10, 2013, 12:28:23 am
content: Oops, I missed that he was running the PIC at 3.3V, so it will be 3.3V (not 5V) on the ICSP connector of course.

author: Skimask
author_rank: Super Contributor
timestamp: June 10, 2013, 12:40:10 am
content: And, unlike the PK2, the PK3 likes the PIC to have power on it before it'll think about programming.

author: David_AVD
author_rank: Super Contributor
timestamp: June 10, 2013, 12:59:59 am
content: On my project, I used the PicKit3 to power the PIC during programming. I don't recall if I tried ICSP with the board powered up by itself.

author: House91320
author_rank: Regular Contributor
timestamp: June 16, 2013, 03:48:55 am
content: Solved it, headers on my pickit were dead, replaced them, and everything is working.