Load-n-Go Drive capability

Monitair · Joined: 12 Mar 2012 Posts: 4

I have a product whose Pic B7 (PGD) line is pulled up to Vdd by a 1K resistor. Does anyone know the drive capability of the Load-n-Go? Is it capable of driving 5mA@5V on PGD?

Mike Walne · Joined: 19 Feb 2004 Posts: 1785 Location: Boston Spa UK

You don't tell us which PIC, and it will be in the data sheet.

Mike

Monitair · Joined: 12 Mar 2012 Posts: 4

What difference does the PIC make? I am asking if the Load-n-Go is capable of driving (or more precisely sinking) 5mA at 5V on its PGD line.

Ttelmah · Joined: 11 Mar 2010 Posts: 19534

Why not just tell us the chip?.
It does affect things, since the input thresholds that have to be met depend on the chip, and the frequency that has to be generated is also dependant on the chip involved.
The outputs are only rated to deliver about 1mA to full Vih/Vil specs. 5mA is 'pushing it'. Howver the maximum current that can be delivered is about 6mA, so it might work.

temtronic · Posted: Thu Jun 07, 2018 1:31 pm

hmm.. I generally leave the ICSP 'dedicated' to ICSP so I was curious...

this...
If pins B6 and B7 are used in the target circuit, ensure the circuit has high impedance during the programming process.
.. right from the online load-n-go section of the CCS website

I don't consider 1K a 'high impedance' so I'd say it won't work as you want it to.....I would test though, maybe 5 different boards, each 10 times, just to confirm/deny that it works though. Testing 1 board ,2-3 times isn't good enough,especially if the equipment is in the field.

Jay

Ttelmah · Joined: 11 Mar 2010 Posts: 19534

If this was to be used generally, you'd also have to test multiple Load-N-Go units....
10K would work. 1K might.

Monitair · Joined: 12 Mar 2012 Posts: 4

Okay - thanks for your help. FYI the PIC is a 16LF1827. I have had no problems programming it with a PicKit 3 (on over 4000 units) but I thought I might be a bit more 'grown up' about it and buy a Load-n-Go which at least has an RJ connector rather than a SIL socket. I'll mod the circuit to replace the 1K with a 10K on future build.

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

You can get a SIL to RJ-11 adapter for the Pickit 3:
https://www.digikey.com/product-detail/en/microchip-technology/AC164110/AC164110-ND/1212490
It's made by Microchip.

temtronic · Posted: Fri Jun 08, 2018 5:08 am

If you decide to go the RJ45 route, be sure to buy high quality, hard gold plated RJ45s ! While you may not be using them often, you need reliable connections. Some actually have 1 or 2 LEDS in the case which may prove useful.
Should you go with the adapter cable, be sure the connections are good and not able to 'flop around'. An extra wiggle or jiggle could disrupt the download.

Jay