Is there an ICSP pinout standard???

[OldMarty]

Hi All,

As the title suggests, Is there an ICSP pinout standard???

I see the Melabs U2 programmer uses an IDC10pin header which then gets converted through various adaptors to other interfaces/boards etc.

I also see a 6pin (SIL) connector is used on microchip boards/programmers etc..

I'd prefer to use IDC10pin headers on my projects as they offer a keyed (non reversible) connection, and wonder if i should simply wire my project board(s) to the "U2" pinout wiring?
Obviously using an alternate programming device would also need to be adapted from 6pin to 10pin to keep everything inline & safe.

Your thoughts please?

[towlerg]

Is there an ICSP pinout standard??? No.
Bear in mind that you only need 5 pins for ICSP (on a PIC).

As to handing, some people use a right angle 6 pin header then its obvious which way round the Pickit2/3 (same) goes.

[longpole001]

hi , i thought i would put in my 2 cents worth on ICSP standard


a 10 pin header as per the u2 programmer is far too large to be placed on pcbs as the design gets more complex and size of the pcb gets smaller , more so when smd and clearances become harder depending on layouts

for me most cases i use only 4 pin header (2.54 spacing ) yes they are not keyed , but since the programmer is not powering the device , it just not work/program , you get a msg that the device is not ready etc and you reverse the connection ,, no damage or issues

If 5 pins are used , the programmer can power the device when programming , but for all the devices i have made, this is now very rare , and if programmer has to power the cpu is often a creates a bigger issues such as

a. if the device is not 5v,then it cant be used directly so no standard can be applied to the header
b. if cpu uses the common power bus for the pcb so that the programmer would need to supply the total current / voltage for the pcb when programming - easy way to damage a programmer
c. requires that the programmer interface be be keyed to avoid possible damage to the programmer / pcb device when it supplies power

As a result it often is not advisable to use the programmer to power the cpu when programming via ICSP and maintain a standard

consider standardizing on the ICSP header connection pinouts for ALL your projects and make the interface as small as practical , also making them able to support both vertical / horz mounted INTERFACE options , that are easy to swap to allow for PCB layouts that will not work well if vert or horz ones may not suit easy , or need to be put on the reverse side of the pcb if need be

also 2.54 headers can be vert/ horz, mounted and available in colors so you can use say red as the ICSP

for me i assign 4 pin 2.54 header as
pin1 = GND
pin2 = PGD
Pin3 = PGC
pin4= VPP/MCLR

for me the grouping made sense when pin1 is often square and is grd
PGD and PBC are often in the same seq on the chip and line up on the pcb
VPP/MCLR also are often the next pin on the cpu so line up on the pcb

for what is worth

Cheers

Sheldon

[OldMarty]

Thanks Sheldon, makes perfect sense.


Yes, i had no intention of using the VCC to provide power to the chip, so i was down to 4 pins myself ;-)

I guess i can use an indexed 4pin header so there's no chance of reversal, as opposed to a naked S.I.L header which can be a 50/50 chance of getting it right ;-(

Regards,
Marty.

[pedja089]

I use 5 pin, so PIC Kit can be directly plugged in. And one of advantage of using 5 pin is that ground is in middle, so even if you reverse connector there is no reverse polarity.

[richard]

ditto for 5 pin

[OldMarty]

I use 5 pin, so PIC Kit can be directly plugged in. And one of advantage of using 5 pin is that ground is in middle, so even if you reverse connector there is no reverse polarity.
I'd be concerned about potentially driving 13volts/Mclr onto the PGC/D pin if the 5pin header was reversed ;-(

I think the ultimate solution for a non-keyed connector would be using an 8pin socket, wiring the pins with opposing pairs of signals so a backwards fitted header would still be correct signals into the PIC.

e.g.

pins:
1 - GND
2 - PGC
3 - PGD
4 - VPP/Mclr
5 - VPP/Mclr
6 - PGD
7 - PGC
8 - GND

For me, i think i'll settle for a 4 pin KEYED header plug/socket. ;-)

[richard]

I'd be concerned about potentially driving 13volts/Mclr onto the PGC/D pin if the 5pin header was reversed

can't happen with pk2 or pk3 those devices always ident chip and test voltage levels before pgm activity takes place

[pedja089]

Even if it try, current is low, and PIC esd diode should clamp max voltage on pin to Vdd+0.3V. So nothing to worry.

[tumbleweed]

i had no intention of using the VCC to provide power to the chip, so i was down to 4 pins myself
Even if you're not going to power the chip via ICSP it's important to provide the VDD connection.

That way the programmer can detect the target voltage, and for some programmers like the PK3 it uses that
target voltage to control the output voltage of the ICSPCLK and ICSPDAT signals.

This is esp. important if you work at lower voltages.

[pedja089]

You can set PK3 to supply same voltage as system, so pgd/pgc voltage should be OK. But again, 5 way pin header worked for me many years, so I don't see problem with that.
Recently I had small board with weird shape, and there was no room for 5 pin in row.
So I tried this
http://www.microchip.com/Developmenttools/ProductDetails.aspx?PartNO=TC2030-MCP
It is ok.

[technotronix]

Are you taking about ISO or ISP standards??

[Dave]

As far as I can see over the last 10 or 15 years there is NO industry standard persay. There are a few pinouts that have been adopted by certain manufactures. There is an RJ45 pinout that Microchip uses for it's programmers and has adopted it as a sort of standard. Also there is an 6 pin SIL connector arrangement used for the PK2 and PK3 programmers. I place that one on all of my SMT projects. Also there are a few company's that make "TAG" programmer adapters intended for SMT programming. The pinouts are all different for the different micro mfr's. so there is NO ISO standard. Usually the micro mfr. will somewhat standardize on a pinout for there particular product and development systems.