SMT PIC programming???

[2camjohn]

I am considering using surface mount PIC chips in order to save space on my boards.


My question is:

How do you usually program a surface mount PIC?
Is there any way of programing the PIC before I solder it to the board like the through hole PICs I am using at the moment.

Or do I have to include the programming circuit in my board???
If this is the case can someone direct me to any websites concerning designing this kind of cicruitry.



Thanks
John

 

[checkmate]

The programming circuit is called ICSP. I recall it comprises of a diode on the MCLR line, a resistor, and a 5-6 pin socket. I don't have the schematics off-hand

 

[2camjohn]

Ah, sounds quite doable.

I will google for ICSP now.

I was worried I would need an eniter pic programmer built onto my circuit to program SMT PICs. :?

 

[mfratus]

pic smt programming

I went to SMT with our product line, and just took RB6, RB7, MCLR, and GND to the same pins on our DIP chip programmer. Works like a charm!
Best thing is that the board runs immediately after programming, so I can make sure my code works. Just keep the leads shorter than about a foot.

 

[checkmate]

Re: pic smt programming

I went to SMT with our product line, and just took RB6, RB7, MCLR, and GND to the same pins on our DIP chip programmer. Works like a charm!
Best thing is that the board runs immediately after programming, so I can make sure my code works. Just keep the leads shorter than about a foot.

The use of the diode mentioned earlier is to protect the circuit. During programming, the programmer has to inject voltages as high as 13V into the MCLR pin to kick the chip into programming mode. The diode prevents this voltage from spreading to the rest of the circuit.

 

[StupidDum]

Previously I used a ICD to program my chip on board and that was slow like hell. It took me 4 minutes to program a chip. Now i use ICD2, which is much much faster, very convenient during development, and also mass production.

 

[2camjohn]

Excuse my newbieness, but what is ICD and how does it relate to the subject of my thread?

Thanks
John

 

[mfratus]

back to switching from DIP to SMT PIC chips, and programming

So, what I mean is if you change your circuit to use SMT devices instead of DIP (through-hole) chips, all you need to do is run those 4 lines to whatever you used to program your chips with, to the very same SIGNAL lines (the pin numbers may change - check the chip docs). If you power up your board, then connect those 4 lines, your programming machine won't know the difference, as long as B6 and B7 are not driven by other chips. My first board had a jumper that I inserted after programming the chips, but later removed that when I realised that the B port went to chip inputs. As long as B6 and B7 are used as outputs, no need to worry. It works every day, many times a day, for me. It works just as fast as the Matrix board (from Rentron) does when a chip is directly in the board. By the way, ISP is In-System Programming, I guess ISD is In-System Debugger. I use a stand-alone PIC programmer from www.matrixmultimedia.co.uk.

 

[StupidDum]

Excuse my newbieness, but what is ICD and how does it relate to the subject of my thread?

Thanks
John

ICD is In-Circuit serial Debugger by Microchip. The program is downloaded serially using 3 pins. As its name apply, you could debug your chip on board. You could implement command like halt, stop, reset, step into, and view the internal register, memory.
Therefore, you dont need to remove your chip from board to be programmed.

ICD is the first generation that has only serial interface. It doesnt support all devices, only certain Flash devices.

ICD2 has both USB and RS232.