MAX3421E to PIC18F4550

urefowei schrieb:

I suggest using the Atmel AT90USB1287. It's more popular, well documented, and Atmel provides several libs.

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Mit freundlichen Grüßen

Dipl.-Ing. Frank-Christian Krügel
Reply to
Frank-Christian Krügel
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we do not have time to change.. it was said that we can use a special type of solder for this..

Reply to
urefowei

Yes, you can use solder paste and stencil.

Next question is: How do I build the stencil?

Answer is: You build with the PCB design.

Next Next question is: How do I build the PCB.

Reply to
linnix

can we also use a hot air solder?? we are also trying to contact maxim and ask for a socket, we dont have a reply yet.

Reply to
urefowei

Yes, hot air soldering is common for prototypes. I don't think Maxim will be able to provide you with a socket. There are likely adapters available from a few companies that make that sort of thing. But you still have to solder the part to the adapter. You can have an assembly house solder them for you. I have had QFN parts hand soldered even with a thermal pad on the bottom. I think they did the pins with an iron, and then used hot air to melt the paste under the pad. But they did have to use paste rather than wire solder.

Rick

Reply to
rickman

Use this prototype adapter:

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google "smt hand soldering" there are lots of articles and examples

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Joe Chisolm
Marble Falls, TX
Reply to
Joe Chisolm

a

I've hand soldered a few QFN chips that did not required connection to the thermal pad. I have also wondered if you could hand-solder to the thermal pad by putting one or more large vias in the thermal pad, then applying solder from the bottom through the via(s). Has anyone done anything like that?=20

Mark Borgerson

Reply to
Mark Borgerson

I've done that.

I think there is a theoretical danger of all the solder running out through the hole. Then again many application notes have multiple thermal vias in the pad anyway. ISTR recommended solder paste patterns, made up of 9 or so little squares with a via in the middle of each one.

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John Devereux
Reply to
John Devereux

We place 4 small vias to secure the pad of a 64pins QFN, then tin it with some solder on top, before placing the chip on it. We have a few hundreds of them in use, and they are holding so far. The device is subject to around 50g on impact during field test.

Reply to
linnix

whats best to use?? i mean, the PCB.. what particular PCB is best suited for our design especially dealing with a TQFP..?

Reply to
urefowei

I can't say I understand the question. What types of PCB do you think there are?

You can have a custom PWB made which will cost a few bucks, but typically not prohibitive. You will then need to solder a TQFP, but that can be done by hand with a moderate amount of skill. If you don't want to pay the money for a custom PWB, you can buy adapters that will let you solder the TQFP on it and will then fit a 0.1" spaced perf board either for point to point wiring or wire wrap. If the soldering is a problem, you can get people to do the soldering for you.

The last few posts before yours were discussing soldering leadless chips such as QFN packages. These tend to be very small pitch and have no leads, so that it can be a bit tricky to get good solder joints without paste, but it can be done. But a TQFP is a leaded part which is much easier to work with.

Is this what you are asking? Am I misunderstanding your question?

Rick

Reply to
rickman

hi rick..

thank you for the advices.. we really appreciate them.. we are happy to here that we made a good choice between TQFP and QFN..

we understand all your insights, thank you so much!

Reply to
urefowei

thanks everyone, we are almost through the hardware, now comes the firmware design..

We got codes from the MAXUSBLAB10 appnote of maxim website..

What is SSPDR, SSPSR, etc??

We wanna use this codes and integrate them with our PIC18F4550..

Please help us

Reply to
urefowei

Greetings Everyone, I would like to have some inquiries regarding PIC18F4550.. I found a header file on the MCC18 compiler h lib folder, p18f4550.. Is this the header file that contains the register of PIC18F4550?

If so, how do I use this registers on a program.. Somehow, I did.. I found this code on MAXUSBLAB10 at maxim website which uses LPC as MCU..

originally, the code goes like this with SSPDR, SSPSR, SSP_BSY

void Hwreg(BYTE reg, BYTE val) // write a host register { HSSEL_LO SSPDR = reg+0x02; // command byte into the FIFO. 0x02 is the write bit SSPDR = val; // data byte into the FIFO while(SSPSR & SSP_BSY) ; // hang until BUSY bit goes low HSSEL_HI }

This is how I revised it using SSPBUF..

void Hwreg(BYTE reg, BYTE val) // write a host register { HSSEL_LO SSPBUF = reg+0x02; // command byte into the FIFO. 0x02 is the write bit SSPBUF = val; // data byte into the FIFO HSSEL_HI }

the SSPBUF is declared in the header as

extern volatile near unsigned char SSPBUF;

But, it return an error (syntax error) on SSPBUF..

Whats wrong?

Reply to
urefowei

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