Usb <-> Rs485

[Kryten]

Yeh one other thing to ask:

Would it be possible to make a ICD2 for USB using a 18F4550 ( or similar pic with USB)?

 

[Ubergeek63]

Can't do it with an FT232 either.

Missed this one yesterday...true enough, but for $11 for the VNC1 instead of $6 for the FT232 you can.

 

[petrv]

SOICs are not that bad, but take SSOP or TSSOP or even the fine-pitch QFP (0.5mm) - but I did that as well (TSSOP) - just use a lot of flux and not too much solder and it will be ok.

USB host controller and PIC - there is very new MCU from Microchip supporting USB 2.0 OTG (quite late, Atmel has such MCU for a long time).

Try look at PIC24FJ64GB106 to PIC24FJ256GB110 family.

 

[Ubergeek63]

looks like you MIGHT be able to drive a printer with that one. (today's printers are notorious for offloading processing onto the host driver software) I do not, however, see mass storage support: only a comment about minimal host funtionality.

 

[arhi]

Would it be possible to make a ICD2 for USB using a 18F4550 ( or similar pic with USB)?

I tried .. I recompiled the bootloader for 18F4550 (actually, in MLAB just changed device to 18F4550 and click on build), I then programmed the bootloader to easyPic4 board, connected it to the eth, started pickit2 app, it said I need firmware, it downloaded firmware from the net and uploaded it to the easypic4 18f4550 .. I tried using few options and it "works" .. the rs232 works, the "logic probe" works (I just had to short few pins on port A I think (not sure) .. but, basically, I just recompiled bootloader, and the firmware for 18F2550 worked .. I do not know how compatible those 2 are, and if debugging would actually work, but "initial trial" went nice

 

[arhi]

Missed this one yesterday...true enough, but for $11 for the VNC1 instead of $6 for the FT232 you can.

ah, can you please point out to the VNC1 datasheet, I have never heard about it and google just presented bunch of vnc application clones

 

[Ubergeek63]

http://www.vinculum.com/documents/datasheets/DS_VNC1L-1A.pdf

Available through Mouser

 

[blueroomelectronics]

Yeh one other thing to ask:

Would it be possible to make a ICD2 for USB using a 18F4550 ( or similar pic with USB)?

You can but you also need the 16F877 part. See my Unicorn and Inchworm+ combo. That's how it's done. You can build the PICkit2 with just a 18F4550, much better for most things than the ICD2 anyway (unless you're into dsPICs)

The PICkit2 to RS232 stuff can be found here
**broken link removed**

 

[Kryten]

So you cant eliminate the 16fXXX for ICD2. I mean arent the 18F4550 bigenought to handel both the ICD2 task as well as doing programming? Or will you simply use the 18F4550 as a USB <-> RS232 adaptor?

 

[blueroomelectronics]

So you cant eliminate the 16fXXX for ICD2. I mean arent the 18F4550 bigenought to handel both the ICD2 task as well as doing programming? Or will you simply use the 18F4550 as a USB <-> RS232 adaptor?

Nope you need both, it's an older design and the 18F4550 was brought in to replace the Cypress USB IC that was discontinued.

What's wrong with the PICkit2 ? for the PICs it supports and that's plenty it's as fast as the ICD2, programs, debugs, logic analyzer, UART tool...

 

[Kryten]

No im just asking... (looking to upgrad the ICD2 clone i built)

 

[blueroomelectronics]

No im just asking... (looking to upgrad the ICD2 clone i built)

Not worth it. You'll need to connect the PSP port on the 16F877 to the PSP on the 18F4550. That's why the Inchworm+ has that big connector on the bottom.

 

[Kryten]

Ahh ok so its not just a case of changing the RS232 for the PIC18F4550 and using those four lines to communicate..

Well Im still going to make that USB<->RS485 adaptor so thanks for all the help