USB Programmer using PIC18F2455 - Electronic Circuits Projects Diagrams Free

kasamiko · 11th October 2007, 12:30 PM

Hi,

I'm looking for a USB PIC programmer designed using PIC18F2455 with no other fancy parts..

Parts on hand right now:

PIC18F2455
4,8,16mhz xtal..

I've seen the GTP-lite but uses 20Mhz xtal which i can't find in our place. another is the PCISquirt but uses MAX662 another hard to find components..

I need your suggestions or maybe some link for simplier design..

TIA

superbrew · 11th October 2007, 02:12 PM

Something like these?

PIC Programmers

blueroomelectronics · 11th October 2007, 02:29 PM

Do you have source code for either programmer? I'm not certain but I think the GTB-lite uses a 18F2550 and does not publish their firmware.

Good new is all of those crystal will work with USB, you'll have to set the config fuses as indicated on page 30 of the 18F2455 datasheet to set the PLLs

Without decent access to parts building a USB programmer might be tricky, I'm putting together a PICkit 2 compatible which is a fairly straight forward design, the pair of MOSFETs might not be easy to source but are actually optional the rest of the parts are common. It is designed for a 20MHz crystal but if you're interested and since Microchip posts the firmware I could try a mod it for a 4, 8 or 16MHz crystal for you.

This basic version works and is the 4 transistor (no BS250 or 2N7000 MOSFETs) I used a 18F4550 as it's what I hand on hand at the time.

skyhawk · 11th October 2007, 07:29 PM

The MAX662 is just used to generate VPP from 5V. It can be replaced with a 12-13V source. The PICSQUIRT does not switch the target VDD so it can't do VPP before VDD. If that's not an issue for you, then PICSQUIRT looks fine.

kasamiko · 12th October 2007, 03:04 AM

Quote:

Originally Posted by blueroomelectronics

Do you have source code for either programmer? I'm not certain but I think the GTB-lite uses a 18F2550 and does not publish their firmware.

I got the firmware for GTB Lite version and also for the PICSquirt

Quote:

It is designed for a 20MHz crystal but if you're interested and since Microchip posts the firmware I could try a mod it for a 4, 8 or 16MHz crystal for you.

Please sir if you can revised the code to accept either 8 or 16mhz xtal..

Quote:

This basic version works and is the 4 transistor (no BS250 or 2N7000 MOSFETs) I used a 18F4550 as it's what I hand on hand at the time.

Good to see this!! I got 1 PIC18F4550-I/P..I'll try this out...

@skyhawk

Meaning I can directly replace MAX662 with a regulated 12VDC?

Regards to all

blueroomelectronics · 12th October 2007, 07:07 AM

Do you want to use 4, 8 or 16MHz?

kasamiko · 12th October 2007, 08:42 AM

I'm planning to used 8Mhz..

Where can I get the complete projects? Schematic, pcb layout and firmware?

Regards

skyhawk · 12th October 2007, 01:10 PM

Quote:

Meaning I can directly replace MAX662 with a regulated 12VDC?

Yes. However, VPP for a number of PIC's is in the 12.5V-13.5V range; therefore, commonly one and sometimes two diodes are placed in the ground leg of the regulator to raise the output to the 12.7V-13.4V range.

One issue with building "smart" programmers is the need for another programmer to initially get some code (bootloader) into PIC chip used in the programmer.

blueroomelectronics · 12th October 2007, 02:45 PM

Quote:

Originally Posted by kasamiko

I'm planning to used 8Mhz..

Where can I get the complete projects? Schematic, pcb layout and firmware?

Regards

For my kits I never give away the PCB layout, but the schematics will be available.

The complete PICkit 2 schematic is in the PICkit 2 user manual on Microchips web site, the firmware PK2V0210000.HEX is part of the PICkit 2 software package.

I'll post an 8MHz patch of the PK2V0210000.HEX, but since it's possible for the 18F2550 series to access its config registers any firmware updates could make the programmer non functional. Your best bet is get a 20MHz crystal.

kasamiko · 17th October 2007, 03:38 AM

Quote:

Originally Posted by blueroomelectronics

....Your best bet is get a 20MHz crystal.

That will make both our life more easier..

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11th October 2007, 12:30 PM	(permalink)
kasamiko	USB Programmer using PIC18F2455 Hi, I'm looking for a USB PIC programmer designed using PIC18F2455 with no other fancy parts.. Parts on hand right now: PIC18F2455 4,8,16mhz xtal.. I've seen the GTP-lite but uses 20Mhz xtal which i can't find in our place. another is the PCISquirt but uses MAX662 another hard to find components.. I need your suggestions or maybe some link for simplier design.. TIA __________________ to err is human, to really mess things up, use a computer!

11th October 2007, 02:12 PM	(permalink)
superbrew	Something like these? PIC Programmers

11th October 2007, 02:29 PM	(permalink)
blueroomelectronics	Do you have source code for either programmer? I'm not certain but I think the GTB-lite uses a 18F2550 and does not publish their firmware. Good new is all of those crystal will work with USB, you'll have to set the config fuses as indicated on page 30 of the 18F2455 datasheet to set the PLLs Without decent access to parts building a USB programmer might be tricky, I'm putting together a PICkit 2 compatible which is a fairly straight forward design, the pair of MOSFETs might not be easy to source but are actually optional the rest of the parts are common. It is designed for a 20MHz crystal but if you're interested and since Microchip posts the firmware I could try a mod it for a 4, 8 or 16MHz crystal for you. This basic version works and is the 4 transistor (no BS250 or 2N7000 MOSFETs) I used a 18F4550 as it's what I hand on hand at the time. __________________ Bill Smart Kits build Smart People http://www.blueroomelectronics.com Last edited by blueroomelectronics; 17th October 2007 at 05:59 AM.

11th October 2007, 07:29 PM	(permalink)
skyhawk	The MAX662 is just used to generate VPP from 5V. It can be replaced with a 12-13V source. The PICSQUIRT does not switch the target VDD so it can't do VPP before VDD. If that's not an issue for you, then PICSQUIRT looks fine.

12th October 2007, 07:07 AM	(permalink)
blueroomelectronics	Do you want to use 4, 8 or 16MHz? __________________ Bill Smart Kits build Smart People http://www.blueroomelectronics.com

12th October 2007, 08:42 AM	(permalink)
kasamiko	I'm planning to used 8Mhz.. Where can I get the complete projects? Schematic, pcb layout and firmware? Regards __________________ to err is human, to really mess things up, use a computer!