Update on PIC-USB boards

[eurkas]

Please need details

hi
how I can made like this no circuit design no parts on it

please any help

[Tim Williams]

Cool!

Tim

[Carl-NC]

If you want to purchase a license you can even program an area on the chip that will say "Arc-Geo Logger" found when you plug it into the USB port.

You can do that with the 4550 without paying a royalty.

[Tim Williams]

The FTDI handle ALL USB controls. Yes I program the 16f877 in the Arc-Geo logger with my boot loader installed. It's a new chip and is recommended for new projects. If you want to purchase a license you can even program an area on the chip that will say "Arc-Geo Logger" found when you plug it into the USB port.

Tim

[Carl-NC]

Tim,

It's been a while since I looked at FTDI chips, but I believe the one you mentioned is strictly a USB interface chip, and has to be connected to a micro. I suspect that this adds more complexity in communicating with the PC. Also, does it allow you to easily reprogram the micro via USB? With the 18F4550 and the code Microchip provides, everything is done for you. No chip-to-chip communication or bit-banging.

- Carl

[Tim Williams]

I understand all the features. It's sounds like a nice project. I just wanted to point out that a stand alone USB chip can do the same thing and has many ports also. I look forward to the board.

Tim

[Carl-NC]

Tim,

Please read the other thread in this forum, "The Basics of USB-PIC". It has a schematic.

The purpose of this project is to create a small (2"x2") independent circuit board that can be patched in to any design. It is basically a single chip 18F4550 micro that has a built-in USB interface, so no other chip is necessary. Here are some highlights:

• The USB-PIC board can be powered off the USB cable, up to the USB limit of 500mA.
• For higher currents, USB-PIC can be changed to an external supply.
• USB-PIC has 30 available I/O pins that can be patched into any circuit.
• The 18F4550 can run up to 48MHz.
• Once a permanent bootloader is installed, PIC firmware can be directly programmed from the USB, no special programmer required.
• PIC firmware can use the USB while it is running. You can write software for the PC that toggles a port when you click on a checkbox, or you can change firmware parameters on-the-fly. For example, if you use the PIC to create all the pulses for a PI detector, you could have PC software with a bunch of timing controls and, while the PI is running, change any of the timing parameters via USB. In short, the PC can become a programmable control panel for your detector during development.
• You can also use the USB to read information from the PIC while it is running. You could read the value of a port, or log data from the PIC's ADC.

Yes, you do have to program the bootloader using the standard PIC ICSP interface, basically 3 pins. Then it's all USB.

- Carl

[Aziz]

Hi friends,

my USB AVR programmer uses the CP2102 chip. It is an USB to UART bridge chip and quite easy to use. The USB driver installs a virtual RS232 port to access the UART interface. Any micro can be interfaced to the UART interface. Writing an applification specific USB driver software isn't trivial for amateurs. So the RS232 and UART API is easier to use and saves a lot of work and as Tim mentioned a lot of code space.

For high-speed and high bandwidth applications of course, an USB interface is a must have demand. Anyway, Carl is supporting to break the barrier of old interfaces. This could bring some interesting new applications.

I would be interested in how to realize knowledge.

Aziz

[Tim Williams]

Carl I use the FT232R - USB UART IC from

http://www.ftdichip.com/FTProducts.htm#FT232R

It works great and save code space. Plus you can use any chip.

Tim

[Tim Williams]

On my controllers the boot loader has to be programmed in the chip from a programmer before USB can be used to program the chip. Things change fast so it may be possible with the chip Carl is using.

Tim

[KingJL]

But if you have a regular PIC programmer this will be easy to do, and you only do it once. After that all programming is via USB.

Carl, I'm confused. Almost all of the in-circuit programmers use the JTAG connection to program the uPC (even the USB ones like PICKIT II). The USB shouldn't work until there is bootloader code. Although a JTAG could be kludged using the uPC header pins.
Am I mistaken? It wouldn't be a first!
Regards,
J. L. King

[Tim Williams]

Carl what is this project about? A USB programmable project board with boot loader?

Tim

[Carl-NC]

I can do a kit, for maybe $20 which is pretty close to my cost. However, the PIC won't be programmed with the bootloader... this is done after it's soldered down. But if you have a regular PIC programmer this will be easy to do, and you only do it once. After that all programming is via USB.

So here's where I'm at:

$8 -- Bare PCB only
$20 -- PCB & components
$35 -- Assembled & programmed

I got a basic read-pin function working, but there are a few quirks I need to figure out. Hopefully by the end of next week, I'll have everything ready to go.

- Carl

[bbsailor]

Carl,

I would be interested in a circuit board and a kit.

bbsailor

[Qiaozhi]

Hi Carl,

Could you also offer a kit-of-parts? i.e. the blank board + components.
If so, how much?

If no-one is interested in a kit-of-parts, then I'll go for a built one.