Nuts and Volts - January 2009

THE DESIGN CYCLE

Screenshot 3 tells the story. The alternate Flash drive worked. The reset operation caused the version to be displayed, followed by an on-line indication. Next, you can see the sync characters being acknowledged. The carriage return that I issued after the sync() function call forced the NO Disk message.

Here's where I sucked it up and issued a real VDIP2 monitor command. The firmware version of the VNC1L is returned when the character set FWV followed by a carriage return is issued to the VDIP2's monitor. The version information begins with the characters MAIN in Screenshot 3. Note that a prompt is issued even though a Flash drive was not mounted.

ONE MORE HURDLE

Everything has worked as designed up to this point. However, we have one more test to perform before moving on to put the rest of the meat into the API. Here's the code we'll execute:

//*MAIN MAIN MAIN MAIN MAIN
void main() {
 init();
 cleaner();
 vreset();
 sync();
 sendchar(0x0D);
 do{
 ++sync_loops;
 }while(1);

■ SCREENSHOT 4. Our VDIP2 and PIC18LF2620 are playing nicely together. Now that I've found a compatible Flash drive, we can move on to complete the API coding task.

Detected P2 message was sent when I mounted the Flash drive. The No Upgrade monitor message is telling us that the upgrade file (FTRFB.FTD) was not found in the root directory of the newly mounted Flash drive. Most importantly, the D:\> prompt indicates that the Flash drive I mounted is read/write compatible with the VDIP2. Welcome to Flash Drive City!

DOWNLOAD YOUR COPY OF THE API CODE

You have witnessed what it takes to issue a command. Therefore, you won't have any problems deciphering the C source in the download package that makes up the VDIP2 API. I've written the VDIP2 API to include Disk Commands, Monitor Configuration Commands, and I/O Commands. I've also included a example file read/write application in the download package.

Using the VDIP2 API coupled with the VDIP2 hardware interface we've designed and built, you should have no problems including USB Flash drives in your Design Cycle. NV

I'll run the code without mounting a Flash drive. Once the VDIP2 indicates that it is initialized and synced (the on-board VDIP2 LEDs stop flashing and extinguish), I'll mount a Flash drive. Follow along referencing Screenshot 4 and let's see if we're ready to start reading and writing to the Flash drive.

All of the monitor messages up through No Disk in Screenshot 4 were issued immediately after power-up with no Flash drive mounted. The monitor message Device Detected P2 says that a Flash drive was detected on USB Port 2. This is good as the Device