Vinculum Vdrive2

[botsmaker]

I have built a logger using the Vdrive2 and wrote a blog on it. At the blog I posted schematics and code for both a 8 bit and 10 bit version. The logger uses a DS1307 for a time stamp and saves data at 1 per second using a 16F688 pic and Pic Pro Basic.

[RussMartin]

The VMusic2 is also cute.

[Bill Legge]

For Bill/mark Sherman at BOTSMAKER

Thanks for taking the trouble to put your VDRIVE2 project on the web.

I'm just starting with my VDRIVE2 and have been trawling through your PIC Basic Pro code to learn how to do it.

I'm not clear why your 'write' command works? According to the FTDI notes the command is:

"WRF", $hhhh

Where $hhhh is a word that is the number of BYTES following that are to be written to the currently open file.

Your format seems to be:

"WRF",$00,$00,$00,$15,$0d,DEC yy10.........

Why does this work please?

Regards Bill Legge

[botsmaker]

Whats wrong with it? $00 $00 $00 $15 = 21 in decimal. This tells the vinculum that 21 bytes will follow to be written. If you add up the bytes, you get 21.

[Bill Legge]

Thanks for your reply.

I thought the VDrive2 would take the first four hex numbers after the "WRF" and read zero bytes to follow?

What are the $00 doing?

Regards Bill legge

[botsmaker]

WRF is reading a long word of 32 bits, starting with MSB first. So if the first 3 bytes are zero, you must read in a zero. You can't take a short cut and just send $15.

[Bill Legge]

Thanks,

I'd not seen that the VDrive2 was looking for a LONG.

Regards Bill Legge