Interfacing Noritake VFD GU256x64-355 with BS2

jhsiii

Hi,

···· I'm new here. I just want to know if I can use my BS2 to interface with·Noritake VFD GU256x64-355. I have a BS2 BOE-rev c, and I have attached the spec sheet for the VFD. Any help or any information or link in implementing this will be highly appreciated. I have searched the forum for this particular VFD, but no mention at all.

Paul Baker

I see no reason why you couldn't use a BS2 to drive the VFD, just make sure when you write the code it adheres to the timing charts. The setup they show, would take 14 pins to drive, meaning only 2 pins left over. You could reduce this to 3 using 2 74HC595s, but implement it first using a direct drive scheme to make sure your program works before incorporating shift registers.

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·1+1=10

jhsiii

Hi Paul,

···· Thanks for your quick reply. I guess I'll have to experiment driving it directly first as you have suggested, then proceed using shift registers. Would you have any information on how to implement it using shift registers, (ie, schematics, codes)? Your further assistance will be highly appreciated.

Paul Baker

You can drive 595s using the SHIFTOUT command, then cycling the /RL pin (which updates the outputs to reflect the internal shift register). Think of using the 595s as a "time slice" representing a point in time along the timing chart, therefore if there is a minimum time >0 between the transition of two seperate signals in the timing chart these represent two time frames (slices). For instance the write operation in figure 14.1 requires a minimum of 4 time slices, in the first slice C/D is changed (all other data is held constant), second slice CS, WR and DATA are changed, third slice CS, WR and C/D are changed, and finally on the 4th slice DATA is changed. The 4th slice can actually be eliminated. When reading the timing diagram, the C/D is sampled by the VFD on the falling edge of WR and the DATA is sampled on the rising edge of WR, so both the DATA and C/D must be setup one time slice prior to thier corresponding WR transition and kept constant· one time slice past the WR transistion.

Hope this helps, I am too busy to provide schematics, but there are examples of using 595s throughout the forums. Use search.parallax.com to find some examples.

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·1+1=10

jhsiii

Hi Paul,

···· Yes, it's a lot of help. I searched the forum and I got lots of information on the 595's. Again thank you very much.