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CFAG320240CX DISPOFF Pin Question

tm_bailey

New member
Hi there.
I'm doing some programming for the CFAG CFAG320240CX-TTI-T and I'm curious about what the DISPOFF pin actually does in the hardware, since it doesn't correspond to a pin on the Epson S1D13700 controller IC. I'm guessing it's unlikely to be related to the DISP ON/OFF command for the Epson, and that it is probably does some hardware switching. Is that right?
Also, one there's only one post about the DISPOFF pin so far and it mentions that the user had some seen some deviation from the datasheet. Should I expect this or no?
To the techs: if you just want to send me a schematic, I can figure it out.

Thanks so much!

Todd
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CF Tech

Administrator
I'll ask CF Support to look up the answer to this and replay on Monday. I do not have that information here.
 

tm_bailey

New member
Thanks!
Since the Epson datasheet specifies that "for maximum reliability" the the power to the LCD glass should be applied AFTER the controller is reset, I'm really hoping that's what that pin allows.
Looking forward to your response,

Best,

Todd
 

CF Support

Administrator
I am pursuing clarity on this with our factory engineer, and will reply back with the information as soon as I have it available. Thanks for your patience on this question, I'll get you a definitive answer shortly.
 

CF Support

Administrator
Well, I have a great abundance of good news. DISPOFF is a N/C. If JDISPOFF is closed, then the pin is connected through COFF and a 10k resistor to the DISPOFFB pin of each segment driver on the module, which allows you to turn the driver ICs off using that pin.
 

tm_bailey

New member
Great. Thanks!
I just looked at the Neotec NT7086 datasheet (the driver IC) -- this pin does in fact do what I hoped it would do. (High = active, Low = disabled WHEN JDISPOFF is connected).
BTW, it looks like that 10k is a pullup to VCC and the 10uF is a filter cap to keep noise off the DISPOFF pins, so it isn't really "through" those components...:)

Thanks again,

Todd
 
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