Graphics LCD read

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Anonymous
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I am using a graphics lcd (8080 interface) in my project. After finding it difficult to interface it with the psoc5 using the graphiclcdintf_v1_6 in creator I managed to inteface it by connecting it up using gpio pins in creator. I have set up my four control pins (nCS, nRD, nWR and AO) as digital outputs and connected them physically to the lcd. I have set up the 8 data pins as digital output/ digital inputs and connected to the lcd as well. I can write to the LCD perfectly - writing text and drawing some graphics. For routines that require reading, the problems begin. I cannot read the lcd memory! I suspect that I missed something in my pin setup. When i try setting up the data pins as bidirectional pins, I fail to even write to the lcd. When I set the pins as digital input and digital output I can write to the lcd but cannot read from it. Anyone with ideas- please help.  

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Anonymous
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Liberty,

   

 

   

While using Bidirectional pins, did you use external pull-up resistors?

   

By default, the drive mode for bidirectional pins will be Open Drain Drive Low.

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Anonymous
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Yes, I used the resistive pull-up and pull down setting while using the bidirectional pins. I can perfectly read the text layer of the LCD but I cant read the graphics layer without errors. I've since realised that this has been a common problem with this type of display (sed1335/  ra8835). So my problem turns out is not a PSoC problem, after all.

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Anonymous
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Ok.

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