CFAG12864B data sheet clarifications


New member
I am currently interfacing a CFAG12864B-TMI-V display to an Atmel AVR processor and have been working with the data sheets and have a few questions which I need resolved:

1. The Interface Description for the display lists the reset signal (RST) level as Low - does this mean that to initialize the display I could take this pin high and then back low and then leave it low?
Is there any timing necessary?

2. The Interface Description also lists the R/W pin as being high for a read and low for a write which makes sense. However the chart under the Timing Characteristics section appears to be the reverse. The MPU Timing diagram appears to show taking the R/W signal high during the write cycle. Can you clarify this and let me know what is correct?

3. Once that's all taken care of, if I understand correctly, the write cycle should look something like this:

- take enable line low
- set R/W line low
- set D/I line high for data and low for instruction
- set either cs1 or cs2 low if data
- set enable high
- put data on data bus
- take enable line low

This sequence should then write the appropriate command or data to the display. Is that correct or am I missing something?

I hope this all makes sense, thanks for the help

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New member

You obviously seem not to be aware of the fact that, in datasheet language, when they say a signal level is, for example, LOW, they mean ACTIVE LOW.
Which means, when the signal is ACTIVE, you must take it to the mentioned state.
Specifically, the RESET signal has to remain HIGH, unless you want the circuit to reset, in which case, you take it LOW and back HIGH again, and it remains HIGH for the rest of the operation.
The same applies with the rest of the signals, which is, probably, why the signals appear to you reverse in the timing chart.
Besides, the R/W signal is, in fact R/!W (read READ/NOT WRITE) which means, when the signal is LOW (ie logical 0) it's 0 for READ and 1 for WRITE, while when the signal is HIGH (ie logical 1) it's 1 for READ and 0 for WRITE. You can understand from that, what happens when.


New member
need code sample and pins info

I am looking for some code for the CFAG12864B-WGHN. Also
I was not able to find the pins descriptions for this display.
Thank you much for any code and /or pins info.