i80 Bus Timing Discrepancy
Hello all,
I see a discrepancy in the documentation regarding the timing of the i80 bus transactions.
Figure 24 shows example reads and writes using the i80 bus in 8-bit mode. It clearly shows that nCS is active _before_ the RS bit is set. In fact, this is required because the RS bit is active for some parts of the transaction and not for others.
But Figure 48 shows that the RS bit needs to be stable before nCS is active.
So I'm not sure which is right but I'm violating one of them and perhaps that is a cause of grief ???
For reference, I am using version 0.30 of the ILI9326 datasheet.
Cheers,
James.
Jim, I have noticed this discrepancy also. I emailed support at ILI and have not got a response from them. This was about 2 weeks ago. I tried a little experiment and moved the control line sequence around and I could not get it to operate right. I just received a new display today and hooked it up. It works the same as the old display so I know that it is not the display.
I also just noticed that the initialization process does not always work right on powerup. After a few attempts at the initialization the display will usually allow you to write to the pixels. This is telling me that there is some type of timing issue, or sequence issue. If I find out anything more I will let you know.
I have my display hooked up to discrete pins on the pic, so I can change sequences pretty easily. I am not using the pmp module.
Stephan.
Hi,
I can not get a good initialization after power up no matter what I try. There must be some thing wrong with the initialization sequence supplied. Once the display starts displaying pixels, I can not place a pixel on the display.
Since the documentation contains two timing diagrams that are opposite figure 24 and figure 48, would it be possible for the factory to supply a timing diagrams and code examples that work to drive this display? The examples should show how to write a horizontal line, and a vertical line. The routines should show every state change for every control line, and include any timing gotchas.
Thanks,
Stephan.
Jim,
I got a reply from ilitek, They submitted the following timing diagram.
They also sent me a new version of the data sheet, version 0.30, the version that is saved on the display-tech website is version 0.24. I am going to verify that this is what I have right now. The current initialization that I have will give me the full display with very washed out colors once or twice, then it will give me about the right 1/3 of the display with bright colors, until the display is powered down again and it will repeat this if it works at all. I have verified that the reset line is driven, and I hold it low for 200 mS, then drive it high and delay for 200 mS before I try to write to any of the registers.
Attachment: ILI9326DS_V030.pdf (1390.0KB)
