Use of SPI on the SDT032TFT/Solomon-Systech 1298
We are going to use a microprocessor which has a monitor-like interface for the LCD. In order to control the internal registers of the SDT032TFT/SS-1298, we intended to use the SPI interface, the 3-wire type. However, it appears that the 3-wire is not supported, in mode F.
The 4-wire mode is supported, but it requires the manipulation of the C/D_n line. That is not handled well by our microprocessor, because the SPI communications are handled with a standard SPI built-in peripheral.
So we have to interface in sort of a non-standard way. Either (a) we set the C/D_n line before the SPI byte write occurs, rather than after the eighth bit, and/or (b) we attempt to change the operating mode by manipulating the "PS" lines.
Is it possible to change the PS lines, so that I can initially talk to the SDT032TFT in SPI 3-wire (mode 01) and then change it over to generic parallel (mode F) after the internal registers get set up? When do the PS lines get looked at, during reset or all the time?
Thanks,
Frank Walker
Hi Frank,
The factory commented it is possible to initial in SPI and then switch to the RGB interface as shown in the controller data sheet, but they have no experience in initializing in SPI and changing the communication to parallel.
If you try this method could you post your findings to help out others working through this same issue?
Thanks,
Mike
I would be happy to post our test results.
Before going down that road, I need to know from the factory, are the PS lines continuously active? In other words, can I just change the mode without resetting the Solomon-Systech chip?
Frank
Hi Frank,
It is not specified in the data sheet. However, there is a high possibility that the PS lines are simple logic gate so it is active all the time. However, you need to check to see if the initialization still works after you switched mode. If you decide to reset the chip, the init. code needs to be executed again from the microcontroller end. Hope this will help.
Thanks.
