29-12-2020, 08:54 PM
Hi Jeffrey
The more common type of 5V LCD can be converted to 3.3V operation see here. I have done this conversion successfully to a 5V type while I was waiting for a 3.3V coming from china.
I tried the OLED types using both SPI and I2c interfaces. Compared to the parallel interface of the LCD they were slow to write to. I didn't get into it deeply but I suspect that the OLED types that I tried are wrote to pixel by pixel. Where the LCD HD44780 types are wrote to charter by charter.
Hi Jac
Thank you.
I didn't get much time to spend on it over the last few months but I am catching up a little now over the holidays.
Baring any surprises. I have the FPGA side of things finalised. I spent sometime aligning the video from the up converter and down converter with the syncs. This one of the things that I had left till last.
The FPGA is dependent on the microcontroller for the values that define the standard that is to be produced. Without the microcontroller working the FPGA cant work.
For construction or fault finding it would be helpful if the FPGA could work independently of the microcontroller. So I have stored a set of values in an array of std_logic_vector within the FPGA. This set of values can be loaded by pulling one of the FPGA pins that has been brought out to a header low. The FPGA will then produce 625 lines with a reduced amount of visible lines. I thought it best to use a reduce number of visible lines as it makes it clear that the converter is working. A poor picture below of the output.
Got some more done with the microcontroller as well, but there is still loads to be done.
Frank
The more common type of 5V LCD can be converted to 3.3V operation see here. I have done this conversion successfully to a 5V type while I was waiting for a 3.3V coming from china.
I tried the OLED types using both SPI and I2c interfaces. Compared to the parallel interface of the LCD they were slow to write to. I didn't get into it deeply but I suspect that the OLED types that I tried are wrote to pixel by pixel. Where the LCD HD44780 types are wrote to charter by charter.
Hi Jac
Thank you.
I didn't get much time to spend on it over the last few months but I am catching up a little now over the holidays.
Baring any surprises. I have the FPGA side of things finalised. I spent sometime aligning the video from the up converter and down converter with the syncs. This one of the things that I had left till last.
The FPGA is dependent on the microcontroller for the values that define the standard that is to be produced. Without the microcontroller working the FPGA cant work.
For construction or fault finding it would be helpful if the FPGA could work independently of the microcontroller. So I have stored a set of values in an array of std_logic_vector within the FPGA. This set of values can be loaded by pulling one of the FPGA pins that has been brought out to a header low. The FPGA will then produce 625 lines with a reduced amount of visible lines. I thought it best to use a reduce number of visible lines as it makes it clear that the converter is working. A poor picture below of the output.
Got some more done with the microcontroller as well, but there is still loads to be done.
Frank
