6 years, 10 months ago.


Hi, i've a HY28A-LCDA, w/Parallel Interface, Do you know how make this work???


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2 Answers

6 years, 8 months ago.

Did you get it going...I had problems as well. You need to add in code to reset the chip via an external line, also you need to set the CS line high initially in the chip reset method. I also found problems in the font section, If you are using a large font or a more rectangular font the width and height are mixed up when calculating the window size. I also added in code to allow for big fonts where the data in a line of the font exceeds 256. Mark

6 years, 8 months ago.

The HY28A has both a LCDA 16-bit parallel i/f and a LCDB SPI i/f.

LCDA requires 19 GPIO pins + RESET. LCDB requires 4 GPIO pins.+ RESET.

Whereas the parallel i/f is faster, most MBED platforms don't have enough spare pins. You also don't have a straight port correspondence. e.g. P0_0 .. P0_15.

So if you are trying to connect a FRDM25Z or MBED-1768 board, you need to map pins all over the place. e.g. lots of shifts and masks.

In contrast, you can use the hardware SPI or SSP pins and run the SPI at full speed.

I have only driven the HY28A via SPI on the MBED, FRDM25Z and LPC-MAX hardware - but not by the MBED compiler. Just regular C or C++.

I suppose that I can try building via MBED Compiler one day.