1 Reply Latest reply on Jun 21, 2018 4:52 AM by GeonaP_26

    Port Expander with LCD



      I am trying to send data via SPI to a LCD screen using a port expander.


      Can anyone help with some guidance as to how I can do it?


      I am using Microchip's MCP23S17 expander and the way I intend to connect it is according to the scheme I uploaded.


      The chip is CY8C6347BZI-BLD53.


      Thanks in advance for any help. It is much appreciated.


      Best regards.

        • 1. Re: Port Expander with LCD

          Hello Marko,


          Please develop a low level API to present a data on the LCD bus for writing. This will involve three transfers, with a enable signal toggling and the rest of the signals being the same. Kindly refer to MCP23S17 datasheet to setup the serial parallel converter and to transfer the data. If you have any issue, kindly make use of Microchip resoures.


          Based on this API you can develop two more APIs, (1) for positioning the curser, and (2) to write characters to the LCD. You may refer to the datsheet of the HD44780 for the required waveforms.


          Best Regards,

          Geona Mary