187: Monday 25th April 2011

Today I decided to get the display control simplified so it was easy to trigger events from data sent to the graphic display. In order to do this I needed a development environment. Fortunately the usb interface came with a demo program as a stand alone program, but also as source code in various programming languages. I opted for visual basic in the vb.net domain as there was a vb2008 source code version of the demo already coded. First I had to download the Microsoft dot net framework. That took a while. Then I downloaded visual basic express 2010 from Microsoft. This is free, cool. Once I had done the installations and restarted my PC, I loaded the solution file and there I could edit the source code. This was great as the vb graphic interface development is really easy. So I dragged the bottom of the form down to make it bigger, added buttons for 'Reset', 'LCD on', 'LCD off', 'All points on', and 'All points off'. I also added a 'Toggle data' button this was so I could enable the data set in the check boxes for the digital outputs. I added a timer and set this to 1 second initially and set this to bring on the analogue voltage at the full 5v, then back to 0v after the timer had expired. This was connected to the 'E' terminal on the display to enable the data on the bus. So each button would set up the digital outputs, then bring on the analogue output for a time. I could see this working just fine, so I then set the timer to 10 milli seconds. On the board you can still see a short blip when the analogue output comes on and goes off again. I am using this just like a digital signal really, but I only had 8 digital outputs and they are used for D0..D7 input of the display. This made it very easy to send commands to the display. I installed a simple mechanical button on the prototype board to supply the hard reset voltage when pushed, so I could stop the display from locking me out. I could still only control the display to bring it on and off. I am not sure why this is right now, but I suspect the display is damaged at this point in time. I am not getting the LCD voltage from its on-board DC-DC converter, so I had to supply this using my split rail supply. I get the blue background, but no white dots. I tried the volume control, power control and resistance ratio settings amongst others as well as sending the data to the ram and nothing, nada. I shall wait till pay day and order another display and hopefully that will work. I shall also try contacting the manufacturer and getting them to supply me with a start sequence for the display and some tests to try out. I have the display data sheets (see link in side bar) for the display and the chip set on the display assembly. I have tried the sequence I believe is recommended by Epson and it does not work. This is disappointing, but nothing has been simple so far, and in the typical tradition of this whole project I have typically had 2 of everything, except the Zivan charger and Zapi controller that have worked faultlessly since the day I first tried them.