SPI mode for module HD44780

[espruino-discuss2]

Posted at 2017-11-22 by @yerpj

Hi guys,

I am planning to interface my Pico with a 20x4 character OLED display OLED-020N004B from Vishay (info here: https://www.vishay.com/displays/list/product-37706/). It seems to behave like a HD44780-like display: the built-in controller is a "OLED-0010", doc here: http://docs-europe.electrocomponents.com/webdocs/1401/0900766b814011cc.pdf

This controller has the ability to interract with 6800, 8080 and SPI interface. SPI seems to be mapped on DB7(MOSI), DB6(MISO), DB5(SCK) and E(CS).
I had a look at the HD44780 module (http://www.espruino.com/modules/HD44780.js); it does not seem to support SPI mode right now.

Does anyone have any idea of how I could add a .connectSPI method on this module?

[gfwilliams]

Posted at 2017-11-22 by @gfwilliams

Hi!

You should be able to do:

var HD44780 = require("HD44780").HD44780;

connectSPI = function(spi, cs) {
  return new HD44780(function(x, c) {
    // ...
  });
};

That'll work even without touching the module - but if you get something working it'd be great if you could contribute your code so I can stick it in the main one :)

[espruino-discuss2]

Posted at 2017-11-22 by @allObjects

@gordon, did you just change the module per this occasion? ...because when I look at it I see:

...straight out of the 'Header' of modules/HD44780.js:

////////////////////////////
.....
...

If you have one of the LCDs with an I2C backpack, just use:

I2C1.setup({scl:B6, sda:B7});
var lcd = require("HD44780").connectI2C(I2C1);
lcd.print("Hello World!");

You can specify device address following way:

require("HD44780").connectI2C(I2C1, 0x3F);

Otherwise try:

var lcd = require("HD44780").connect(A4,A5,A0,A1,A2,A3);
lcd.print("Hello World!");

...
.....
////////////////////////////

The implementation is:

exports.connectI2C = function(/*=I2C*/i2c, _addr) {
  return new HD44780(function(x, c) {
    var a = (x&0xF0) |8| ((c===undefined)?1:0);
    var b = ((x<<4)&0xF0) |8| ((c===undefined)?1:0);
    i2c.writeTo(_addr || 0x27, [a,a,a|4,a|4,a,a,b,b,b|4,b|4,b,b]);
  });
};

So there is a plain .connect(... and a .connectI2C(....

[gfwilliams]

Posted at 2017-11-22 by @gfwilliams

... and right at the bottom there's exports.HD44780 = HD44780; - so you can access the HD44780 class directly :) I think this came up before when someone was looking at driving the display via a different kind of IO expander, and it got added there.