NOKIA5110 LCD Driver

The MMBasic on the CGMICROMITE2 (and thus the CGMICROKIT product) supports the ILI9341 based displays using a SPI interface. These are 2.2, 2.4 or 2.8 inch displays with a resolution of 240 by 320 pixels and a color depth of 262K/65K. The driver for the display is built in.

An alternate to this display is an NOKIA5110-based LCD. This graphic display also interfaces via SPI, but it is a small 1.6 inches with a resolution of 84 by 48 pixels.

When this driver is used all of the display orientated features of MMBasic such as drawing lines, circles, text, fonts, etc will operate on this display. As this is a monochrome display, a color of zero i.e. RGB(black) is used to turn a pixel off and any other color will turn it on.

The SPI based display controllers share the SPI interface with the MMBasic program. Sharing the SPI channel is essentially transparent to the BASIC program.

These are the connections required between the LCD display board and a CGMICROMITE2 chip or CGMICROBOARD:

Where a connection is listed as “configurable” then you get to pick the specific micocontroller (uC) pin for the purpose.

Configuring the Driver

Before the driver is loaded you need to change the I/O pins allocated to A0, RESET and CS to reflect your circuit. This is done by editing the NOKIA5110 driver code.

The I/O pin allocations are set in the call to the subroutine NOKIA5110 in the first few lines of the driver. The syntax is:

NOKIA5110 myaddr%, A0-Pin, RESET-Pin, CE-Pin, Contrast, Orientation

Where:

myaddr% is the address of the CSub (do not change this entry).

DC-Pin is the I/O pin to use for the LCD display A0 signal.

RESET-Pin is the I/O pin to use for the LCD display RESET signal.

CE-Pin is the I/O pin to use for the LCD display CS signal.

Contrast &HB8 is a typical value, any value between &HB0 and may be &HBF useful.

Orientation is the orientation of the display (1 = landscape, 2 = portrait, 3 = reverse landscape, 4 = reverse portrait).

A typical configuration for the 28-pin CGMICROMITE2 would be:

NOKIA5110 myaddr%, 2, 23, 6, 1

Note that you do not need to run the OPTION LCDPANEL command to setup this display; these configuration details are taken care of by the edits described above. Also, because the call to the NOKIA5110 driver is contained in the subroutine MM.Startup MMBasic will automatically initialize the driver every time the CGMICROMITE2 is powered up or reset.

Loading the Driver

To add the driver to MMBasic you must load the code into the CGMICROMITE2 and cycle the power. You can then test the display by entering GUI TEST LCDPANEL at the command prompt. You should see a series of circles being rapidly drawn on top of each other.

If you are happy with the operation of the driver (ie, GUI TEST LCDPANEL works as expected) you can then run the command LIBRARY SAVE at the command prompt. This will transfer the driver (and any other routines in program memory) to a part of flash memory where they will be available to MMBasic but they will not show when the LIST command is used and will not be deleted when a program is loaded or NEW is used.

Restart the CGMICROMITE2 again and, for all intents and purposes, the driver is part of MMBasic. You can load, edit, run and delete programs as per normal and the driver will remain in memory. The only way that it can be removed is with the LIBRARY DELETE command or if the CGMICROMITE2 is reset to its original default configuration.

This driver was written by Peter Mather.