README.md
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. Matrix Display Controller

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The MDC (Matrix Display Controller) is to interact with a dot matrix display (like the ]]>Kingbright TA20]]>) over SPI bus or UART (See the command list below).

Board




  
Download
  
Description




  
Schematic
  
Complete Schematic of the Display


  
KiCAD
  
KiCAD files


  
Gerber
  
Gerber production and drill files




3D Model




  
TOP
  
BOT




  

  





Agenda




  
Board
  
Status




  
Schematic
  
✔️ Done


  
Board
  
✔️ Done


  
Partlist
  
✔️ Done


  
Production
  
✔️ Done


  
Assembly
  
✔️ Done


  
Case
  
❌ Open




Firmware ]]>]]>




  
Image
  
Download




  
Display
  
]]>zip]]> / ]]>tar.gz]]>


  
Demo (ATmega16)
  
]]>zip]]> / ]]>tar.gz]]>




Display

The display can be driven in two modes either the standard (spi) mode or the uart mode.

SPI mode

The display can be controlled with the matrix library. The library can be found in the TEST project. The library is modular and can be adapted onto other plattforms. For platform adaptions the spi library has to be rewritten for the target platform. Currently the library can be used with an ATmega16A.

Startup

// User libraries


include "matrix/matrix.h"

// ...
int main(void)
{
    matrixinit();
    _delayms(1000);
    matrixclearall();
    delayms(1000);
}


Standard commands




  
Command
  
Description




  
matrix_init()
  
Initializes the display


  
matrix_buffer(0-255, ARRAY)
  
Send an array (5*7) bits to a specific display


  
matrix_buffer_all(ARRAY)
  
Send an array (5*7) bits to all displays


  
matrix_char(0-255, ASCII)
  
Send an ASCII char to a specific display


  
matrix_string(STRING)
  
Send an ASCII string to a all display


  
matrix_clear(0-255)
  
Clear a specific display


  
matrix_clear_all()
  
Clear all displays




Speical commands




  
Define
  
VALUE
  
Description




  
MATRIX_EEPROM_CHAR0
  
0x00
  
EEPROM address of MEMORY 0


  
MATRIX_EEPROM_CHAR0
  
0x01
  
EEPROM address of MEMORY 1


  
...
  
...
  
...


  
MATRIX_EEPROM_CHAR0
  
0x0E
  
EEPROM address of MEMORY E


  
MATRIX_EEPROM_CHAR0
  
0x0F
  
EEPROM address of MEMORY F







  
Command
  
Description




  
matrix_prom_write(0-255, DEFINE, ARRAY)
  
Save an array (5*7) to the display EEPROM


  
matrix_prom_read(0-255, DEFINE)
  
Load an array from EEPROM to the display




Example

// TEST Connection
//
//          uC                 DISPLAY 0              DISPLAY 1
//  ~~~~~~~~~~~~~~~~~+    +~~~~~~~~~~~~~~~~~+    +~~~~~~~~~~~~~~~~~+
//    A  (M)         |    |                 |    |                 |
//    T  (E)     VCC +----+ VCC         VCC +----+ VCC         VCC |
//    M  (G)         |    |                 |    |                 |
//    E  (A)    MOSI +----+ MOSI       MISO +----+ MOSI       MISO |
//    G  (C)     SCK +----+ SCK         SCK +----+ SCK         SCK |
//    A  (A)      SS +----+ SS           SS +----+ SS           SS |
//    1  (R)     GND +----+ GND         GND +----+ GND         GND |
//    6  (D)         |    |                 |    |                 |
//    A              |    +~~~~~~~~~~~~~~~~~+    +~~~~~~~~~~~~~~~~~+
//  ~~~~~~~~~~~~~~~~~+


define F_CPU 12000000UL    // System clock (required for delay)

// System libraries

include <avr/io.h>

include <util/delay.h>

// User libraries

include "matrix/matrix.h"

// ...
int main(void)
{
    matrixinit();
    _delayms(1000);
    matrixclearall();
    delayms(1000);

unsigned char buffer[] = {
    0b01000,
    0b01000,
    0b01000,
    0b01000,
    0b01000,
    0b01000,
    0b11111
}; 

// Send buffer to display 0
matrix_buffer(0, buffer);
_delay_ms(1000);

// Send buffer to all displays
matrix_buffer_all(buffer);
_delay_ms(1000);

// Send ASCII char to display 0
matrix_char(0, 'A');
_delay_ms(1000);

// Send string to displays
matrix_string(0, "TEST");
_delay_ms(1000);

// Clear display 0
matrix_clear(0);
_delay_ms(1000);

// Clear all displays
matrix_clear_all();
_delay_ms(1000);

// !!! Only one time necessary !!!
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// !!! Warning:                                    !!!
// !!! Don´t call this function in a while(1) loop !!!
// !!! This will damage the EEPROM                 !!!
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

// Save buffer in display EEPROM
matrix_prom_write(0, MATRIX_EEPROM_CHAR0, buffer);
_delay_ms(1000);

// Read data from EEPROM
matrix_prom_read(0, MATRIX_EEPROM_CHAR0);
_delay_ms(1000);


}


UART mode

The standard ASCII characters can also be transferred to display over UART. Therefore a special configuration is necessary. Pin SS should be connected to ground (GND) before powering the display.

// TEST Connection
//
//           DISPLAY 0              USB/UART
//      +~~~~~~~~~~~~~~~~~+   +~~~~~~~~~~~~~~~~~+
//      |                 |   |                 |
//      + VCC         VCC +---+ VCC             |
//      |                 |   |             +---+
//      + MOSI       MISO +---+ TXD         | U |
//      + SCK         SCK +   |             | S |
//  +---+ SS           SS +   |             | B |
//  +---+ GND         GND +---+ GND         +---+
//      |                 |   |                 |
//      +~~~~~~~~~~~~~~~~~+   +~~~~~~~~~~~~~~~~~+


Characters can be sent to the display over ]]>TeraTerm]]> or ]]>Putty]]>
UART should contain following setup:




  
Parameter
  
Value




  
Baudrate
  
9600


  
Datasize
  
8 Bit


  
Parity
  
None


  
Stopbits
  
1