NHD-0420CW on XMEGA

[LoyalServant]

So I was able to get this display going using an atmega and now I am giving an XMEGA a whirl.
Few things changed here, most notably that it's on a 3.3v supply now instead of 5v.

I am thinking initialization problem?


code that is not working:

Code: [Select]

#define F_CPU 32000000UL

#include <avr/io.h>
#include <util/delay.h>

const uint8_t ROW_N = 4;               // Number of display rows
const uint8_t COLUMN_N = 20;           // Number of display columns
const uint8_t SLAVE = 0x3C;            // Display I2C address, in 7-bit form: 0x3C if SA0=LOW, 0x3D if SA0=HIGH
uint8_t new_line[4] = {0x80, 0xA0, 0xC0, 0xE0};               // DDRAM address for each line of the display
uint8_t rows = 0x08;                     // Display mode: 1/3 lines or 2/4 lines; default 2/4 (0x08)
uint8_t tx_packet[] = {0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00}; // Packet to be transmitted (max 20 bytes)

#define BAUDRATE    100000L
#define TWI_BAUD(F_SYS, F_TWI) ((F_SYS / (2 * F_TWI)) - 5)
#define TWI_BAUDSETTING TWI_BAUD(F_CPU, BAUDRATE)


void twi_write(uint8_t writeData)
{

uint8_t addr = 0;
addr |= SLAVE << 1;

TWIC.MASTER.ADDR = addr;
while(!(TWIC.MASTER.STATUS & TWI_MASTER_WIF_bm));

TWIC.MASTER.DATA = writeData;
while(!(TWIC.MASTER.STATUS & TWI_MASTER_WIF_bm));
TWIC.MASTER.CTRLC = 0x03; // ???

return;
}

void twi_init()
{
TWIC.CTRL = 0x00;
TWIC.MASTER.CTRLB = TWI_MASTER_SMEN_bm;
TWIC.MASTER.BAUD = TWI_BAUDSETTING;
TWIC.MASTER.CTRLA = TWI_MASTER_ENABLE_bm;
TWIC.MASTER.STATUS = TWI_MASTER_BUSSTATE_IDLE_gc;
return;
}

void send_packet(uint8_t x)
{
uint8_t ix = 0;

for(ix=0; ix<x; ix++)
{
twi_write(tx_packet[ix]);
}
}

void command(uint8_t c)
{
tx_packet[0] = 0x00;
tx_packet[1] = c;
send_packet(2);
}

void data(uint8_t d)
{
tx_packet[0] = 0x40;
tx_packet[1] = d;
send_packet(2);
}

void initlcd(void)
{

if (ROW_N == 2 || ROW_N == 4)
{
rows = 0x08;                    // Display mode: 2/4 lines
}
else
{
rows = 0x00;                    // Display mode: 1/3 lines
}

command(0x22 | rows); // Function set: extended command set (RE=1), lines #
command(0x71);        // Function selection A:

data(0x00);   // 3.3v ??????
//data(0x5C);           //  enable internal Vdd regulator at 5V I/O mode (def. value) (0x00 for disable, 2.8V I/O)

command(0x20 | rows); // Function set: fundamental command set (RE=0) (exit from extended command set), lines #
command(0x08);        // Display ON/OFF control: display off, cursor off, blink off (default values)
command(0x22 | rows); // Function set: extended command set (RE=1), lines #
command(0x79);        // OLED characterization: OLED command set enabled (SD=1)
command(0xD5);        // Set display clock divide ratio/oscillator frequency:
command(0x70);        //  divide ratio=1, frequency=7 (default values)
command(0x78);        // OLED characterization: OLED command set disabled (SD=0) (exit from OLED command set)

if (ROW_N > 2)
{
command(0x09);  // Extended function set (RE=1): 5-dot font, B/W inverting disabled (def. val.), 3/4 lines
}
else
{
command(0x08);  // Extended function set (RE=1): 5-dot font, B/W inverting disabled (def. val.), 1/2 lines
}

command(0x06);        // Entry Mode set - COM/SEG direction: COM0->COM31, SEG99->SEG0 (BDC=1, BDS=0)
command(0x72);        // Function selection B:
data(0x0A);           //  ROM/CGRAM selection: ROM C, CGROM=250, CGRAM=6 (ROM=10, OPR=10)
command(0x79);        // OLED characterization: OLED command set enabled (SD=1)
command(0xDA);        // Set SEG pins hardware configuration:
command(0x10);        //  alternative odd/even SEG pin, disable SEG left/right remap (default values)
command(0xDC);        // Function selection C:
command(0x00);        //  internal VSL, GPIO input disable
command(0x81);        // Set contrast control:
command(0x7F);        //  contrast=127 (default value)
command(0xD9);        // Set phase length:
command(0xF1);        //  phase2=15, phase1=1 (default: 0x78)
command(0xDB);        // Set VCOMH deselect level:
command(0x40);        //  VCOMH deselect level=1 x Vcc (default: 0x20=0,77 x Vcc)
command(0x78);        // OLED characterization: OLED command set disabled (SD=0) (exit from OLED command set)
command(0x20 | rows); // Function set: fundamental command set (RE=0) (exit from extended command set), lines #
command(0x01);        // Clear display
_delay_ms(2);             // After a clear display, a minimum pause of 1-2 ms is required
command(0x80);        // Set DDRAM address 0x00 in address counter (cursor home) (default value)
command(0x0C);        // Display ON/OFF control: display ON, cursor off, blink off
_delay_ms(250);           // Waits 250 ms for stabilization purpose after display on

if (ROW_N == 2)
{
new_line[1] = 0xC0;             // DDRAM address for each line of the display (only for 2-line mode)
}
}

void blocks(void)
{
uint8_t r = 0;
uint8_t c = 0;

command(0x01);                     // Clear display (and cursor home)
_delay_ms(2);

for (r=0; r < ROW_N; r++)
{
command(new_line[r]);
for (c=0; c < COLUMN_N; c++)
{
data(0xDB);                  //  displays character 0xDB (block)
_delay_ms(100);
}
}
}

int main(void)
{

CCP = 0xD8;
OSC.CTRL = 0x02;
while(!(OSC.STATUS & 0x02));
CCP = 0xD8;
CLK.CTRL = 0x01;

twi_init();
initlcd();

uint8_t addr = 0;
addr |= SLAVE << 1;

    /* Replace with your application code */
    while (1)
    {
//TWIC_MASTER_ADDR = addr;
blocks();
    }
}



[LoyalServant]

I got this going... was sending data wrong.....
Senior moment again.

[Paul_B]

Glad to hear you got your display up and running! 

[LoyalServant]

Glad to hear you got your display up and running! 

Thank you Paul.

Question: What bus speeds are supported in I2C mode?

I plugged this example into it's main project where I have devices running in Fm and Fm+ and everybody is happy but this display is running at standard 100Khz.
I bumped it to >100Khz and it seemed to work fine.
What's the word on bus speeds?

[Paul_B]

Up to 400kbit/s