Porting SSD1306 for Oled

[Takatoshi Nao]

I need to port ssd1306 library for oled to nrf51822.

so i tested following code. but it's not worked.

main(){
    if (!twi_master_init())
    {
        return false;
     }
     ssd1306_init();
}
static bool ssd1306_lcd_set_instruction(uint8_t instr)
{
    nrf_delay_us(10000);
    data_buffer[0] = 0x00;
    data_buffer[1] = instr;
    return twi_master_transfer(SSD1306_SA << 1, data_buffer, 2, TWI_ISSUE_STOP);
}
bool ssd1306_init(void)
{
if (!ssd1306_lcd_set_instruction(0xAE)) <- not worked , returns false
    return false;
	if (!ssd1306_lcd_set_instruction(0x00)) 
    return false;
	if (!ssd1306_lcd_set_instruction(0x10)) 
    return false;
	if (!ssd1306_lcd_set_instruction(0x40))
    return false;
	if (!ssd1306_lcd_set_instruction(0x81)) 
    return false;
	if (!ssd1306_lcd_set_instruction(0xCF)) 
    return false;
	if (!ssd1306_lcd_set_instruction(0xA1)) 
    return false;
	if (!ssd1306_lcd_set_instruction(0xC8))
    return false;
	if (!ssd1306_lcd_set_instruction(0xA6))
    return false;
	if (!ssd1306_lcd_set_instruction(0xA8)) 
    return false;
	if (!ssd1306_lcd_set_instruction(0x3F)) 
    return false;
	if (!ssd1306_lcd_set_instruction(0xD3)) 
    return false;
	if (!ssd1306_lcd_set_instruction(0x00)) 
    return false;
	if (!ssd1306_lcd_set_instruction(0xD5)) 
    return false;
	if (!ssd1306_lcd_set_instruction(0x80)) 
    return false;
	if (!ssd1306_lcd_set_instruction(0xD9)) 
    return false;
	if (!ssd1306_lcd_set_instruction(0xF1)) 
    return false;
	if (!ssd1306_lcd_set_instruction(0xDA)) 
    return false;
	if (!ssd1306_lcd_set_instruction(0x12)) 
    return false;
	if (!ssd1306_lcd_set_instruction(0xDB)) 
    return false;
	if (!ssd1306_lcd_set_instruction(0x40)) 
    return false;
	if (!ssd1306_lcd_set_instruction(0x20)) 
    return false;
	if (!ssd1306_lcd_set_instruction(0x02)) 
    return false;
	if (!ssd1306_lcd_set_instruction(0x8D))
    return false;
	if (!ssd1306_lcd_set_instruction(0x14)) 
    return false;
	if (!ssd1306_lcd_set_instruction(0xA4)) 
    return false;
	if (!ssd1306_lcd_set_instruction(0xA6)) 
    return false;

return ssd1306_lcd_set_instruction(0xAF);               
}

Another question. How can I draw screen? Thank you all..

void ssd1306_fillscreen(uint8_t fill_Data)
 {
uint8_t m,n;
for(m=0;m<8;m++)
{
	ssd1306_lcd_set_instruction(0xb0+m);	//page0-page1
	ssd1306_lcd_set_instruction(0x00);		//low column start address
	ssd1306_lcd_set_instruction(0x10);		//high column start address
	
	nrf_delay_us(1000);
	data_buffer[0] = DATA_SET; // 0x40
	twi_master_transfer(SSD1306_SA << 1, data_buffer, 1, TWI_DONT_ISSUE_STOP);
	for(n=0;n<127;n++)
	{
		data_buffer[0] = fill_Data;
		twi_master_transfer(SSD1306_SA << 1, data_buffer, 1, TWI_DONT_ISSUE_STOP);
		//ssd1306_send_byte(fill_Data);
	}
	data_buffer[0] = fill_Data;
	twi_master_transfer(SSD1306_SA << 1, data_buffer, 1, TWI_ISSUE_STOP);
	
	//ssd1306_send_data_stop();
}
 }

[Nenik]

What is your SSD1306_SA? 0x3C? I use very similar code and SSD1306 based display and it works well for me, but I use 0x78 directly (the shift might have been already factored in the datasheet, IIRC)

[Takatoshi Nao]

hello nenik, SSD1306_SA is 0x78. but it's not worked. can you advice to me? Do I have to use 0x3C???!!

[Stian Røed Hafskjold]

In this function:

return twi_master_transfer(SSD1306_SA << 1, data_buffer, 2, TWI_ISSUE_STOP);

you are shifting the address 1 bit left. In the SSD1306 documentation, the address should be in this form:

0 1 1 1 1 0 SA0 R/W

Which is 0x3C shifted one bit left. (As long as SA0 and R/W is 0)

You can set SSD1306_SA to be 0x3C, or write 0x78 directly like this, as Nenik suggests:

return twi_master_transfer(0x78, data_buffer, 2, TWI_ISSUE_STOP);

[Clem Taylor]

If your hardware isn't fixed yet, save yourself some pain and use the SSD1306 based display with SPI not I2C. The SPI interface is so much faster and requires much less CPU time to feed.

I'm using a SSD1306 based display with the SPI interface and I've been very happy with it (except for what seems to be a chip bug in the handling of writes to the start line register).

[Takatoshi Nao]

Thank Clem.