SBN1661 in C #1399

Grantiscool · 2021-02-05T03:03:04Z

Grantiscool
Feb 5, 2021

Hi!

I design analogue audio products for my small business and have been working on digital control for future products. I'm fairly new to C, but a couple of weeks after switching from Great Cow BASIC, I've managed to implement most of the control code in my project.

SBN1661-based controllers seem to be ideal for reproducing a frequency response chart, and I've ordered a prototype board using an ATMega164. While the board is fabricated and shipped, I'd love to get an understanding of U8G2 (or even U8Glib, but I realise that's been discontinued).

Call me an idiot, but I've spent two days trying to figure out how to assign pins for parallel* (8080 or 6800) use of the SBN1661. I THINK I've figured this out for U8Glib (via. u8g_init8bit in u8g.h), but I can't figure it out for U8G2. The Wiki seems to explain how to assign pins for Arduino and C++, but not for C.

I realise there's a lot to learn, but the first step is getting a display working, then I can gradually figure the rest out from there. I'm happy to use the original U8Glib if you guys think it'd be better, but I appreciate that this isn't the correct forum.

Any guidance would be greatly appreciated!

Cheers,

-Grant

(*The final device may use a different protocol, but due to limitations imposed by available thru-hole AVRs and the rest of my circuit, the hardware I2C/SPI pins are unavailable, so it must be parallel for now. I can hack the board and make small changes.)

olikraus · 2021-02-05T06:35:30Z

olikraus
Feb 5, 2021
Maintainer

Part of the answers might be here: https://github.com/olikraus/u8g2/wiki/u8g2as7
In C the display init should look like this:

u8g2/sys/avr/as7/main.c

Lines 174 to 176 in 3c6460a

    
           u8g2_Setup_st7565_ea_dogm132_f( &u8g2, U8G2_R0, u8x8_byte_4wire_sw_spi, u8x8_avr_gpio_and_delay ); 
        
           u8g2_InitDisplay(&u8g2); 
        
           u8g2_SetPowerSave(&u8g2, 0);

Obviously you have to modify the setup for your display.

The setup function probably will be u8g2_Setup_sbn1661_122x32_1 or u8g2_Setup_sbn1661_122x32_f (depending on how much memory you can spent for u8g2), see https://github.com/olikraus/u8g2/wiki/u8g2setupc#sbn1661-122x32

Instead of u8x8_byte_4wire_sw_spi you need to use one of the parallel port byte functions:
https://github.com/olikraus/u8g2/wiki/Porting-to-new-MCU-platform#communication-callback-eg-u8x8_byte_hw_i2c

And finally you need to provide the gpio and delay callback. You can probably takeover the code from here (including the delay procedures):

u8g2/sys/avr/as7/main.c

Line 112 in 3c6460a

    
           uint8_t u8x8_avr_gpio_and_delay(u8x8_t *u8x8, uint8_t msg, uint8_t arg_int, void *arg_ptr)

But you need to add the pins for your parallel interface. This means you need some code, which looks similar to this:

u8g2/sys/avr/as7/main.c

Lines 131 to 136 in 3c6460a

    
           case U8X8_MSG_GPIO_SPI_DATA:        // MOSI pin: Output level in arg_int 
        
           	if(arg_int) 
        
           		DISPLAY_DATA_PORT |= (1<<DISPLAY_DATA_PIN); 
        
           	else 
        
           		DISPLAY_DATA_PORT &= ~(1<<DISPLAY_DATA_PIN); 
        
           	break;

for U8X8_MSG_GPIO_D0 to U8X8_MSG_GPIO_D7. The full template (including all the case statements) is here: https://github.com/olikraus/u8g2/wiki/Porting-to-new-MCU-platform#template-for-the-gpio-and-delay-callback

6 replies

olikraus Feb 7, 2021
Maintainer

I think the initial case is missing, but all in all it looks good.

Grantiscool Feb 7, 2021
Author

Ah, U8X8_MSG_GPIO_AND_DELAY_INIT. Thanks for pointing that out.

Grantiscool Feb 22, 2021
Author

Hi Oli,

Unfortunately I can't get the display to do anything. It doesn't appear to be a connectivity or MCU issue. Only analogue sections such as backlight and contrast controls work as expected. I'm using an ATMega 1284P @ 8 MHz (prescaler disabled in fuse).

I'm using a particular GLCD (Winstar 12232* series) which has no Enable pin, which is presumably pulled high internally. The module has the pins CE1 and CE2. I've tried both these approaches:

-Assume CS1 = CE1 and CS2 = CE2
-Assume E = CE1 and CS1 = CE2

(the latter was based on something I read here: #706 )

Please see my attached code. If I can get something simple displayed, I'll be able to learn how it all works by playing with things. Sorry in advance for any glaring stupidity! My favourite programming language is solder! lol

Thanks for any help.

-Grant

//

#include <avr/io.h>
#include <u8g2.h>
#include <util/delay.h>

#define F_CPU 1000000UL

#define DISPLAY_DATA_DIR DDRC
#define DISPLAY_DATA_PORT PORTC
#define DISPLAY_DATA_PIN0 0
#define DISPLAY_DATA_PIN1 1
#define DISPLAY_DATA_PIN2 2
#define DISPLAY_DATA_PIN3 3
#define DISPLAY_DATA_PIN4 4
#define DISPLAY_DATA_PIN5 5
#define DISPLAY_DATA_PIN6 6
#define DISPLAY_DATA_PIN7 7

#define DISPLAY_RW_DIR DDRD
#define DISPLAY_RW_PORT PORTD
#define DISPLAY_RW_PIN 0

#define DISPLAY_CS1_DIR DDRB
#define DISPLAY_CS1_PORT PORTB
#define DISPLAY_CS1_PIN 1

#define DISPLAY_CS2_DIR DDRB
#define DISPLAY_CS2_PORT PORTB
#define DISPLAY_CS2_PIN 2

#define DISPLAY_DC_DIR DDRB
#define DISPLAY_DC_PORT PORTB
#define DISPLAY_DC_PIN 5

#define DISPLAY_RESET_DIR DDRD
#define DISPLAY_RESET_PORT PORTD
#define DISPLAY_RESET_PIN 3

#define P_CPU_NS (1000000000UL / F_CPU)

u8g2_t u8g2;

uint8_t u8x8_avr_delay(u8x8_t *u8x8, uint8_t msg, uint8_t arg_int, void *arg_ptr)
{
uint8_t cycles;

switch(msg)
{
	case U8X8_MSG_DELAY_NANO:   
		break;
	case U8X8_MSG_DELAY_100NANO:

#define CALL_CYCLES 26UL
#define CALC_CYCLES 4UL
#define RETURN_CYCLES 4UL
#define CYCLES_PER_LOOP 4UL

		cycles = (100UL * arg_int) / (P_CPU_NS * CYCLES_PER_LOOP);

		if(cycles > CALL_CYCLES + RETURN_CYCLES + CALC_CYCLES) 
			break;

		__asm__ __volatile__ (
		"1: sbiw %0,1" "\n\t" // 2 cycles
		"brne 1b" : "=w" (cycles) : "0" (cycles) // 2 cycles
		);
		break;
	case U8X8_MSG_DELAY_10MICRO:    // delay arg_int * 10 micro seconds
		for(int i=0 ; i < arg_int ; i++)
			_delay_us(10);
		break;
	case U8X8_MSG_DELAY_MILLI:      // delay arg_int * 1 milli second
		for(int i=0 ; i < arg_int ; i++)
			_delay_ms(1);
		break;
	default:
		return 0;
}
return 1;

}

uint8_t u8x8_avr_gpio_and_delay(u8x8_t *u8x8, uint8_t msg, uint8_t arg_int, void *arg_ptr)
{
switch(msg)
{
case U8X8_MSG_GPIO_AND_DELAY_INIT:
DISPLAY_DATA_DIR |= 1<<DISPLAY_DATA_PIN0;
DISPLAY_DATA_DIR |= 1<<DISPLAY_DATA_PIN1;
DISPLAY_DATA_DIR |= 1<<DISPLAY_DATA_PIN2;
DISPLAY_DATA_DIR |= 1<<DISPLAY_DATA_PIN3;
DISPLAY_DATA_DIR |= 1<<DISPLAY_DATA_PIN4;
DISPLAY_DATA_DIR |= 1<<DISPLAY_DATA_PIN5;
DISPLAY_DATA_DIR |= 1<<DISPLAY_DATA_PIN6;
DISPLAY_DATA_DIR |= 1<<DISPLAY_DATA_PIN7;
DISPLAY_RW_DIR |= 1<<DISPLAY_RW_PIN;
DISPLAY_CS2_DIR |= 1<<DISPLAY_CS2_PIN;
DISPLAY_CS1_DIR |= 1<<DISPLAY_CS1_PIN;
DISPLAY_DC_DIR |= 1<<DISPLAY_DC_PIN;
DISPLAY_RESET_DIR |= 1<<DISPLAY_RESET_PIN;
break;

	case U8X8_MSG_GPIO_D0:	      
		if(arg_int)
			DISPLAY_DATA_PORT |= (1<<DISPLAY_DATA_PIN0);
		else
			DISPLAY_DATA_PORT &= ~(1<<DISPLAY_DATA_PIN0);
		break;
	case U8X8_MSG_GPIO_D1:	      
		if(arg_int)
			DISPLAY_DATA_PORT |= (1<<DISPLAY_DATA_PIN1);
		else
			DISPLAY_DATA_PORT &= ~(1<<DISPLAY_DATA_PIN1);
		break;
	case U8X8_MSG_GPIO_D2:	      
		if(arg_int)
			DISPLAY_DATA_PORT |= (1<<DISPLAY_DATA_PIN2);
		else
			DISPLAY_DATA_PORT &= ~(1<<DISPLAY_DATA_PIN2);
		break;	
	case U8X8_MSG_GPIO_D3:	      
		if(arg_int)
			DISPLAY_DATA_PORT |= (1<<DISPLAY_DATA_PIN3);
		else
			DISPLAY_DATA_PORT &= ~(1<<DISPLAY_DATA_PIN3);
		break;	
	case U8X8_MSG_GPIO_D4:	      
		if(arg_int)
			DISPLAY_DATA_PORT |= (1<<DISPLAY_DATA_PIN4);
		else
			DISPLAY_DATA_PORT &= ~(1<<DISPLAY_DATA_PIN4);
		break;	
	case U8X8_MSG_GPIO_D5:	      
		if(arg_int)
			DISPLAY_DATA_PORT |= (1<<DISPLAY_DATA_PIN5);
		else
			DISPLAY_DATA_PORT &= ~(1<<DISPLAY_DATA_PIN5);
		break;	
	case U8X8_MSG_GPIO_D6:	      
		if(arg_int)
			DISPLAY_DATA_PORT |= (1<<DISPLAY_DATA_PIN6);
		else
			DISPLAY_DATA_PORT &= ~(1<<DISPLAY_DATA_PIN6);
		break;	
	case U8X8_MSG_GPIO_D7:	      
		if(arg_int)
			DISPLAY_DATA_PORT |= (1<<DISPLAY_DATA_PIN7);
		else
			DISPLAY_DATA_PORT &= ~(1<<DISPLAY_DATA_PIN7);
		break;									
	case U8X8_MSG_GPIO_CS1:        
		if(arg_int)
			DISPLAY_CS2_PORT |= (1<<DISPLAY_CS2_PIN);
		else
			DISPLAY_CS2_PORT &= ~(1<<DISPLAY_CS2_PIN);
		break;
        
    case U8X8_MSG_GPIO_CS2:
       if(arg_int)
			DISPLAY_CS1_PORT |= (1<<DISPLAY_CS1_PIN);
		else
			DISPLAY_CS1_PORT &= ~(1<<DISPLAY_CS1_PIN); 
  break;    
        
	case U8X8_MSG_GPIO_DC:        
		if(arg_int)
			DISPLAY_DC_PORT |= (1<<DISPLAY_DC_PIN);
		else
			DISPLAY_DC_PORT &= ~(1<<DISPLAY_DC_PIN);
		break;
	case U8X8_MSG_GPIO_RESET:    
		if(arg_int)
			DISPLAY_RESET_PORT |= (1<<DISPLAY_RESET_PIN);
		else
			DISPLAY_RESET_PORT &= ~(1<<DISPLAY_RESET_PIN);
		break;
	
	default:
		if (u8x8_avr_delay(u8x8, msg, arg_int, arg_ptr))	// check for any delay msgs
			return 1;
		u8x8_SetGPIOResult(u8x8, 1);      // default return value
		break;
}
return 1;

}

int main(void)
{

u8g2_Setup_sbn1661_122x32_f(&u8g2, U8G2_R2, u8x8_byte_sed1520, u8x8_avr_gpio_and_delay);
u8g2_InitDisplay(&u8g2);
u8g2_SetPowerSave(&u8g2, 0);

/* full buffer example, setup procedure ends in _f */
u8g2_ClearBuffer(&u8g2);
u8g2_SetFont(&u8g2, u8g2_font_ncenB14_tr);
u8g2_DrawStr(&u8g2, 1, 18, "Hello");
u8g2_SendBuffer(&u8g2);
	
while(1){
 
}

}

Grantiscool Feb 24, 2021
Author

The following things made U8G2 work with the WG12232A:

Setting the RESET pin as a high output manually via. DDR* & PORT* at the very start of main.c.
Sending the Display On command manually (this seemed to be commented out in the src file? probably something I did!)
U8G2's "E" assigned to WG12232's "CE1" pin, and "CS" to "CE2".
Removed U8X8_MSG_GPIO_RESET.

Cheers for creating this pretty awesome library. I'll try not to break it!

-G

PS:- NOTE FOR FUTURE USERS: Not all WG12232* displays are created equal, with some lacking an internal clock and some having all E, CE1 and CE2 pins.

olikraus Mar 7, 2021
Maintainer

👍
I am happy to see the picture :-)

olikraus · 2021-02-05T06:43:02Z

olikraus
Feb 5, 2021
Maintainer

BTW: You could still use old u8glib, it might be better optimized for AVR systems, but it is difficult for me to provide any support for u8glib.
You probably can just use the init procedure as mentioned here:
https://github.com/olikraus/u8glib/blob/f2e0c706c9462afd488023bfc81ff2d7aa4e2938/sys/atmega/hello_world/hello_world.c#L54-L55

u8glib includes a lot of support for AVR which was removed for u8g2 to make u8g2 more portable. So the advantage of u8glib would be, that you do not need to write a callback function for the IO and delay procedures.

1 reply

Grantiscool Feb 5, 2021
Author

Hi Oli,
Thanks SO much for taking the time. I'll have a good read and try to understand it all tonight (when my toddler stops kicking me in the brain!).

-Grant

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SBN1661 in C #1399

Grantiscool Feb 5, 2021

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