STM32G030 with u8g2 library problem

[sunnyguhz]

Describe the bug
Hi I have an ST7567 LCD panel that has a 4-pin SPI connection, and I use U8g2 library.

The panel works fine with Arduino(ESP8266 or STM32F103C8T6) under Hardware and Software SPI mode.

It displays okay in Software SPI mode with STM32G030.

#include <U8g2lib.h>
#include <SPI.h>

//U8G2_ST7567_OS12864_1_4W_HW_SPI u8g2(U8G2_R2,  /* cs=*/ PA4, /* dc=*/ PA6, /* reset=*/ PB1);  
U8G2_ST7567_OS12864_1_4W_SW_SPI u8g2(U8G2_R2, /* clock=*/PA1, /* data=*/ PA2, /* cs=*/ PA4, /* dc=*/ PA6, /* reset=*/ PB1); 

void setup(void) {
  u8g2.begin(); 
}

void loop(void) {
  u8g2.firstPage();
  do {
    u8g2.setFont(u8g2_font_ncenB10_tr);
    u8g2.drawStr(0,24,"Hello World!");
  } while ( u8g2.nextPage() );
  delay(1000);
}

But it it just won't show anything in hardware SPI mode.

#include <U8g2lib.h>
#include <SPI.h>

U8G2_ST7567_OS12864_1_4W_HW_SPI u8g2(U8G2_R2,  /* cs=*/ PA4, /* dc=*/ PA6, /* reset=*/ PB1);  
//U8G2_ST7567_OS12864_1_4W_SW_SPI u8g2(U8G2_R2, /* clock=*/PA1, /* data=*/ PA2, /* cs=*/ PA4, /* dc=*/ PA6, /* reset=*/ PB1); 

void setup(void) {
  u8g2.begin(); 
}

void loop(void) {
  u8g2.firstPage();
  do {
    u8g2.setFont(u8g2_font_ncenB10_tr);
    u8g2.drawStr(0,24,"Hello World!");
  } while ( u8g2.nextPage() );
  delay(1000);
}

Desktop (please complete the following information):

• OS: [ Windows10]
• Arduino IDE version: [2.2.0]
• STM32 core version: [2.6.0]
• Tools menu settings if not the default: [Debug:None, Optimize:Smallest(-Os) with LTO, USB:None, U(S)ART:Disable]
• Upload method: [SWD]

Board (please complete the following information):

• Name: [Generic G030C8Tx]
• Hardware Revision: [I don't know]

[fpistm]

By default generic G030C8 uses these pins for SPI instance:

Arduino_Core_STM32/variants/STM32G0xx/G030C(6-8)T/variant_generic.h

Lines 101 to 109 in 01e4f0c

	#ifndef PIN_SPI_MOSI
	#define PIN_SPI_MOSI PA2
	#endif
	#ifndef PIN_SPI_MISO
	#define PIN_SPI_MISO PA6
	#endif
	#ifndef PIN_SPI_SCK
	#define PIN_SPI_SCK PA1
	#endif

Do you use them?
Else you can change them using setxxx api:
https://github.com/stm32duino/Arduino_Core_STM32/wiki/API#change-default-spi-instance-pins

[sunnyguhz]

This is already the best way. Think you very much.

[sunnyguhz]

Hi, I have found the cause of this problem.
My chinese net friend tell me that MISO cannot be occupied even if MISO not need for LCD panel. And it all so can be change to another pins like PA11 or PB4.

I think it is a bug for hardware SPI mode with STM32G030. Can you do something for problem?

[fpistm]

No. As SPI works fine on G0. Don't know what is your issue but not link to the core.

[sunnyguhz]

Obviously, SPI is working with a bug on G0.

[fpistm]

Not agree with your analyze. My guess is you have pin wiring issue or conflict. Or wrong library conf.