Second SPI not working for LCD ST7920 or SPI Flash W25Q128 using with STM32F103C8T6 (Blue Pill) or STM32F401CCU (Black Pill)

[delgadosouza]

Describe the bug
I tried using the LCD ST7920 or the SPI Flash W25Q128 (only one at a time) but I was not able to use any of them on the second SPI port of any of the variants BluePill and BlackPill.

To Reproduce

For the LCD 7920
I am using the u8g2 library that have the constructor for using what should be the second SPI.

#include "U8g2lib.h" // by olikraus

#define LCDROTATION U8G2_R0
#define SCK_E_CLOCK PB13
#define MOSI_RW_DATA PB15
#define SS_RS_CS PB12
#define RST_RESET PA3

U8G2_ST7920_128X64_F_2ND_HW_SPI disp(LCDROTATION, SS_RS_CS, RST_RESET);
// THE LINE BELOW WORKS, but slow: software SPI.
//U8G2_ST7920_128X64_F_SW_SPI disp(LCDROTATION, SCK_E_CLOCK, MOSI_RW_DATA, SS_RS_CS, RST_RESET);

int ypos = 22;

void setup(){
  disp.begin();
  delay(100);
  disp.setBusClock(1000000); // If higher gives artifacts on the screen over time
  delay(100);
}

void loop(){
  // Show something
  disp.clearBuffer();
  disp.setFontMode(1);
  disp.setDrawColor(1);
  disp.setFont(u8g2_font_pcsenior_8u);
  disp.drawStr(22,ypos,"HELLO WORLD");
  disp.sendBuffer();
  delay(50);
  ypos++;
  if(ypos>50){
    ypos=22;
  }
}

It compiles but nothing is shown on screen. Tested with Arduino IDE 1.8.13 and also Arduino IDE 1.9.0-beta for both STM32F103C8T6 and STM32F401CCU.
In an issue for that library the author mentions that the core should be setting the flag SPI_INTERFACES_COUNT, following Arduino API. It was not being defined so I tried defining SPI_INTERFACES_COUNT 2 on the beggining of the U8x8lib.h file and got the error:

\src\U8x8lib.cpp:1000:7: error: request for member 'transfer' in '(SPI_TypeDef*)((1073741824 + 65536) + 12288)', which is of pointer type 'SPI_TypeDef*' (maybe you meant to use '->' ?)

So I openned the U8x8lib.cpp file and tried to hardcode the constructor for the second SPI
SPIClass mySPI_2(uint8_t mosi, uint8_t miso, uint8_t sclk, uint8_t ssel)
and exchanged all occurrences of SPI1 by mySPI_2 and it compiled but the screen was blank.

For the SPI Flash Winbond W25Q128
To make sure the frequency wasn't too high I changed the "defines.h" file of the library SPIMemory. I edited the frequency for non ESP32 boards:

#if defined (ARDUINO_ARCH_ESP32)
#define SPI_CLK       20000000        //Hz equivalent of 20MHz
#else
#define SPI_CLK       1000000       //Was 104000000
#endif

Also I had to define the ARCH_STM32 flag that was used by the library but not set by the core.

#define ARCH_STM32 true // The library didn't recognize the archtecture by itself
#include<SPIMemory.h> // SPIMemory library v 3.2.0 by Marzogh

// SPI2
#define SPI2_MISO PB14
#define SPI2_MOSI PB15
#define SPI2_SCK PB13
#define SPI2_CS PB12

// SPI 1
#define SPI1_SCK PA5
#define SPI1_MOSI PA7
#define SPI1_MISO PA6
#define SPI1_CS PA4

// THE LINES BELOW WORK (wired to SPI1 instead of SPI2, of course)
//SPIClass my_SPI1(SPI1_MOSI,SPI1_MISO,SPI1_SCK,SPI1_CS);
//SPIFlash flash(SPI1_CS, &my_SPI1);

SPIClass my_SPI2(SPI2_MOSI,SPI2_MISO,SPI2_SCK,SPI2_CS);
SPIFlash flash(SPI2_CS, &my_SPI2);

void setup() {
  Serial.begin(115200);
  while (!Serial) ; // Wait for Serial monitor to open
  delay(50);
  
  flash.begin();
  delay(50);

  // Get ID
  uint32_t JEDEC = flash.getJEDECID();
  if (!JEDEC) {
    Serial.println("Check wiring.");
  } else {
    // Show ID
    Serial.print("JEDEC ID: 0x"); Serial.println(JEDEC, HEX);
    Serial.print("Man ID: 0x"); Serial.println(uint8_t(JEDEC >> 16), HEX);
    Serial.print("Memory ID: 0x"); Serial.println(uint8_t(JEDEC >> 8), HEX);
    Serial.print("Capacity: "); Serial.println(flash.getCapacity());
    Serial.print("Max Pages: "); Serial.println(flash.getMaxPage());
  }
}

void loop() {}

Answer on SPI 1:

Answer on SPI 2:

For some reason it didn't even print the "Check wiring." message...

Desktop (please complete the following information):

• OS: Windows 10 Pro Version 1909
• Arduino IDE version: Tested with Arduino IDE 1.8.13 Hourly Build and also Arduino IDE 1.9.0-beta.
• STM32 core version: STM32 Cores 1.9.0
• Tools menu settings if not the default:
  For Blue Pill:
  

For Black Pill:

Tried same cofigs on both Arduino IDE versions.

• Upload method: STLink for the BluePill and USB (DFU) for BlackPill

Board (please complete the following information):

• Name: Blue Pill STM32F103C8T6 and Black Pill STM32F401CCU
• Hardware Revision: WeAct v2.0 (Black Pill), Generic BluePill
• Extra hardware used if any: Blue LCD 128x64 ST7920 and SPI Flash W25Q128
  
  

Additional context
I would like to use both the LCD ST7920 and the SPI Flash W25Q128, each one in a separate SPI. I have heard that the ST7920 controller doesn't play nicely with other devices on the same bus.

I also want to just comment that the boot sequence hold BOOT + press NRST + release BOOT not always work for the STM32F401UCC. Nearly 90% of the time Windows doesn't recognize the device after this sequence. Eventually it is recognized as STM32 BOOTLOADER and then everything goes fine. Also on Arduino IDE 1.8.12, after uploading any sketch the BlackPill freezed, not even a blink would work. I've read about some issue with clock and you probably have solved it already so it is just a comment.

I hope you can help me and thank you for the possibility of using arduino on these boards!

[fpistm]

Hi @delgadosouza
unfortunately, it seems linked to the third party library and how it allows to manage the SPI instance.
There is a request to support the interface count, see #705
Probably it could help for this library usage.

You can try to use the second SPI without third party library, I know it works.
So I could not help on this as it is a third party library issue and if the only way is to use interface count then you will have to wait someone do a PR for #705

[delgadosouza]

I see, I will read the thread, thank you!