STM32F103C8T6 - ST7789_test() not working: "flickering" black screen.

[Bruur-vr]

Hello,

I tried adding your library to a test project in STM IDE (workspace 1.17.0) but I only get a black flickering screen.
I use STM programmer & STlink V2 to download the .hex file.

Board used is and official WeAct Studio BluePill+ (known for being genuine chip), TFT LCD is 1.3inch ST7789 chinese. (When using old libraries and arduino v1.6.5 I can get it to work using same pins: so LCD works (Benchmarked: fillscreen 35Mbps & clearscreen 36Mbps))

I implemented the code by first adjusting the .ioc: clock config on 40Mhz (HCLK) as suggested (I am using dupont wires). And enabled the LSE clock, since it is also connected on the board I have.

Set the prescaler for SPI on 16 to test.

Hardware SPI pins used:
MOSI (SDA) - PA7
SCK (SCL) - PA5
Other GPIO's used as Output push pull, high speed, no Pull-up/pull-down.
(CS - PA4)
DC - PA1
RST - PA0

Then continued to adjust lcd.h file:

/* If u need CS control, comment below*/
//#define CFG_NO_CS

/* Pin connection*/
#define ST7789_RST_PORT GPIOA
#define ST7789_RST_PIN  0
#define ST7789_DC_PORT  GPIOA
#define ST7789_DC_PIN   1

#ifndef CFG_NO_CS
#define ST7789_CS_PORT  GPIOA
#define ST7789_CS_PIN   4
#endif

...

/* Choose a type you are using */
//#define USING_135X240
#define USING_240X240
//#define USING_170X320

In main.c I adjusted the User code begin 2 & User code begin while:

/* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_DMA_Init();
  MX_SPI1_Init();
  /* USER CODE BEGIN 2 */
  ST7789_Init();

  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
	  ST7789_Test();
  }
  /* USER CODE END 3 */
}

Multimeter readings (using range 20V DC):

PA7, PA5 & PA0 bounce around up until 3.1V. Other pins stay around 0V

I would appreciate knowing what i'm doing wrong.

(EDIT: trying to correctly format and clearing up what range was used for multimeter)