Use of STM32F103C8T6 + ILI9341 + Adafruit_GFX

I need to know the correct connections STM32 <=>ILI9341 TFT screen using the Adafruit_GFX library:
The library doesn’t say which TM32F103C8T6 pins are used.

// Start of my sketch
#include <Adafruit_ILI9341_8bit_STM.h>
#include <SPI.h>
#include <Adafruit_GFX.h>
#include <gfxfont.h>

Adafruit_ILI9341_8bit_STM tft = Adafruit_ILI9341_8bit_STM();

Actually the connections are:

TFT screen STM32F103C8T6
SS <–> PA4 <–> BOARD_SPI1_NSS_PIN
SCK <–> PA5 <–> BOARD_SPI1_SCK_PIN
MISO <–> PA6 <–> BOARD_SPI1_MISO_PIN
MOSI <–> PA7 <–> BOARD_SPI1_MOSI_PIN

void setup() {
//…
}
void loop() {
// some display instructions
//…
}

The screen lit up, the sketch runs, but there is no display on the screen.

THe TFT screen DC is not connected: is the DC pin not necessary ?

(I use this screen on other devices and it runs correctly)

Thanks