Использование Touch panel на LCD HY32C по SPI на STM32. Как сделать правильно?

#include "mbed.h"

Serial pc(SERIAL_TX, SERIAL_RX);
SPI panel(SPI_MOSI, SPI_MISO, SPI_SCK);
InterruptIn TP_IRQ(PB_12);

DigitalOut TP_CS(PB_6);

void tp_tap(void)
{
	unsigned short X, Y;

	panel.write(0x90);
	X = panel.write(0xFF);
	X<<=8;
	X += panel.write(0x00);
	X=X>>4;
	pc.printf("X=%d,  ", X);

	panel.write(0xD0);
	Y = panel.write(0x00);
	Y<<=8;
	Y += panel.write(0x00);
	Y=Y>>4;
	pc.printf("Y=%d\n", Y);
}


int main(){
	TP_CS=0;
	panel.format(12, 0);
	TP_IRQ.fall(&tp_tap);
	while(1){ }
}