I can't read keydatas (buttons' press values) with SPI between XMC4800 and STLED316 - spi

Question

I use SPI communication between XMC4800 and STLED316 led controller. I can write datas to the display on STLED316.However, I can't read keydatas (by keyscan feature of STLED, it is written by STLED316 datasheet). I have some codes for write and read. I suppose command address or register address to send a byte to STLED is wrong. I couldn't figure out if they are the problem or something else. I simplified the codes. I used SPI_MASTER API for communication. write_7segg is working but can't use keydata's specific bits to use button press values (0,1). I need to use key press (keydata) values to change something on the display. If someone worked with STLED316 before, it maybe more understandable. Finally, STLED316 has a 5-digit display and 5 buttons with keyscan feature. read[0] = STLED316_DATA_RD = 0x40, read[1] = STLED316_READ_PAGE = 0x08, keydata[0] = STLED316_ADDR_KEY_DATA1 = 0x01. Here the codes are:
keydata = read_keyscan();
if ((((keydata) & 0x01) == 1) && (current_mode == 0)) {
write_7segg(4, arServo_Numbers[0]);
write_7segg(3, arServo_Numbers[0]);
write_7segg(2, arServo_Characters[23]);
write_7segg(1, arServo_Numbers[0]);
write_7segg(0, arServo_Characters[15]);
}
void write_7segg(unsigned char DisplayNumber, unsigned char Segments) {
// DIGITAL_IO_SetOutputLow(&DIGITAL_IO_0);
Buffer[0] = DisplayNumber;
Buffer[1] = Segments;
DIGITAL_IO_SetOutputLow(&DIGITAL_IO_8);
SPI_MASTER_Transmit(&SPI_MASTER_01,Buffer, 2);
DIGITAL_IO_SetOutputHigh(&DIGITAL_IO_8);
uint8_t readData(uint8_t address){
uint8_t sendByte = read[0]|read[1]|address;
uint8_t readByte = 0;
DIGITAL_IO_SetOutputLow(&DIGITAL_IO_8);
SPI_MASTER_Transfer(&SPI_MASTER_01,&sendByte, &readByte, 1);
DIGITAL_IO_SetOutputHigh(&DIGITAL_IO_8);
return readByte;
}
uint16_t read_keyscan(void){
uint16_t keyState = 0;
keyState = readData(keys[1]) << 8;
keyState = readData(keys[0]);
return keyState;
}