Python SPI with RA8875 TFT display

[pinguino]

Hi,
I have bought this display http://www.buydisplay.com/default/7-inc ... spi-serial and I want to use it with raspberry. I downloaded the Arduino library from the same web site and I'm triyng to rewrite it in Python, but I'm facing a problem, with the SPI interface. The problem is in the begin function:

Code: Select all

boolean Adafruit_RA8875::begin(enum RA8875sizes s) {
  _size = s;

  if (_size == RA8875_480x272) {
    _width = 480;
    _height = 272;
  } 
  if (_size == RA8875_800x480) {
    _width = 800;
    _height = 480;
  }

  pinMode(_cs, OUTPUT);
  digitalWrite(_cs, HIGH);
  pinMode(_rst, OUTPUT); 
  digitalWrite(_rst, LOW);

  digitalWrite(_rst, LOW);
  delay(100);
  digitalWrite(_rst, HIGH);
  delay(100);
  
  SPI.begin();
#ifdef __AVR__
  SPI.setClockDivider(SPI_CLOCK_DIV128);
  SPI.setDataMode(SPI_MODE0);
#endif
  
  if (readReg(0) != 0x75) {
    return false;
  }
.................
}

uint8_t  Adafruit_RA8875::readReg(uint8_t reg) 
{
  writeCommand(reg);
  return readData();
}

uint8_t  Adafruit_RA8875::readData(void) 
{
  digitalWrite(_cs, LOW);
  SPI.transfer(RA8875_DATAREAD);
  uint8_t x = SPI.transfer(0x0);
  digitalWrite(_cs, HIGH);
  return x;
}

void  Adafruit_RA8875::writeCommand(uint8_t d) 
{
  digitalWrite(_cs, LOW);
  SPI.transfer(RA8875_CMDWRITE);
  SPI.transfer(d);
  digitalWrite(_cs, HIGH);
}

And below the corresponding python code that I wrote:

Code: Select all

#!/usr/bin/python
 
import spidev
import time
import RPi.GPIO as GPIO

GPIO.setwarnings(False)
GPIO.setmode(GPIO.BCM)

RA8875_DATAREAD    =     0x40
RA8875_CMDWRITE    =     0x80
RA8875_DATAWRITE   =     0x00

# Open SPI bus
spi = spidev.SpiDev()
spi.open(0,1)

spi.max_speed_hz = 12000000

rst = 21
cs = 7
GPIO.setup(cs, GPIO.OUT)
GPIO.output(cs, False)
GPIO.setup(rst, GPIO.OUT)
GPIO.output(rst, False)
time.sleep(0.1)
GPIO.output(rst, True)
time.sleep(0.1)

if readReg(0) != 0x75:
  return False


def readReg(reg):
  writeCommand(reg)
  return readData()

def writeCommand(com):
  spi.xfer2([RA8875_CMDWRITE])
  spi.xfer2([com])

def readData():
  spi.xfer2([RA8875_DATAREAD])
  x = spi.xfer([0x0])
  print(x)

The problem is that the readReg(0) always returns 255 (decimal value) and than the program exit.

Anybody can help me to find where I'm wrong?

Thanks