Initialising LCD eadip203-6 using functions over Beaglebone Black SPI - c

Question

I am trying to write down the functions for the LCD initialisation with the LCD screen eadip203-6 using SPI on beaglebone black. I am facing some problems as I am trying to execute the functions, initially the screen gets stuck, then if I comment the above functions and see what happens the cursor still blinks. I am trying to do this from page number 29,30 and 33,34,35,36,37,38,39,40 of the data sheet. I have not written all the 16 functions. But written a few of the starting ones.Now as soon as I execute the last two functions from the above code the screen goes blank. Can you please tell me where am I going wrong in this? Also can you please tell me about the CGRAM,SEGRAM, DDRAM and the busy flag.
#include <stdint.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <getopt.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/types.h>
#include <linux/spi/spidev.h>
#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
static void transfer(int fd, uint16_t* tx, uint8_t cs);
void init_display(int fd);
void clear_display_func(int fd);
void return_home_func(int fd);
void power_mode_func(int fd);
void entry_mode_set_func(int fd);
void display_on_off_func(int fd);
void extended_function_set_func(int fd);
void cursor_display_shift_bias_func(int fd);
static void pabort(const char *s)
{
perror(s);
abort();
}
static const char *device = "/dev/spidev2.1";
static uint8_t mode=3;
static uint8_t bits = 8;
static uint32_t speed = 40000;
static uint16_t delay;
void clear_display_func(int fd)
{
int ret;
uint16_t clear_display[]={0xF8,0x80,0x00};
for(ret=0; ret<3; ret++)
{
transfer(fd,&clear_display[ret],0);
usleep(2000);
}
}
void return_home_func(int fd)
{
int ret;
uint16_t return_home[]={0xF8,0x40,0x00};
for(ret=0; ret<3; ret++)
{
transfer(fd,&return_home[ret],0);
usleep(2000);
}
}
void power_mode_func(int fd)
{
int ret;
uint16_t power_mode[]={0xF8,0xC0,0x00};
for(ret=0; ret<3; ret++)
{
transfer(fd,&power_mode[ret],0);
usleep(2000);
}
}
void entry_mode_set_func(int fd)
{
int ret;
uint16_t entry_mode_set[]={0xF8,0xE0,0x00,
0xF8,0x60,0x00};
for(ret=0; ret<6; ret++)
{
transfer(fd,&entry_mode_set[ret],0);
usleep(2000);
}
}
void display_on_off_func(int fd)
{
int ret;
uint16_t display_on_off[]={0xF8,0xF0,0x00};
for(ret=0; ret<3; ret++)
{
transfer(fd,&display_on_off[ret],0);
usleep(2000);
}
}
void extended_function_set_func(int fd)
{
int ret;
uint16_t extended_function_set[]={0xF8,0xD0,0x00};
for(ret=0; ret<3; ret++)
{
transfer(fd,&extended_function_set[ret],0);
usleep(2000);
}
}
void cursor_display_shift_bias_func(int fd)
{
int ret;
uint16_t cursor_display_shift_bias[]={0xF8,0x50,0x80};
for(ret=0; ret<3; ret++)
{
transfer(fd,&cursor_display_shift_bias[ret],0);
usleep(2000);
}
}
static void transfer(int fd, uint16_t* tx, uint8_t cs){
int ret;
uint16_t rx[ARRAY_SIZE(tx)] = {0, };
struct spi_ioc_transfer tr = {
.tx_buf = (unsigned long)tx,
.rx_buf = 0,
.len = 1,
.delay_usecs = delay,
.speed_hz = speed,
.bits_per_word = bits,
.cs_change=cs,
};
printf("%u", cs);
ret = ioctl(fd, SPI_IOC_MESSAGE(1), &tr);
if (ret < 1)
pabort("can't send spi message");
puts("");
}
static void print_usage(const char *prog)
{
printf("Usage: %s [-DsbdlHOLC3]\n", prog);
puts(" -D --device device to use (default /dev/spidev1.1)\n"
" -s --speed max speed (Hz)\n"
" -d --delay delay (usec)\n"
" -b --bpw bits per word \n"
" -l --loop loopback\n"
" -H --cpha clock phase\n"
" -O --cpol clock polarity\n"
" -L --lsb least significant bit first\n"
" -C --cs-high chip select active high\n"
" -3 --3wire SI/SO signals shared\n");
exit(1);
}
static void parse_opts(int argc, char *argv[])
{
while (1) {
static const struct option lopts[] = {
{ "device", 1, 0, 'D' },
{ "speed", 1, 0, 's' },
{ "delay", 1, 0, 'd' },
{ "bpw", 1, 0, 'b' },
{ "loop", 0, 0, 'l' },
{ "cpha", 0, 0, 'H' },
{ "cpol", 0, 0, 'O' },
{ "lsb", 0, 0, 'L' },
{ "cs-high", 0, 0, 'C' },
{ "3wire", 0, 0, '3' },
{ "no-cs", 0, 0, 'N' },
{ "ready", 0, 0, 'R' },
{ NULL, 0, 0, 0 },
};
int c;
c = getopt_long(argc, argv, "D:s:d:b:lHOLC3NR", lopts,
NULL);
if (c == -1)
break;
switch (c) {
case 'D':
device = optarg;
break;
case 's':
speed = atoi(optarg);
break;
case 'd':
delay = atoi(optarg);
break;
case 'b':
bits = atoi(optarg);
break;
case 'l':
mode |= SPI_LOOP;
break;
case 'H':
mode |= SPI_CPHA;
break;
case 'O':
mode |= SPI_CPOL;
break;
case 'L':
mode |= SPI_LSB_FIRST;
break;
case 'C':
mode |= SPI_CS_HIGH;
break;
case '3':
mode |= SPI_3WIRE;
break;
case 'N':
mode |= SPI_NO_CS;
break;
case 'R':
mode |= SPI_READY;
break;
default:
print_usage(argv[0]);
break;
}
}
}
int main(int argc, char *argv[])
{
int ret = 0;
int fd;
parse_opts(argc, argv);
fd = open(device, O_RDWR);
if (fd < 0)
pabort("can't open device");
/*
* spi mode
*/
ret = ioctl(fd, SPI_IOC_WR_MODE, &mode);
if (ret == -1)
pabort("can't set spi mode");
ret = ioctl(fd, SPI_IOC_RD_MODE, &mode);
if (ret == -1)
pabort("can't get spi mode");
/*
* bits per word
*/
ret = ioctl(fd, SPI_IOC_WR_BITS_PER_WORD, &bits);
if (ret == -1)
pabort("can't set bits per word");
ret = ioctl(fd, SPI_IOC_RD_BITS_PER_WORD, &bits);
if (ret == -1)
pabort("can't get bits per word");
/*
* max speed hz
*/
ret = ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed);
if (ret == -1)
pabort("can't set max speed hz");
ret = ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed);
if (ret == -1)
pabort("can't get max speed hz");
printf("spi mode: %d\n", mode);
printf("bits per word: %d\n", bits);
printf("max speed: %d Hz (%d KHz)\n", speed, speed/1000);
init_display(fd);
usleep(20000);
clear_display_func(fd);
usleep(20000);
return_home_func(fd);
usleep(20000);
power_mode_func(fd);
usleep(20000);
entry_mode_set_func(fd);
usleep(20000);
display_on_off_func(fd);
usleep(20000);
extended_function_set(fd);
usleep(20000);
cursor_display_shift_bias_func(int fd);
usleep(20000);
close(fd);
return ret;
}