/*
  PCF2111 LCD driver example code. Used with a dual-chip module (each chip
  drives 8 digits). Data and Clock lines are shared.
  
  The code displays a scrolling message on the 16 digit 7 segment LCD.
  A hexadecimal font (for this particular segment setup) extended with
  several characters is included.
  
  segment map: A or B indicates A/B register
  
      a1
     ---
    |   |a3
  b1| a2|
     ---
    |   |a4
  b2|   |
     --- __
     b4  \/b3
      
  docs:
  LOCM3 docs: http://libopencm3.org/docs/latest/stm32f1/html/
  PCF2111 datasheet: https://www.nxp.com/docs/en/data-sheet/PCF21XXC_FAM.pdf
  
  Copyright 2020 polprog.net. Released on 3-clause BSD. See COPYING file
  for details
 */


#define STM32F1

#include <libopencm3/stm32/rcc.h>
#include <libopencm3/stm32/gpio.h>


/* PCF2111 module IO */
#define LCD_PORT GPIOA
#define LCD_CLK  GPIO0
#define LCD_DATA GPIO2
#define LCD_CS1  GPIO3
#define LCD_CS2  GPIO1


/* test font 
uint8_t font[] = {
		  0b10000000,
		  0b01000000,
		  0b00100000,
		  0b00010000,
		  0b00001000,
		  0b00000100,
		  0b00000010,
		  0b00000001,
		  0b11110000,
		  0b00001111
		  };*/

/* real font */
uint8_t font[] = {
		  //b4-b1 a4-a1
		  0b10111101,//0
		  0b00001100,//1
		  0b10100111,//2
		  0b10001111,//3
		  0b00011110,//4
		  0b10011011,//5
		  0b10111011,//6
		  0b00001101,//7
		  0b10111111,//8
		  0b10011111,//9
		  0b00111111,//A 10
		  0b10111010,//b 11
		  0b10110001,//C 12
		  0b10101110,//d 13
		  0b10110011,//E 14
		  0b00110011,//F 15
		  // letters
		  0b00111010,//H 16
		  0b00111110,//k 17
		  0b10110010,//t 18
		  0b00110111,//P 19
		  0b10110000,//L 20
 		  0b00101010,//N 21
		  0b00000000,//space 22
		  0b01000100,//exclam 23
		  
		  };
/* structure for holding the PCF2111 data */
struct pcf2111 {
  uint32_t rega, regb;
};

void pcf2111_putchar(char c, uint8_t pos, struct pcf2111 *where){
  where->rega &= ~(0x0F << (pos*4));
  where->rega |= (font[c] & 0x0F) << (pos*4);
  where->regb &= ~(0x0F << (pos*4));
  where->regb |= ((font[c] & 0xF0) >> 4) << (pos*4);

}

  

/* PCF2111 module GPIO init routine */
void pcf2111_gpio_init(){
    rcc_periph_clock_enable(RCC_GPIOA);

  gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_2_MHZ,
		GPIO_CNF_OUTPUT_PUSHPULL, GPIO0 | GPIO1 | GPIO2 | GPIO3);
}


/* PCF2111 module data tx routine
   uint32_t data - 32 data bits
   uint8_t reg   - A or B register 
   uint8_t cs    - CS1 or CS2 select
 */
void pcf2111_send(uint32_t data, uint8_t reg, uint8_t cs){
  if(cs) gpio_set(LCD_PORT, LCD_CS2);
  else gpio_set(LCD_PORT, LCD_CS1);
  
  //1st clock with data=0
  gpio_clear(LCD_PORT, LCD_DATA);
  gpio_set(LCD_PORT, LCD_CLK);
  for(int k = 0; k < 100; k++) __asm__("nop");
  gpio_clear(LCD_PORT, LCD_CLK);
  for(int k = 0; k < 100; k++) __asm__("nop");
  
  //32 clocks with data, clks 2-33
  for(uint8_t j = 0; j < 32; j++){
    gpio_set(LCD_PORT, LCD_CLK);
      
    if((data & (1 << j)) == 1<<j) gpio_set(LCD_PORT, LCD_DATA);
    else gpio_clear(LCD_PORT, LCD_DATA);
      
    for(int k = 0; k < 100; k++) __asm__("nop");
    gpio_clear(LCD_PORT, LCD_CLK);
    for(int k = 0; k < 100; k++) __asm__("nop");
  }
  //clock 34, databit 33 (load bit)
  

  gpio_set(LCD_PORT, LCD_CLK);
  for(int k = 0; k < 100; k++) __asm__("nop");
  if(reg) gpio_set(LCD_PORT, LCD_DATA);
  else gpio_clear(LCD_PORT, LCD_DATA);
  for(int k = 0; k < 100; k++) __asm__("nop");
  gpio_clear(LCD_PORT, LCD_CLK);
  for(int k = 0; k < 100; k++) __asm__("nop");


  gpio_clear(LCD_PORT, LCD_DATA);

  if(cs) gpio_clear(LCD_PORT, LCD_CS2);
  else gpio_clear(LCD_PORT, LCD_CS1);
  
  //bit 34 (clock 35 on datasheet, with CS low, "glitch")
  gpio_toggle(LCD_PORT, LCD_CLK);
  for(int k = 0; k < 100; k++) __asm__("nop");
  gpio_toggle(LCD_PORT, LCD_CLK);
  for(int k = 0; k < 100; k++) __asm__("nop");

}

//hACK thE PLAnEt
uint8_t message[] = {16, 10, 12, 17, 22, 18, 16, 14, 22, 19, 20, 10, 21, 14, 18, 23, 22, 22, 22, 22, 22};

int main(){
  //setup port C
  rcc_periph_clock_enable(RCC_GPIOC);
  gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_2_MHZ,
		GPIO_CNF_OUTPUT_PUSHPULL, GPIO13);
 
  pcf2111_gpio_init();

  struct pcf2111 chip1 = {0, 0};
  struct pcf2111 chip2 = {0, 0};

  
  for(int a = 0; a < 8; a++){
    gpio_toggle(GPIOC, GPIO13);
    pcf2111_putchar(message[a] , a, &chip1);
    pcf2111_putchar(message[a+8], a, &chip2);
    
    pcf2111_send(chip1.rega, 0, 0);
    pcf2111_send(chip1.regb, 1, 0);
    pcf2111_send(chip2.rega, 0, 1);
    pcf2111_send(chip2.regb, 1, 1);
    
    for(int i = 0; i < 50000; i++) __asm__("nop");
  }

  int x = 0;
  while(1){
    for(int a = 0; a < 8; a++){
      gpio_toggle(GPIOC, GPIO13);
      pcf2111_putchar(message[(a+x)%21], a, &chip1);
      pcf2111_putchar(message[(a+x+8)%21], a, &chip2);
    }
    x++;
    pcf2111_send(chip1.rega, 0, 0);
    pcf2111_send(chip1.regb, 1, 0);
    pcf2111_send(chip2.rega, 0, 1);
    pcf2111_send(chip2.regb, 1, 1);
    for(int i = 0; i < 250000; i++) __asm__("nop");
  }
}