/*
 * main.c
 *
 * Description:
 * This is driver for the ISD4003 chip using SPI.
 *
 * Author: Martin Dubuc
 *
 * Creation date: January 4, 2001
 */

#include <16f877.h>

/* Microcontroller configuration bits */
#fuses HS,NOPROTECT,NOWDT,BROWNOUT,PUT,NOLVP

#ORG 0x1F00,0x1FFF {} /* Reserve memory for bootloader for the 8k 16F876/7 */

#device PIC16F877 *=16 /* Allow RAM to expand beyond 256 bytes */

/* The 20_MHZ_CLOCK define is used to indicate whether we are using
   a 4 MHz or 20 MHz clock */
#undef 20_MHZ_CLOCK

/* Set the clock speed. */
#ifdef 20_MHZ_CLOCK
#use delay(clock=20000000)
#else
#use delay(clock=4000000)
#endif

/* Directive for RS-232 interface */
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7)

/* ISD4003 definitons */
// Pin definition
#define ISD_SS (PIN_A5)
#define ISD_MOSI (PIN_C5)
#define ISD_MISO (PIN_C4)
#define ISD_SCLK (PIN_C3)
#define ISD_INT (PIN_B0)
#define ISD_RAC (PIN_B1)

// Opcode defintion

#define ISD_OPCODE_POWERUP    (0b00100)
#define ISD_OPCODE_SETPLAY    (0b00111)
#define ISD_OPCODE_PLAY       (0b01111)
#define ISD_OPCODE_SETREC     (0b00101)
#define ISD_OPCODE_REC        (0b01101)
#define ISD_OPCODE_SETMC      (0b10111)
#define ISD_OPCODE_MC         (0b11111)
#define ISD_OPCODE_STOP       (0b01100)
#define ISD_OPCODE_STOPPWRDN  (0b01000)
#define ISD_OPCODE_RINT       (0b01100)

// Following are time definitions. All values are in milliseconds
// except when stated otherwise.

#define TPUD (50)

#define TRAC (400)

#define TRACLO (50)

#define TRACM (250) // microseconds

#define TRACML (31250) // 31.25 microseconds

/* Application definitions */
#define RECORD_LED (PIN_B2)
#define RECORD_BUTTON (PIN_D0)
#define PLAY_BUTTON (PIN_D1)

#define INFINITE (0xffff)

/* Type definitions */
typedef short int BIT;

typedef int uint8_t;

typedef long uint16_t;

/* Variable definitions */
BIT ovm, eom;
BOOLEAN record = false;
BOOLEAN play = false;

/* Public interface */
void main(void);

void isd_record(uint16_t address);

void isd_play(uint16_t address);

void isd_stop(void);

void isd_send_command(uint8_t command, uint16_t address);

void isd_read(uint16_t *data);

#int_ext
void ext_interrupt_handler(void);

void
main(void) {
  uint16_t address = 0x0;
  int i;

  /* Initialization */
  enable_interrupts(GLOBAL);
  enable_interrupts(INT_EXT);

  ext_int_edge(H_TO_L);

  /* set direction of ports, All Out */
  set_tris_a(0b00110010);
  set_tris_b(0b00000011); /* Port B0 and B1 are inputs. B3 is
                             output. */
#if 1
  set_tris_c(0b00010000);
#endif

  output_low(RECORD_LED);

  output_high(ISD_SS);
  setup_spi(SPI_MASTER | SPI_H_TO_L | SPI_CLK_DIV_16);

  for ( ; ; ) {
    if (!input(RECORD_BUTTON) && !record && !play) {
       if (play) {
         isd_stop();
       }

       isd_record(address);
    }
    if (input(RECORD_BUTTON) && record) {
      isd_stop();
    }

    if (!input(PLAY_BUTTON) && !play && !record) {
      // Play recorded stream
      isd_play(address);
    }
    if (input(PLAY_BUTTON) && play) {
      isd_stop();
    }
  }
} /* main */

void
isd_record(uint16_t address) {
  printf("record\r\n");

  output_high(RECORD_LED);

  record = true;

  isd_send_command(ISD_OPCODE_POWERUP, 0);

  delay_ms(TPUD);

  isd_send_command(ISD_OPCODE_POWERUP, 0);

  delay_ms(2 * TPUD);

  isd_send_command(ISD_OPCODE_SETREC, address);

  isd_send_command(ISD_OPCODE_REC, 0);
} // isd_record

void
isd_play(uint16_t address) {
  printf("play\r\n");

  play = true;

  isd_send_command(ISD_OPCODE_POWERUP, 0);

  delay_ms(TPUD);

  isd_send_command(ISD_OPCODE_SETPLAY, address);

  isd_send_command(ISD_OPCODE_PLAY, 0);
} // isd_play

void
isd_stop(void) {
  printf("stop\r\n");

  output_low(RECORD_LED);

  play = false;
  record = false;

  isd_send_command(ISD_OPCODE_STOP, 0);
} // isd_stop

void
isd_send_command(uint8_t command, uint16_t address) {
  output_low(ISD_SS);
  spi_write(address & 0xff);
  spi_write(((address & 0xff00) >> 3) | command);
  output_high(ISD_SS);
} // isd_send_command

void
isd_read(uint16_t *data) {
  uint8_t b1, b2;

  output_low(ISD_SS);
  b1 = spi_read();
  b2 = spi_read();
  output_high(ISD_SS);

  *data = (b1 << 8) | b2;
} // isd_read

#int_ext
void ext_interrupt_handler(void) {
  uint16_t data;

  // The external interrupt is triggered when there OVM or EOM occurs.
  // If pin is set to low, then OVF or EOM is detected.

  printf("OVF or EOM\r\n");

  play = false;

  // To read the OVM and EOM flags, issue the RINT command.
  isd_send_command(ISD_OPCODE_RINT, 0);

  isd_read(&data);

  ovm = data >> 15;
  eom = (data >> 14) & 1;

  printf("Interrupt status = 0x%02x\r\n", data);
} // ext_interrupt_handler