/*************************************************************
*       jl16-2a.c - Demonstrate simple I/O functions of MC68HC908JL16
*
*       This program will cause a 7-segment display to either count up in
*       hexadecimal (0,1,2,...,E,F,0,1,...) or count down in decimal
*       (9,8,...,1,0,9,8,..) depending on whether or not a switch is pressed.
*
*       Port A, bit 1 - input from switch (0 = pressed, 1 = not pressed)
*               When the switch is not pressed, the 7-segment display counts
*               up in hexadecimal. When the switch is pressed, the 7-segment
*               display counts down in decimal.
*       Port B, bits 0-6 - Outputs to data inputs of 74LS374 register.
*               Bit 6 -> segment A, 5->B, ... , 1->F, 0->G
*               A low output bit will cause the LED segment to light up.
*       Port A, bit 5 - Output to positive edge-triggered clock input
*               of 74LS374 register.
*
* Revision History
* Date     Author      Description
* 01/03/05 M. Redekopp Initial Release
* 09/05/05 A. Weber    Modified for JL8 processor
* 01/13/06 A. Weber    Modified for CodeWarrior 5.0
* 08/25/06 A. Weber    Modified for JL16 processor
* 04/23/07 A. Weber    Split example 2 into 2a and 2b
* 08/17/07 A. Weber    Incorporated changes to demo board
* 04/22/08 A. Weber    Added "one" variable to make warning go away
* 04/23/08 A. Weber    Adjusted wait_100ms for 9.8304MHz clock
* 07/09/12 A. Weber    Removed code to set security bytes
* 05/29/13 A. Weber    Renamed CWJL-2a.c to jl16-2a.c
*************************************************************/

#include <hidef.h> /* for EnableInterrupts macro */
#include "derivative.h" /* include peripheral declarations */

unsigned char digit_segs[16] = {
    0x7e,0x30,0x6d,0x79,0x33,0x5b,0x5f,0x70,
    0x7f,0x73,0x77,0x1f,0x4e,0x3d,0x4f,0x47 };
unsigned char delay0;
unsigned char delay1;

void display_digit(int digit);  // prototype
void wait_100ms(void);          // prototype

void main(void) {
    unsigned char one = 1;
    unsigned char up;
    signed char cnt = 0;
    unsigned char i = 0;

    // EnableInterrupts; /* enable interrupts */
    /* include your code here */

    CONFIG1_COPD = 1;        // disable COP reset

    PTAPUE_PTAPUE1 = 1;      // Enable pull-up for switch on PTA1
    DDRA = 0x20;             // Set PTA bit 5 for output
    DDRB = 0x7f;             // Set PTB bits 0-6 for output

    while(one) {             // Loop forever
        display_digit(cnt);

        for (i = 0; i < 5; i++) // wait 500 ms
            wait_100ms();

        up = PTA_PTA1;
        if (up) {                      // if button is not pressed, up = 1
            if (++cnt > 15)            // and we count up in hex
                cnt = 0;
        }
        else {                         // if button is pressed, up = 0
            if (--cnt < 0 || cnt > 9)  // and we count down in decimal
                cnt = 9;
        }
    }
    /* please make sure that you never leave this function */
}

void display_digit(int digit)
{
    PTB = digit_segs[digit] ^ 0xff;   // invert the bits (active low outputs)
    PTA_PTA5 = 1;                     // toggle the clock bit to 1
    PTA_PTA5 = 0;                     // toggle the clock bit to 0
}

/*
  Note: this delay routine only works if the the delay0 and delay1
  variables are NOT located in the RAM zero page (extended addressing used).
*/

/*
  wait_100ms - Delay about 100msec.
*/
void wait_100ms(void)
{
    asm {
        ; The following code delays 100 milliseconds by looping.
        ; Total time is
        ; 2+4 + 79 * (1+4 + 256 * (4+1+4+3) + 4+1+4+3) = 244,037 cycles
        ; A 9.8304MHz external clock gives an internal CPU clock of
        ; 2.4576MHz (407ns/cycle).  Delay is then 99.3 milliseconds.
                lda     #97            ; 2 clocks
                sta     delay1         ; 4 clocks
        m1:     clra                   ; 1 clocks
                sta     delay0         ; 4 clocks
        m0:     lda     delay0         ; 4 clocks
                deca                   ; 1 clocks
                sta     delay0         ; 4 clocks
                bne     m0             ; 3 clocks
                lda     delay1         ; 4 clocks
                deca                   ; 1 clocks
                sta     delay1         ; 4 clocks
                bne     m1             ; 3 clocks
    }
}