/* vim: set sw=8 ts=8 si : */
/*************************************************************************
Title: linuxfocus frequency counter
Author: guido socher <guido(at)linuxfocus.org>
Copyright: GPL
**************************************************************************/
#include <io.h>
#include <progmem.h>
#include <interrupt.h>
#include <string-avr.h>
#include <stdlib.h>
#include <sig-avr.h>
#include "lcd.h" /* these are the prototypes and defines for lcd.c */
#include "avr-util.h"
#include "uart.h"
/* Input Push Buttons */
#define BUTTON0 PIND6
#define BUTTON0DDR DDRD
#define BUTTON0PIN PIND
#define BUTTON1 PIND3
#define BUTTON1DDR DDRD
#define BUTTON1PIN PIND
/* reset line to 74hc390 */
#define CCLEAR PC4
#define CCLEARDDR DDRC
#define CCLEARPORT PORTC
/* LED0=green */
#define LED0 PC5
#define LED0DDR DDRC
#define LED0PORT PORTC
static char uart_outbuf[UART_RX_BUFFER_SIZE+1];
static unsigned char clock64Hz;
static unsigned char hflag;
static unsigned char mode; /* 0=cout up, 1=freq 1Hz resultion, 2=freq 64Hz resolution */
static unsigned char dmode; /* add 2 zeros behind the display output */
static unsigned char clocklimit;
/* our counter is 16bit wide but we multiply in the fast mode
* with 64 (gate frequency) therefore we need a 24 bit variable */
static unsigned char counterval[3]; /* 24 bit */
static unsigned char counterval_cp[3]; /* 24 bit */
static unsigned char overflowflag;
#define reply_ok() uart_sendstr_P("ok\n")
#define reply_err() uart_sendstr_P("err\n")
/* devide the 24 bit integer unsigned char i[3] by 10 and return
* the value in i[3] */
void divby10(unsigned char *i,unsigned char *rest){
unsigned char loop;
unsigned int tmp; // 16 bit
loop=3;
/* start with highest byte */
*rest=0;
while(loop>0){
tmp=*rest * 256 + i[loop-1];
i[loop-1]=tmp / 10;
*rest=tmp % 10;
loop--;
}
}
/* convert a 3 time 8 bit interger (24 bit=i[3]) to decimal ascii and
* print it using the printfun. */
void longtoascii(void (*printfun)(char),unsigned char *i,unsigned char dodot)
{
char str[14];
unsigned char pos=14;
unsigned char dot=0;
if (dmode==1){
/* take the 2 zeros that will be added into account */
dot=2;
}
do{
/* write a "." every 1000 and 1000000 to make the
* number more readable. 1234 will be 1.234 */
if (dot==3 && dodot==1){
dot=0;
str[pos-1]='.';
pos--;
}else{
divby10(i,&str[pos-1]);
str[pos-1]+= '0';
pos--;
dot++;
}
}while((i[0]|i[1]|i[2]) && pos > 0);
/* now reverse the string and print */
while(pos<14){
(*printfun)(str[pos]);
pos++;
}
if (dmode==1){
(*printfun)('0');
(*printfun)('0');
}
}
/* setup the T1 (PD5) counter to get ready for counting.
* You must call once sei() in the main program */
void cnt_readyforstart(void)
{
/* add: set nand gates */
/* timer should generate interrupt on compate match */
sbi(TIMSK,TOIE1);
/* write high byte first */
outp(0x0,TCNT1H); /* set counter to zero*/
outp(0x0,TCNT1L); /* set counter to zero*/
/* write high byte first */
outp(0xFF,OCR1H); /* set internal compare register to max */
outp(0xFF,OCR1L); /* set internal compare register to max */
outp(0,TCCR1A); /* Timer/Counter1 disconnected from output pin OC1 */
outp(0,TCCR1B); /* off */
}
/* write info about mode to display */
void displaymode(void)
{
lcd_gotoxy(0,1);
if (mode==0){
lcd_puts_P("gate:cont ");
}
if (mode==1){
lcd_puts_P("gate:1sec ");
}
if (mode==2){
lcd_puts_P("gate:1/64sec");
}
}
/* the following function will be called when the counter
* is out of range. This is a 16bit counter! */
SIGNAL(SIG_OVERFLOW1) {
/* add: set nand gates */
overflowflag=1;
outp(0x0,TCNT1H); /* set counter to zero*/
outp(0x0,TCNT1L); /* set counter to zero*/
outp(0,TCCR1B); // stop counter
}
/* we can not use large functions in
* an interrupt handle. Therefore the interrupt routine reads only
* the counter values and the rest is done later via this function
* which is called from the main program */
void handlecounterresult(void){
/* display the result value e.g c:123 */
uart_sendchar('c');
uart_sendchar(':');
lcd_clrscr();
if (overflowflag){
/* overflow */
uart_sendchar('-');
uart_sendchar('1');
lcd_puts_P("overflow");
}else{
if (mode==2) {
/* mult by 64 */
counterval[2]=counterval[1]>>2;
counterval[1]=((counterval[0]>>2)|(counterval[1]<<6));
counterval[0]=counterval[0]<<6;
}
/* make a copy of the counter value */
counterval_cp[2]=counterval[2];
counterval_cp[1]=counterval[1];
counterval_cp[0]=counterval[0];
/* longtoascii sets counterval to zero */
longtoascii(lcd_putc,counterval_cp,1);
longtoascii(uart_sendchar,counterval,0);
if (mode){
/* not for cont count */
lcd_puts_P(" Hz ");
}
if (dmode==1){
/* indicate that the dispaly has 2 additional zeros */
lcd_puts_P("x100");
}
}
uart_sendchar('\n');
displaymode();
clock64Hz=0;
}
/* this function will be called in 64Hz intervals if
* a 4.194304 MHz crystal is used */
SIGNAL(SIG_OVERFLOW0)
{
outp(0,TCNT0); /* clear 64Hz timer value */
if (clock64Hz == clocklimit){
/* read counter */
/* stop 64Hz timer */
outp(0,TCCR0);
//if (mode==1){
/* use this to calibrate the counter result
* for 1 sec gate */
// delay_us(700);
//}else{
/* calibrate for 1/64 sec gate: */
// delay_us(10);
//}
outp(0,TCCR1B); // stop counter
counterval[0]=inp(TCNT1L); /* read low first !! */
counterval[1]=inp(TCNT1H);
hflag=1; /* call the handlecounterresult function */
sbi(LED0PORT,LED0);
}else{
if (clock64Hz==0){
overflowflag=0;
cbi(LED0PORT,LED0);
/* start counter */
/* write high byte first */
outp(0x0,TCNT1H); /* set counter to zero*/
outp(0x0,TCNT1L); /* set counter to zero*/
outp(7,TCCR1B); /* enable 16bin counter from T1 pin */
}
}
clock64Hz++;
}
void changemode(void)
{
outp(0x0,TCNT1H); /* set counter to zero*/
outp(0x0,TCNT1L); /* set counter to zero*/
hflag=0;
clock64Hz=0;
overflowflag=0;
/* clear the 74hc390 divider, clear = 5V */
sbi(CCLEARPORT,CCLEAR);
counterval[0]=0;
counterval[1]=0;
counterval[2]=0;
outp(0,TCCR1B); // stop counter
/* LED off */
sbi(LED0PORT,LED0);
if (mode==0){
/* continious up counting */
outp(0,TCCR0); /* stop 64Hz timer */
outp(0,TCNT0); /* clear timer value */
outp(7,TCCR1B); /* enable counter from T1 pin */
/* LED on */
cbi(LED0PORT,LED0);
}
if (mode==1){
/* one sec gate */
clocklimit=64;
/* start 64Hz timer, clock/256 overflow0 every 256 */
outp(4,TCCR0);
}
if (mode==2){
clocklimit=1;
/* start 64Hz timer, clock/256 overflow0 every 256 */
outp(4,TCCR0);
}
displaymode();
/* enable counting for the 74hc390 divider, clear=0V */
cbi(CCLEARPORT,CCLEAR);
}
int main(void)
{
unsigned char i,rxresult,status;
unsigned int ignorebutton,pausetodisplay;
char cmd;
char *val;
ignorebutton=0;
pausetodisplay=0;
/* initialize display, cursor off */
lcd_init(LCD_DISP_ON);
/* initialize LED as output */
sbi(LED0DDR,LED0);
/* initialize clear line to 74hc390 as output */
sbi(CCLEARDDR,CCLEAR);
/* clear line off */
cbi(CCLEARPORT,CCLEAR);
/* button as digital input */
cbi(BUTTON0DDR,BUTTON0);
cbi(BUTTON1DDR,BUTTON1);
/* initialize rs232 */
uart_init();
/* setup the counter */
cnt_readyforstart();
/* setup the 64Hz timer */
sbi(TIMSK,TOIE0); /* enable T0 overflow0 interrupt */
outp(0,TCNT0); /* start value */
mode=1;
dmode=0;
changemode();
sei(); /* enable interrupt */
lcd_clrscr();
while(1){
if (hflag==1){
handlecounterresult();
hflag=2;
pausetodisplay=65000; // wait a bit for the LCD to show result
}
if (hflag==2 && pausetodisplay==0){
/* prevent flickering of LCD display */
hflag=0;
/* start 64Hz timer */
outp(4,TCCR0);
}
/* for countup mode display result in regular intervalls */
if (mode==0 && pausetodisplay==0){
pausetodisplay=65000;
counterval[0]=inp(TCNT1L); /* read low first !! */
counterval[1]=inp(TCNT1H);
handlecounterresult();
}
rxresult=uart_getrxbufnl(uart_outbuf);
if (ignorebutton==0){
/* button 0 is the mode button */
if (bit_is_clear(BUTTON0PIN,BUTTON0)){
mode++;
if (mode>2) mode=0;
changemode();
ignorebutton=55000; // debounce, ignore button for a while
}
/* button 1 is the clear button
* press twice to add 00 behind the numbers */
if (bit_is_clear(BUTTON1PIN,BUTTON1)){
/* call changemode not to change the mode
* but to clear the 74hc390 counter */
changemode();
/* the second function of this clear button
* is to show 00 on the display */
dmode++;
if (dmode > 1){
dmode=0;
}
outp(0x0,TCNT1H); /* set counter to zero*/
outp(0x0,TCNT1L); /* set counter to zero*/
ignorebutton=55000; // debounce, ignore button for a while
outp(7,TCCR1B); /* enable counter from T1 pin, needed in case there was an overflow */
overflowflag=0;
}
}
if (ignorebutton) ignorebutton--;
if (pausetodisplay) pausetodisplay--;
if (rxresult==0){
continue;
}
/* valid command are:
* */
/* now parse the comands and act on them */
if (strlen(uart_outbuf) < 3) {
reply_err();
continue;
}
if (uart_outbuf[1] != '='){
reply_err();
continue;
}
val=&(uart_outbuf[2]);
cmd=uart_outbuf[0];
status=0;
/* act on the commands */
if (cmd=='h'){
if (*val =='1'){
dmode=1;
status=1;
}
if (*val =='0'){
dmode=0;
status=1;
}
if (*val == '?'){
uart_sendstr_P("h:");
uart_sendchar('0'+ dmode);
uart_sendchar('\n');
continue;
}
}
if (cmd=='c' && *val =='1'){
/* call changemode not to change the mode
* but to clear the 74hc390 counter */
changemode();
outp(0x0,TCNT1H); /* set counter to zero*/
outp(0x0,TCNT1L); /* set counter to zero*/
status=1;
}
if (cmd=='m'){
i=*val;
if (i == '?'){
uart_sendstr_P("m:");
uart_sendchar('0'+ mode);
uart_sendchar('\n');
continue;
}
if (i < '3' && i >= '0'){
mode= i - '0'; // convert to integer;
changemode();
status=1;
}
}
/* command handling done. now return status */
if (status==1){
reply_ok();
}
if (status==0){
reply_err();
}
}
}
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