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zachavm
Joined: 23 Mar 2006
Posts: 9
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| Undefined Identifier TMR1H |
 Posted: Sun Mar 25, 2007 5:30 pm |
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Hi, I'm trying to use timer1 to read the frequency of an incoming square wave signal. However, when I try to read the TMR1H and TMR1L registers, I get the error "Undefined Identifier TMR1H". Shouldn't I be able to read this? Here's my code for the project. A lot of this can be ignored as it's simply outputting to an LCD. Focus on the code highlighted by "***********".
Note: I made a similar thread earlier about a different problem when I was using a different method to execute this. I'm not trying a different technique for Frequency measurement.
| Code: | #include "18F458.H"
#fuses HS,NOWDT,NOPUT,NOLVP,NOBROWNOUT
#use delay(clock=20000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7)
#include <string.h>
#include <stdlib.h>
#use fast_io(D)
// Global Variables
int i;
int16 speed = 50;
char mystr[10];
int overflow_cnt =0;
unsigned long int wheel_counts, wheel_test, last_counts, delta_counts, sensor_freq;
/*unsigned long int end_time = 0, start_time = 0;
unsigned long int pulse_ticks = 0;
unsigned long int actual_speed = 0;
unsigned int32 cnt = 0;*/
int b1 = 0;
int b2 = 0;
int screenChanged = 1;
//sends a data byte to the LCD
void send_data(char e)
{
output_bit(PIN_C4, 1); //RS is set high so that the LCD is in Data Mode
output_B(e);
delay_us (20); //Delays for one microsecond
output_bit(PIN_C5, 1);
delay_us (20); //Delays for one microsecond to give the LCD time to read the data
output_bit(PIN_C5, 0); //enable is low. brought high to put on data
delay_us (20);
}
//sends a command to the LCD
void send_command(char f)
{
output_bit(PIN_C4, 0); //RS is set low so that the LCD is in Command Mode
output_B(f); //turns on display and adds cursor, underline, and cursor blink
delay_us (20);
output_bit(PIN_C5, 1); //trows enable low to send command to LCD
delay_us (20); //Delays for one microsecond to give the LCD time to read the data
output_bit(PIN_C5, 0); //enable is brought back to high
delay_us (20);
}
//***************************************
#int_TIMER2
TIMER2_isr() //interupt for timer1 overflow
{
//makes sure the received count is the most recent
wheel_counts = TMR1H << 8;
wheel_counts += TMR1L;
wheel_test = TMR1H << 8;
wheel_test = TMR1L;
if (wheel_counts != wheel_test)
{
wheel_counts = TMR1H << 8;
wheel_counts += TMR1L;
}
delta_counts = (int32) (wheel_counts - last_counts);
sensor_freq = 1000 * delta_counts; //frequency of input signal
last_counts = wheel_counts;
}
//*********************************************
void main()
{
//initiates the LCD
delay_ms(500);
output_bit(PIN_C5, 0); //enable is low. brought high to put on data
send_command(0x0C);
send_command(0x38);
send_command(0x01);
//activate and setup LCD
delay_ms (100);
//send to LCD "Hello World"
send_data('W');
send_data('e');
send_data('l');
send_data('c');
send_data('o');
send_data('m');
send_data('e');
delay_ms(2000); //2 second delay
send_command(0x01); //clears the screen
delay_ms(5);
//************************************
//initialization of timer1 and timer2
setup_timer_1(T1_EXTERNAL|T1_DIV_BY_1);
setup_timer_2(T2_DIV_BY_4, 125, 10); //Timer2 interrupt every 1 ms
enable_interrupts(INT_TIMER1);
enable_interrupts(INT_TIMER2);
enable_interrupts(INT_EXT);
enable_interrupts(global);
//***********************************
while(1)
{
//checks to see if button 1 is pressed (speed up)
if(!input(PIN_C0) && b1 == 1)
{
if (speed < 2000)
speed += 50;
b1=0;
screenChanged = 1;
}
if(input(PIN_C0))
b1 = 1;
//checks to see if button 2 is pressed (speed down)
if(!input(PIN_C1) && b2 == 1)
{
if (speed > 50)
speed -= 50;
b2 = 0;
screenChanged = 1;
}
if(input(PIN_C1))
b2 = 1;
//makes sure the screen get's refreshed if no button is pushed
++cnt;
if(cnt > 1000)
{
screenChanged = 1;
cnt = 0;
}
//outputs the speed to the LCD
if (screenChanged == 1)
{
send_command(0x80); //clears the display
sprintf(mystr, "%lu", speed); //converts the int to a character string
i = 0; //loop that writes the number to the LCD
while(mystr[i] != NULL)
{
send_data(mystr[i]);
i++;
}
send_data('R');
send_data('P');
send_data('M');
send_data(' ');
send_data(' ');
send_data(' ');
send_data(' ');
send_command(0xC0); //shift writing position to second line
sprintf(mystr, "%lu", sensor_freq); //converts the int to a character string
i = 0; //loop that writes the number to the LCD
while(mystr[i] != NULL)
{
send_data(mystr[i]);
i++;
}
send_data('R');
send_data('P');
send_data('M');
send_data(' ');
send_data(' ');
send_data(' ');
send_data(' ');
screenChanged = 0;
}
} //end while
} // end main
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Sun Mar 25, 2007 5:50 pm |
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| Quote: |
However, when I try to read the TMR1H and TMR1L registers, I get the
error "Undefined Identifier TMR1H". Shouldn't I be able to read this ? |
The compiler doesn't know what those symbols are. You need to tell it.
Here, someone has typed in all the register declaration statements.
You can save it out as 18F458_regs.h and #include it in your program.
http://www.ccsinfo.com/forum/viewtopic.php?t=14755 |
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SimpleAsPossible
Joined: 19 Jun 2004
Posts: 21
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| Generally speaking, for stuff like this... |
| Posted: Sun Mar 25, 2007 5:55 pm |
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Go to 41159D.pdf (for PIC18F458), go to page 47 (page 49 of the PDF file) and look at Table 4.1 Special Function Register Map, TMR1H is FCFh and TMR1L is FCEh. Add this near the top of your file:
| Code: | #byte TMR1H = 0xFCF
#byte TMR1L = 0xFCE |
And you'll be off and running.
Obviously, if someone has written a register header file, you can use it instead. It's just useful to know how to make it yourself too. |
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