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pendexgabo
Joined: 07 Mar 2005
Posts: 2
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| what is CCP_PWM_PLUS_3 |
 Posted: Mon Mar 07, 2005 11:50 am |
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hi, first I want to apologize for my English, all that I write in this forum is with the help of a translator.
seeing the help of the CCS, I find like option of configuration of the PWM, the option CCP_PWM_PLUS_3, but in the help of PCW I canīt find answer about so that this configuration is used.
if somebody could inform that it is this option.
thanks to all
for if to somebody it interests him, I am carrying out a project with the integrated ADXL202 (2-Axis Acceleration Sensor), all info is in Spanish but there is good graphics of some test and the calibration.
for some info visit www.nodolujan.com.ar/gabrielsosa
bye |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Mar 07, 2005 12:50 pm |
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CCS provides two methods to set the 10-bit PWM duty cycle.
In one method, you give a 16-bit value to the set_pwm_duty1()
function. (The lower 10 bits is the duty cycle).
In the other method, you give an 8-bit value to the set_pwm_duty1().
This sets the upper 8 bits of the 10-bit value. Then the lower 2 bits are
set by giving a special constant value to the setup_ccp1() function.
These constants are:
| Code: |
CCP_PWM lower 2 bits = 0
CCP_PWM_PLUS_1 lower 2 bits = 1
CCP_PWM_PLUS_2 lower 2 bits = 2
CCP_PWM_PLUS_3 lower 2 bits = 3 |
Both methods give the same result. Compile the program below
and run it. It programs the duty cycle with each method, and then
it reads the PWM registers and displays these results:
CCPR1L register value = 40
CCP1CON register value = 03
CCPR1L register value = 40
CCP1CON register value = 03
It's easier to use the 10-bit method. I think the CCP_PWM_PLUS_x
method was probably used by the earliest versions of the compiler.
Then they got the idea of using the 10-bit method and added it.
| Code: | #include <16F877.H>
#fuses XT, NOWDT, NOPROTECT, BROWNOUT, PUT, NOLVP
#use delay(clock = 4000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, ERRORS)
#byte CCPR1L = 0x15
#byte CCP1CON = 0x17
void display_CCP_regs(void)
{
printf("CCPR1L register value = %x\n\r", CCPR1L);
printf("CCP1CON register value = %x\n\r", (CCP1CON >> 4) & 0x3);
}
//============================
main()
{
// Program the 10-bit duty cycle using the "long" parameter method.
setup_ccp1(CCP_PWM);
set_pwm1_duty(0x103); // Give a 10 bit value to the function.
display_CCP_regs();
// Program the 10-bit duty cycle using 8 bit method.
setup_ccp1(CCP_PWM_PLUS_3); // Set the LSB = 3
set_pwm1_duty(0x40); // Give an 8-bit value to the function.
display_CCP_regs();
while(1);
} |
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pendexgabo
Joined: 07 Mar 2005
Posts: 2
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| what is CCP_PWM_PLUS_3 |
| Posted: Mon Mar 07, 2005 3:47 pm |
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I could understand.
do I want to wonder, is one able to what I write?
tanks for all |
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