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Guest
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| PICKIT 1 & 12F675 programing |
 Posted: Fri May 21, 2004 9:13 pm |
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Hello,
Im new to PICs and have been trying to program a 12F675 using a PICKit 1 flash programer from microchip.
This is an example of the code I am using to attempt to make pin 2 on the chip go high:
#include <12f675.h>
#use delay (clock=400000)
void main()
{
output_high (PIN_A0);
}
It compiles ok, and creates a HEX file. I then use the PICKit tool to write the HEX file to the PIC.
I then moved the PIC to my breadboard connected +5v to pin 1 and pin 8 to GND, but PIN 2 never goes high.
Am I doing something wrong?
Thanks
Eric. |
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Haplo
Joined: 06 Sep 2003
Posts: 659
Location: Sydney, Australia
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| Posted: Fri May 21, 2004 9:58 pm |
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Just a quick note: never let your code flow past the end of main(). Add this line under the output_high():
while (1); |
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languer
Joined: 09 Jan 2004
Posts: 144
Location: USA
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| Posted: Sat May 22, 2004 12:04 am |
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Eric,
You have to enable the pins for digital IO operation, example follows.
| Code: | /////////////////////////////////////////////////////////////////////////
/// Example program to blink an LED connected to GP0
///
/// Fuses: LP,XT,INTRC,HS,NOWDT,WDT,CPD,NOCPD,PROTECT,NOPROTECT,NOMCLR
/// Fuses: MCLR,PUT,NOPUT,RC,EC,RC_IO,INTRC_IO,BROWNOUT,NOBROWNOUT
/// Fuses: BANDGAPLOW,BANDGAPHIGH
/////////////////////////////////////////////////////////////////////////
// Preprocessor
#include <12F675.h>
#device ADC=10
#fuses INTRC,NOWDT,NOPUT,NOPROTECT,NOCPD,NOMCLR
#use delay(clock=4000000)
#define GP0 PIN_A0
#define GP1 PIN_A1
#define GP2 PIN_A2
#define GP3 PIN_A3
#define GP4 PIN_A4
#define GP5 PIN_A5
void init()
{
set_tris_a( 0b11111110 ); // set GP0 output, all other inputs
setup_comparator( NC_NC_NC_NC ); // disable comparators
setup_adc_ports( NO_ANALOGS ); // disable analog inputs
setup_adc( ADC_OFF ); // disable A2D
}
// Main Program
main()
{
init();
while ( TRUE ) // blink LED
{
output_high( GP0 ); // turn LED on
delay_ms( 250 ); // wait 250ms
output_low( GP0 ); // turn LED off
delay_ms( 250 ); // wait 250ms
}
} |
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brokebit
Joined: 21 May 2004
Posts: 3
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| Still nothing |
| Posted: Sat May 22, 2004 1:32 pm |
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Languer,
I cut and pasted your code example, it compiled fine, and I was able to sucesfully write it to the pic using the PICKit programer; however, It still will not flash any LED.
Very strange. Is there somewhere I can look for documentation on some of the Pre-Processor commands such as FUSE and DEVICE ADC? I have the CCS Refrence manual, but it does not go into to much detail.
Also, when wiring this up on a breadboard, I did not include any external components. Only a +5V source on pin 1, and GND on pin 8.
THoughts, comments, suggestions welcome.
Eric. |
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Stuck in Fujisawa
Guest
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| Clock? |
| Posted: Sat May 22, 2004 11:27 pm |
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| What is your clock? 400 kHZ, or should it really be 4 MHz? Just a thought... |
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languer
Joined: 09 Jan 2004
Posts: 144
Location: USA
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| Corrections to original code |
| Posted: Sun May 23, 2004 12:48 am |
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The following corrections were made to original code to blink GP1 on the PICKit (not GP0, as GP0 is used in for the A2D section).
| Code: | | #fuses INTRC_IO,NOWDT,NOPUT,NOPROTECT,NOCPD,NOMCLR |
note that I missed the _IO originally.
| Code: | | set_tris_a( 0b11100001 ); // set GP1-GP4 to outputs, all other inputs |
GP2-GP3 had to be set to low (not left floating as originally) to let the current flow to the LED.
| Code: | main()
{
init();
output_low( GP2 ); // set low
output_low( GP3 ); // set low
output_low( GP4 ); // set low
while ( TRUE ) // blink LED
{
output_high( GP1 ); // turn LED on
delay_ms( 250 ); // wait 250ms
output_low( GP1 ); // turn LED off
delay_ms( 250 ); // wait 250ms
}
} |
Note that this will blink D7 on the PICKit board. Are you using the PICKit board to test your code or just program, and then run the chip on its own board?
As I think you're doing the later, I would test it first on the PICKit. Now given the fact that you can't blink a non-existent LED on GP0 in the PICKit, you will need to modify this in your board. In theory you would just need the +5V and GND as you pointed (a bypass capacitor is recommended on +5V). You also want a current-limiting resistor (such as R8 on PICKit) between GP0 (or GP1 if you change it) and LED. Make sure LED is installed correctly with anode to GP0 and cathode to GND (hey, it happens sometimes).
As for the Pre-Processor stuff, the help file has a dedicated section for this. The device-file has the possible FUSES.
Hope it helps. |
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brokebit
Joined: 21 May 2004
Posts: 3
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| Posted: Tue May 25, 2004 8:46 pm |
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Languer,
I made the changes but Im still a little confused by the #Fuses pre-processor stuff. I found the following in the help file, however I have not found definitions of the various options, i.e. INTRC_IO, NOCPD, etc:
| Code: | Syntax:
#fuse options
Elements:
options vary depending on the device. A list of all valid options has been put at the top of each devices .h file in a comment for reference. The PCW device edit utility can modify a particular devices fuses. The PCW pull down menu VIEW | Valid fuses will show all fuses with their descriptions.
Some common options are:
· LP, XT, HS, RC
· WDT, NOWDT
· PROTECT, NOPROTECT
· PUT, NOPUT (Power Up Timer)
· BROWNOUT, NOBROWNOUT
Purpose:
This directive defines what fuses should be set in the part when it is programmed. This directive does not affect the compilation; however, the information is put in the output files. If the fuses need to be in Parallax format, add a PAR option. SWAP has the special function of swapping (from the Microchip standard) the high and low BYTES of non-program data in the Hex file. This is required for some device programmers.
Examples:
#fuses HS,NOWDT
Example Files:
ex_sqw.c
Also See:
None
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Thanks
Eric. |
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brokebit
Joined: 21 May 2004
Posts: 3
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| Re: Clock? |
| Posted: Tue May 25, 2004 8:46 pm |
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| Stuck in Fujisawa wrote: | | What is your clock? 400 kHZ, or should it really be 4 MHz? Just a thought... |
Why is your subject Stuck in Fujisawa? |
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languer
Joined: 09 Jan 2004
Posts: 144
Location: USA
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| Posted: Wed May 26, 2004 1:29 pm |
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Eric,
The following #FUSES are found in the device file 12F675.h under the DEVICES subdirectory.
| Code: | // Program memory: 1024x14 Data RAM: 64 Stack: 8
// I/O: 6 Analog Pins: 4
// Data EEPROM: 128
// C Scratch area: 20 ID Location: 2000
// Oscilator Calibration Address: 90
// Fuses: LP,XT,INTRC,HS,NOWDT,WDT,CPD,NOCPD,PROTECT,NOPROTECT,NOMCLR
// Fuses: MCLR,PUT,NOPUT,RC,EC,RC_IO,INTRC_IO,BROWNOUT,NOBROWNOUT |
Each device has their own set of associated FUSES. The FUSES are not defined, but they should have a one-one relationship with the datasheet (section 9.1 for the PIC12F629/675).
One more thing, I just realized that on the new device files the BANDGAP configuration was removed.
| Code: | | /// Fuses: BANDGAPLOW,BANDGAPHIGH |
For good reason probably as these are factory set.
Hope this helps,
languer. |
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