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edbfmi1
Joined: 18 Jul 2006
Posts: 98
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| I2c Using 2416EEprom and 16C57 |
 Posted: Mon Aug 07, 2006 2:35 pm |
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I am trying to write a simple program to store and retrieve a byte of data to address 1 on an 24LC16B EEprom using a PIC16C57. The idea is to write the value 9 to the EEPROM reset value to 0. Then read the the EEPROM to see if the value read is 9. My simple code is below.
I do have pullups on the SDA and SCL lines.
The program gets into a loop when it does the initial write.
I also have a memory problem that I describe after the code listing below.
| Code: | // --------------------- I2C ---------------------------------------
#include <16C57.h>
#device *=8,
#fuses HS,NOWDT,NOPROTECT
#use delay(clock=40000000)
#define EEPROM_SDA PIN_B6
#define EEPROM_SCL PIN_B7
#include <2416.c>
long int address;
byte value;
/* Prototypes */
void main(); /* Main Routine */
void write_eeprom()
{
BYTE value;
EEPROM_ADDRESS address;
init_ext_eeprom();
WRITE_EXT_EEPROM( address, value );
}
void read_eeprom()
{
BYTE value;
EEPROM_ADDRESS address;
init_ext_eeprom();
value = READ_EXT_EEPROM( address );
}
void main()
{
while (1==1)
{
address = 1;
value = 9;
write_eeprom();
value = 0;
read_eeprom();
// value = 8;
// write_eeprom();
// value = 0;
// read_eeprom();
}
} |
I planned on doing this again with the value of 8 but of I unremark the the last four lines I get the following when I compile the simple program:
Error[71] C:\A_TEST\I2C.C 54 : Out of ROM, A segment or the program is too large main
Seg 00000-001FF, 0125 left, need 01ED
0000
Seg 00200-003FF, 0200 left, need 0206
0000
Seg 00400-005FF, 0200 left, need 0206
0000
Seg 00600-007FF, 0200 left, need 0206
0000
Seg 00000-001FF, 0125 left, need 0206
0000
1 Errors, 0 Warnings.
With the last four lines remarked out I get the following when it is compiled:
ROM used: 991 words (48%)
Largest free fragment is 512
RAM used: 25 (35%) at main() level
34 (47%) worst case
Stack: 1 locations
I am not sure why I use up so much memory with 4 commands?
Any input would be greatfully accepted. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Aug 07, 2006 2:52 pm |
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You have set the clock speed to 40 MHz. Max speed allowed is 20 MHz.
This setting must match your crystal value.
This PIC has only 2 stack levels. Sherpa Doug would be the one
with experience in writing CCS code for this type of PIC. |
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rnielsen
Joined: 23 Sep 2003
Posts: 852
Location: Utah
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| Posted: Mon Aug 07, 2006 2:55 pm |
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Your code could be longer than you might expect because it also includes 2416.c. You are declaring 'address' and 'value' as global variables and then RE-declare them as local variables inside read_eeprom() and write_eeprom(). Either use Only the global variables and have each function and main() use them or declare them inside of main() and then pass the variables to each function.
Ronald |
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edbfmi1
Joined: 18 Jul 2006
Posts: 98
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| Posted: Mon Aug 07, 2006 3:05 pm |
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I got a little carried away with the "0" it should have been 4Mhz 
I also made the variables global for this simple program but still no luck 
Thanks for the input. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Aug 07, 2006 3:11 pm |
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| How do you tell if the program is working ? Are you using an ICE ? |
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edbfmi1
Joined: 18 Jul 2006
Posts: 98
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| Posted: Mon Aug 07, 2006 3:20 pm |
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| Yes I am using MPLAB v5.7 with the Picmaster in curcuit emulator to watch the values of the registers. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Aug 07, 2006 3:49 pm |
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Have you run a very simple program (without EEPROM access) so that
you can prove that the ICE is working ? |
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Guest
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| Posted: Mon Aug 07, 2006 4:05 pm |
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Yes,
I have used the ICE to debug a portion of the program that this will be incorporated with. The program multiplexes a 4 digit 7-segment display. All works fine with that part of the program. I removed it for simplicty while I write the next part of the program that stores the data displayed in the EEPROM. I just re-ran the display program again to verify the ICE is working and it worked fine. |
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edbfmi1
Joined: 18 Jul 2006
Posts: 98
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| Posted: Mon Aug 07, 2006 4:08 pm |
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OOPs,
The "guest" reply above was from me. I just got on line at home and forgot to log in before I replied. |
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