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tienchuan
Joined: 25 Aug 2009
Posts: 175
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| Help a code example for read write data eeprom on PIC18F |
 Posted: Sun May 26, 2013 9:00 pm |
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Dear all
I'll try to write and read a byte into internal eeprom on PIC18F4680
The read data result is 00
There are 2 slave function on my project
1. Write eeprom
| Code: |
if (check_link_pc == 1)
{
gettime_ds1307 ();
delay_ms (1) ;
printf ("Run time: %02X:%02X:%02X\r\n", hour, min,sec) ;
delay_ms(10);
//-------------------------------------
write_eeprom(0xF00000,0xaa);
delay_ms(10);
write_eeprom(0xF00005,0xbb);
delay_ms(10);
}
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2. Read eeprom
| Code: |
if (check_restore_pc == 1)
{
printf("Sending....\n");
unsigned int8 temp_a=read_eeprom(0xF00000);
delay_ms(10);
printf("%d",temp_a);
unsigned int8 temp_b=read_eeprom(0xF00005);
delay_ms(10);
printf("%d",temp_b);
check_restore_pc=0;
}
}
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I used CCS C ver 4.140
and further, i want to manager address of eeprom by variable int16 to perform for() function to read data eeprom as fast.
Pls show me way to fix it.
Thanks all.
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Sun May 26, 2013 9:25 pm |
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Download the CCS manual and look
http://www.ccsinfo.com/downloads/ccs_c_manual.pdf
Look at the examples of code on page 62 (page 74 in the Acrobat
reader). Does it show 0xF00000 as the address ? No. It shows
values starting at 0.
Also, where does the manual say you need to add a 10 ms delay
after the write_eeprom() function ? It doesn't say that. |
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tienchuan
Joined: 25 Aug 2009
Posts: 175
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| Posted: Sun May 26, 2013 10:00 pm |
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| PCM programmer wrote: | Download the CCS manual and look
http://www.ccsinfo.com/downloads/ccs_c_manual.pdf
Look at the examples of code on page 62 (page 74 in the Acrobat
reader). Does it show 0xF00000 as the address ? No. It shows
values starting at 0.
Also, where does the manual say you need to add a 10 ms delay
after the write_eeprom() function ? It doesn't say that. |
Thank you.
I change my code following on this example but the result is no change, is still 00.
| Code: |
if (check_link_pc == 1)
{
gettime_ds1307 ();
delay_ms (1);
printf ("Run time: %02X: %2X: %02X\r\n", hour, min, sec) ;
delay_ms (10) ;
write_eeprom (0x0, 0x0A) ;
//delay_ms (10) ;
write_eeprom (0x5, 0x0b) ;
//delay_ms (10) ;
printf ("Saved EEPROM") ;
//----------------------------------------
check_link_pc = 0;
}
//-----------------------------------------------------------------------------------
// GOI LAI DU LIEU KHI MAT KET NOI CHO PC
//-----------------------------------------------------------------------------------
if (check_restore_pc == 1)
{
printf ("Sending....\n") ;
temp_a = read_eeprom (0x0) ;
temp_b = read_eeprom (0x5) ;
//printf (" %d", temp_a) ;
putc(temp_a);
//printf (" %d", temp_b) ;
putc(temp_b);
check_restore_pc = 0;
}
}
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Please show me way to fix it.
Thank you.
_________________
Begin Begin Begin !!! |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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tienchuan
Joined: 25 Aug 2009
Posts: 175
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| Posted: Sun May 26, 2013 10:34 pm |
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thanks PCM
But the result is still 00
The result printf on this terminal screen:
| Code: |
Wrote 0x55 to eeprom address 0
Read 00
Wrote 0xAA to eeprom address 0
Read 00
Done
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_________________
Begin Begin Begin !!! |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Sun May 26, 2013 10:37 pm |
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Are you testing this in real hardware or is this a simulation ?
I just installed vs. 4.140 and ran the program on an 18F4580 (it's in the
same PIC family as an 18F4680) and it worked perfectly. I ran it on
a PicDem2-Plus board (non-Rohs version, red board).
| Quote: |
Start
Wrote 0x55 to eeprom address 0
Read 55
Wrote 0xAA to eeprom address 0
Read AA
Done |
Here is the test program:
| Code: |
#include <18F4580.h>
#fuses HS, NOWDT, NOPROTECT, BROWNOUT, PUT, NOLVP
#use delay(clock = 20M)
#use rs232(baud = 9600, xmit=PIN_C6, rcv = PIN_C7, ERRORS)
//===========================================
void main()
{
printf("Start\n\r\n\r");
write_eeprom(0, 0x55);
printf("Wrote 0x55 to eeprom address 0\n\r");
printf("Read %X\n\r", read_eeprom(0));
printf("\n\r");
write_eeprom(0, 0xAA);
printf("Wrote 0xAA to eeprom address 0\n\r");
printf("Read %X\n\r", read_eeprom(0));
printf("\n\rDone\n\r");
while(1);
} |
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tienchuan
Joined: 25 Aug 2009
Posts: 175
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| Posted: Sun May 26, 2013 11:00 pm |
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Thanks PCM
I tested on real hardware, I think have a problem with eeprom?
I tried replace new pic and result is ok.
Thanks great 
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Ttelmah
Joined: 11 Mar 2010
Posts: 19966
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| Posted: Mon May 27, 2013 5:03 am |
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One obvious comment, is "what sets 'check_link_pc' back to zero"?.
If it remains '1' for any time at all, the EEPROM will be destroyed. Every time you write to the EEPROM cell, you use a 'life'. Since a write takes typically 4mSec, and the cell write life is warranted as 100K cycles, you could potentially kill the EEPROM in just 400 seconds.....
Best Wishes |
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tienchuan
Joined: 25 Aug 2009
Posts: 175
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| Posted: Tue May 28, 2013 6:02 am |
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| Ttelmah wrote: | One obvious comment, is "what sets 'check_link_pc' back to zero"?.
If it remains '1' for any time at all, the EEPROM will be destroyed. Every time you write to the EEPROM cell, you use a 'life'. Since a write takes typically 4mSec, and the cell write life is warranted as 100K cycles, you could potentially kill the EEPROM in just 400 seconds.....
Best Wishes |
Thanks u,Ttelmah
I'm writing a first code to test internal eeprom.
Normal, check_link_pc flag is zero, when it controlled by PC, it set to one.
Main Programme will perform task and clear it, so that I think I only work when PC request,normal it don't work as you think
Thanks u.
_________________
Begin Begin Begin !!! |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19966
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| Posted: Tue May 28, 2013 7:52 am |
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Seriously, that is dangerous. The code doing the writing, should clear the flag as soon as the write is done. Otherwise it only takes a little error, for the EEPROM to be killed. Think about it like having a the return spring on the throttle on your car. When you let go, it closes _itself_.
Best Wishes |
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