External Eeprom 24LC01B with 16F877 and WDT enabled

[Harrison P]

<font face="Courier New" size=-1>Hello Everyone,

I am having some major troubles with the 24LC01B serial eeprom. I enabled WDT because the program that I am using requires wdt to work correctly. I am using the device driver 2401.c include file. I have changed the

#define EEPROM_SDA PIN_B6
#define EEPROM_SCL PIN_B7

to match my program settings.

Here is my setup:

PCM 3.102

24LC01B:
Pin 1 Floating
Pin 2 Floating
Pin 3 Floating
Pin 4 Gnd
Pin 5 Data - PIC B6 - 10k pullup
Pin 6 Clk - PIC B7
Pin 7 WP - Gnd
Pin 8 Vcc

The PIC will read in random data if I do not have the eeprom inserted in its circuit. With the eeprom the PIC keeps on reseting. I do a restart_wdt(); before the read_ext_eeprom(address).

Any help will be highly appreciated. Sorry if my question is hard to follow. I am 15 and it is hard to think correctly after having the eeprom problem for 2 days.

<blink><marquee>Please Help :(</marquee></blink>

Harrison Pham</font>
___________________________
This message was ported from CCS's old forum
Original Post ID: 144515274

[PCM programmer]

:=I am having some major troubles with the 24LC01B serial eeprom. I enabled WDT because the program that I am using requires wdt to work correctly. I am using the device driver 2401.c include file. I have changed the
:=
:=#define EEPROM_SDA PIN_B6
:=#define EEPROM_SCL PIN_B7
:=
:=to match my program settings.

So that means you are using pins B6 and B7 ?
Are you using an ICD debugger ?
Those pins are used by the ICD.

Also, have you tested your program without the WDT ?
Does it work ?
:=
:=Here is my setup:
:=
:=PCM 3.102
:=
:=24LC01B:
:=Pin 1 Floating
:=Pin 2 Floating
:=Pin 3 Floating
:=Pin 4 Gnd
:=Pin 5 Data - PIC B6 - 10k pullup

I always put a pull-up on the clock pin.
According to the Microchip appnote, it might
not be necessary, but do it anyway, for this test.

:=Pin 6 Clk - PIC B7
:=Pin 7 WP - Gnd
:=Pin 8 Vcc
:=
:=The PIC will read in random data if I do not have the eeprom inserted in its circuit. With the eeprom the PIC keeps on reseting. I do a restart_wdt(); before the read_ext_eeprom(address).

What period are you using for the WDT ?
I suggest that you initially set it to the maximum,
while debugging this problem. Put this line
near the start of your program:

setup_wdt(WDT_2304MS);

Also, the 2401.C file has a "delay_ms(11)" statement.
So I suggest that you add the "restart_wdt" parameter
to your "#use delay()" statement
#use delay(clock=4000000, restart_wdt)

What crystal frequency are you using ?
___________________________
This message was ported from CCS's old forum
Original Post ID: 144515304

[Harrison P]

:=:=I am having some major troubles with the 24LC01B serial eeprom. I enabled WDT because the program that I am using requires wdt to work correctly. I am using the device driver 2401.c include file. I have changed the
:=:=
:=:=#define EEPROM_SDA PIN_B6
:=:=#define EEPROM_SCL PIN_B7
:=:=
:=:=to match my program settings.
:=
:=So that means you are using pins B6 and B7 ?
:=Are you using an ICD debugger ?
:=Those pins are used by the ICD.
:=
I am not using a debugger but I am using a bootloader but those pins are not used.
:=Also, have you tested your program without the WDT ?
:=Does it work ?
:=:=
:=:=Here is my setup:
:=:=
:=:=PCM 3.102
:=:=
:=:=24LC01B:
:=:=Pin 1 Floating
:=:=Pin 2 Floating
:=:=Pin 3 Floating
:=:=Pin 4 Gnd
:=:=Pin 5 Data - PIC B6 - 10k pullup
:=
:=I always put a pull-up on the clock pin.
:=According to the Microchip appnote, it might
:=not be necessary, but do it anyway, for this test.
:=
I will try a pullup on the clk pin also.
:=:=Pin 6 Clk - PIC B7
:=:=Pin 7 WP - Gnd
:=:=Pin 8 Vcc
:=:=
:=:=The PIC will read in random data if I do not have the eeprom inserted in its circuit. With the eeprom the PIC keeps on reseting. I do a restart_wdt(); before the read_ext_eeprom(address).
:=
:=What period are you using for the WDT ?
:=I suggest that you initially set it to the maximum,
:=while debugging this problem. Put this line
:=near the start of your program:
:=
:=setup_wdt(WDT_2304MS);
I have tried that and the PIC waits about 2.5 seconds before the wdt kicks in and restarts the PIC which sounds right.
:=
:=Also, the 2401.C file has a "delay_ms(11)" statement.
:=So I suggest that you add the "restart_wdt" parameter
:=to your "#use delay()" statement
:=#use delay(clock=4000000, restart_wdt)
:=
:=What crystal frequency are you using ?
I am using a 20 mhz crystal.
___________________________
This message was ported from CCS's old forum
Original Post ID: 144515305

[PCM programmer]

If you try those things and it doesn't work, then post
a short, but complete program that demonstrates the problem.

Be sure to post all compiler pre-processor directives.

Also, post what bootloader you are using, and the
power supply voltage that you're using for the PIC
the and eeprom.

___________________________
This message was ported from CCS's old forum
Original Post ID: 144515307