18F1320 ... Strange Memory

[Acetronics2]

Hi,Luciano

I have 05250SE as a code.

I bought them at the end of last year ( 2005 ) from FARNELL.

I've seen the errata giving an increasing EEPROM Writing time from 4 to 5.5 ms ...

may be, MPLAB didn't follow ...

something strange is I have to program it in 4 times ( ! ) to get 100% success

1) Erase all
2) Config words only( Ok only at second pass ...)
3) Program only
4) EEPROM only

setting to "Auto select" fails at each trail ... " Erase all at first" too

Alain

[mister_e]

Maybe MPASM don't follow or just consider the newer device... I'll not be surprise if so...

Let's see what Melanie will discover with her brand new version.

[Dave]

Acetronics, Last year I worked on a project for almost 4 months trying to get an 18F1320 to operate @ 40 Mhz. and then @ 20 Mhz. with eratic results. After looking at the data sheet I decided to use the 16F88 and have never gone back to the 18F1320. The errata sheets tell all. I ordered parts from DigiKey and they said that they had the latest hardware on hand but after receiving 50 parts of an old revision I gave up ordering from them. I was on the MicroChip forum for about 2 months and found out that they wern't very stable as far as the PLL goes and very sensitive to power supply variations. Like I said after looking at the data sheets of the 2 I decided to go with the 16F88 and haven't looked back yet. LOL

Dave Purola,
N8NTA

[Luciano]

Alain,

The oscillator speed of your PIC is 20MHz.

Can you try to change "DEFINE OSC 20" in "DEFINE OSC 25" and flash
the PIC running at 20 MHz with this code? If you try that you will
probably increase the EEPROM writing time and see if ONE write is
enough. This is just a test.

Best regards,

Luciano

EDIT:
Are you absolutely sure that the oscillator speed is correct?

-

[Acetronics2]

Alain,

The oscillator speed of your PIC is 20MHz.

Can you try to change "DEFINE OSC 20" in "DEFINE OSC 25" and flash
the PIC running at 20 MHz with this code? If you try that you will
probably increase the EEPROM writing time and see if ONE write is
enough. This is just a test.

Best regards,

Luciano

EDIT:
Are you absolutely sure that the oscillator speed is correct?

-

Hi,Luciano

Sorry, but that won't give anything ... as the EEPROM writing time is controlled by the PIC Hardware ...

For the Osc speed, it's correct : 1.52 ms input signals give ( 279 + 7H ) Hex.

( EEPROM addresses are: 01 high byte, 02 low byte, and 30 Offset )

Thanks for the idea ...

Alain

[Luciano]

Alain,

I understand that at completion of the write cycle, the WR
bit is cleared in hardware and the EEPROM Interrupt Flag bit
(EEIF) is set. The user may either enable this interrupt
or poll the WR bit. There is also a third barbarous method which
is just wait 10 ms.

In your post you say that PbP uses the polling method. This
should be ok if the microcontroller hardware has no bug.

Can you put a "PAUSE 10" after each WRITE in your code?
(10 ms pause).

Best regards,

Luciano

[Acetronics2]

Sorry one more time, Luciano ... the problem only occurs with a single writing !!!

a Pause won't change anything ... and won't change the EEPROM writing time.

Alain