what is the reason? -93lc66 EEPROM write problem- PIC16f877

[optech]

93c66

I am trying to write to 93lc66 eeprom with PIC16F877. I succeded this for atmel's DIP 93c66. But I want to do that for microchip's SMD 93lc66. I can't do that for microchip's eeprom. Why? What is differences?

Thanks..

 

[optech]

93lc66 EEPROM write problem

For somebodies, this question would be very simple. But now, for me this is important. In end of my project, as I think I complated the project, this problem has been appeared. I am in very hard times. Please help me!

Thanks...

 

[IanP]

Re: what is the reason? -93lc66 EEPROM write problem- PIC16f

Compare your code with the one from this Microchip's application note: https://ww1.microchip.com/downloads/en/AppNotes/00560.pdf
and carefully look for a nuance in, for example, timing..in the write/read routines..
Unfortunatelly, it is not alweays true that if you have working code that works with one EEProm, it doesn't mean that it will be 100% OK with one frome another manufacturer, although in theory it should..
Regards,
IanP

 

[optech]

Re: what is the reason? -93lc66 EEPROM write problem- PIC16f

Thanks for your reply. I have tried the codes in this application note. In 16bit mode, data has been wrote to EEPROM correctly.
I am comparing this codes with mine. My codes for 8 bit. First, I had a suspicion about this EEPROM support which mode. I tested the eeprom in 8 bit and 16 bit modes with a programmer to see which modes supported for EEPROM. I saw both modes supported for EEPROM.
Then, I had another suspicion about time flowing differences between my codes and the codes that in this application note. I changed some small differances. After that, the flows be same.But it didn't work. Then I think, write time delay not enough in my codes. I make it up(10ms). But It didn't work again. I think, the times between CLK and DI datas are not enough. I changed it. I didn't work.

Shotly, It DOES NOT WORK now. I will try a few think. The situation is here. But, I am sure, I will success...

Thanks for your replay again.

 

[XNOX_Rambo]

Re: what is the reason? -93lc66 EEPROM write problem- PIC16f

How have you connected pins 6 and 7?
What is your supply voltage?

 

[IanP]

Re: what is the reason? -93lc66 EEPROM write problem- PIC16f

In some cases if you select 8-bit mode the EEProm may behave very funny: the 8-bit data will be written to two consecutive location, say, 00 and 01, 02 and 03 and so on, and there is bloody nothing you can do about it. If it is the same story in your case, just write and read every second location, so, instead of having 4kB memory you will end up with a 2kB one..
Regards,
IanP

 

[optech]

Re: what is the reason? -93lc66 EEPROM write problem- PIC16f

@XNOX_Rambo

I connected pin 6 (ORG) to GND. Pın 7 is NC(not connected). Supply voltage is 9v and cirsuit has a regulator(7805) to regulate voltage to 5V. That is, eeprom's Vcc pin connected to 5V.


@IanP

I can't write anythink. So, there is nothing to read. I tried all things that I know. It don't work for 8 bit. I have to do it for 8 bit.


Now I will show you timing diagrams in app note and mine.

Please look it. Please look out those: mine is 8bit and executing more short time. In app note, 16bit and time is more long.

 

[IanP]

Re: what is the reason? -93lc66 EEPROM write problem- PIC16f

You are one bit short in the address section: you should have 1(start)+2(op)+9(address)=12
From picture you sent you have only 11, for 8-bit configuration, that is. The application note timinig is for 16-bit configuration, and therefore they show 11 bits for the address section.
Regards,
IanP

 

[optech]

Re: what is the reason? -93lc66 EEPROM write problem- PIC16f

Thank you,

I send the datas like this: SB(Start Bit) + OPCode + Adress(A8-A0) + DATA(8bit)

But only for EWEN command, I forgot a clock. If you look the adress which send after EWEN command, you will see that.

I changed this and solved my problem, thanks for your helps...

See you....

 

[atferrari]

If I recall properly...

In my project, years ago, only those from Microchip worked OK. There was a warning in Microchip's datsheet about that.

Myself I found that from other sources, didn't work.

Just in case check it, but I think it was that memory.

Agustín Tomás