8-bit Microcontrollersのトピック9S08DZ32: Can EEPROM be read during erase/byte program of a different address?

9S08DZ32: Can EEPROM be read during erase/byte program of a different address?

Cantalis — Wed, 23 Sep 2009 03:03:28 GMT

Hello,

I am migrating software from 68HC05X16 to 9S08DZ32. For 68HC05 EEPROM the data sheet says:

"If a read operation is executed while the E1LAT bit is set (erase or programming sequence), data resulting from the operation will be $FF."

In the 9S08DZ data sheet I cannot find a similar statement regarding EEPROM-read while a programming/erase cycle is executed.

Does this mean that I can do the following: (?)

(example)

- I decide to erase EEPROM at address 0x1600

- I issue the "sector erase" command to do so

- While erase is performed (takes appr. 20ms) I decide to read from address 0x1608

(NOT in the same sector as 0x1600)

Will this last step perform correctly (returning the byte stored at 0x1608)?

Thanks for any comments

Best regards

-Roland

Re: 9S08DZ32: Can EEPROM be read during erase/byte program of a different address?

bigmac — Thu, 24 Sep 2009 02:12:56 GMT

Hello Roland,

My understanding is that, for the 9S08DZ device, the EEPROM is a single array, and the whole array cannot be read whilst a sector erase or write is occuring. However the flash memory is a different array from the EEPROM. So the flash memory can be read during EEPROM erase. Similarly, the EEPROM can be read during a flash sector erase.

Regards,

Mac

Re: 9S08DZ32: Can EEPROM be read during erase/byte program of a different address?

Cantalis — Sat, 26 Sep 2009 21:13:13 GMT

Mac,

you write:

>for the 9S08DZ device, the EEPROM is a single array,...

I am not sure if this "single array view" is correct here, because

the data sheet speaks of "8-byte-sectors" that the EEPROM

consists of.

So if the erase/program logic should see the EEPROM as an

arrangement of sectors I think it could be possible that

an erase/program access could leave the other 8-byte-sectors

readable and only address that one specific 8-byte-sector to

do the erase/program operation.

Best regards

-Roland

Re: 9S08DZ32: Can EEPROM be read during erase/byte program of a different address?

peg — Sun, 27 Sep 2009 05:55:58 GMT

Hello Cantalis,

The entire array is taken out of action by the fact that during erase and write operations the programming voltage is applied to the whole array at once.

Please refer to the many other discusssions on this in this forum.