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Stm32f103T8C6 and 93C66 EEPROM

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Junior Member level 3
Jun 8, 2010
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Hi all,

being new with stm32 and all of it I would need little help on that matter.

I got Stm32f103T8C6 board and 93C66 EEPROM.
I would like to store some of my info on that eeprom.

From reading stm datasheet it seems that stm is 8bit oriented, so everything is done in multiples of 8 (is that correct).
Second, 93C66 says that for instructing it how to behave (read/write/erase....) I have to do opcodes in form of:
1 start bit
XY opcode
A9-A0 address

So if my stm works in multiple of 8 does it mean It cannot work with 93C66.

Also from doc:

The Read Data from Memory (READ) instruction
outputs data on Serial Data Output (Q). When the
instruction is received, the op-code and address
are decoded, and the data from the memory is
transferred to an output shift register. A dummy 0
bit is output first, followed by the 8-bit byte or 16-
bit word, with the most significant bit first

If it first outputs dummy 0 and then 8 bit value .... that is 9 digits and I am 8 bit oriented, so again??:bang:

Here is the datasheet for eeprom

Could someone please clear it out??
Thanks in advance.


When I read this, one important information is missing: what interface are you talking about.

So looking for datasheet, downloading, reading..

..microwire... I never used it. Has the ST built in microwire interface?
It seems to me the 8 bit and 16 bit given in the datasheet is internal organisation instead of interface bit count.
Both devices are from microchip, so (if st has microwire interface) I expect there should be application notes and code samples.
I often use SPI EEPROM like 25xx040. With SPI it is very common, that the interface transfer is in multiples of 8 bit.


- - - Updated - - -


Now I recognised the datasheet link, sorry for complaining ...

Jameco seems to be the distributor, ST is the manufacturer.


So if my stm works in multiple of 8 does it mean It cannot work with 93C66.
As far as I understand, you are asking if a 93C66 EEPROM can be interfaced with a hardwire SPI master.

It should be possible utilizing the start bit in 93C66 command word, filling the sequence with leading zeros to a multiple of 8-bits. But I must admit that I always used bit banging for 93Cx6 interface on any microprocessor. So I never tried.

You probably find many 93Cx6 code examples using bit-banging, there should be no problem to port it to stm32.

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