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Topic: spi 9bit eeprom address can only see addr 0x00? (Read 5860 times) previous topic - next topic


Pinout looks good - you have decoupling on the chip?  You need it.  Keep the SPI wiring short and bundled
together with the ground/supply wires for good measure.

Also when talking to a new SPI chip like this the first thing to do is read the any status registers and
see if the bits coming out make sense.  Once thats working you have confidence the basic comms
is functioning - one step at a time is how things are made to work...  Be methodical and check everything
twice - its surprising how often that fixes things.

Then for a memory chip implement READ - the inital values for EEPROMs are usually all 0xFF, check
its returning what is expected.

Then implement WRITE - if you think you've got write working on address 0, write a 0xAA (or any unique
pattern you will recognise) and read back all the memory - this will tell you for sure what's working.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]


leads are about 3 inches, tried everything you said, its only writing the first value (using a for loop to write a few different values) and reading that value back no matter how many address' i cycle through. i really appreciate you guys trying to decipher this but maybe ill order some i2c 256kbit eeproms and just nix the cpu supervisor all together, too bad PaulS or Nick Gammon wont comment i bet you they can figure it out in about 10 seconds  ;)

you know if it wasnt for Nick Gammon's website alot of my projects wouldnt be, he answers just about everything ive ever wondered how to do with my arduino. thanks Nick for sharing the knowledge. today im dumping a bootloader on a blank atmega328p using Mr. Gammon's method/sketch. http://www.gammon.com.au/forum/?id=11635

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