maemo.org - Talk - Commands on EEPROM

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Commands on EEPROM

So, I found this in my mailbox today:

http://i43.tinypic.com/2qu3rjc.jpg

An AT24C02 EEPROM with a wopping 256 bytes of data :p

Since EEPROMS are very very easy to program, this is a very quick way to make your custom OH instantly very awesome!

But, since I am an extreme hardware guy (and a little low on software knowlegde), what to put on them??

Howto:
-download a picture and set it as ambiance?
-download and install a program?
-change settings?
-start a daemon?

Also, they are dirt-cheap.

Re: Commands on EEPROM

Also, GITHUB has this page

Quote:

struct toh_eeprom_entry toh_eeprom[] = {
{ TOH_EEPROM_VENDOR, 2, 0 },
{ TOH_EEPROM_PRODUCT, 2, 2 },
{ TOH_EEPROM_REV, 1, 4 },
{ TOH_EEPROM_EEPROM_SIZE, 2, 5 },
{ TOH_EEPROM_CFG_ADDR, 2, 7 },
{ TOH_EEPROM_CFG_SIZE, 2, 9 },
{ TOH_EEPROM_UDATA_ADDR, 2, 11 },
{ TOH_EEPROM_UDATA_SIZE, 2, 13 },
};

Re: Commands on EEPROM

Well, 256 bytes don't hold very impressive images or sounds. that's for sure :D

I'd imagine what you can put there is an URL that gets downloaded by the system when you insert the EEPROM, for example. Now you'd need to write up a daemon that gets kicked when an EEPROM of the signature you have gets inserted to I2C...

Re: Commands on EEPROM

Quote:

Originally Posted by dirkvl (Post 1406236)

An AT24C02 EEPROM with a wopping 256 bytes of data :p

Since EEPROMS are very very easy to program, this is a very quick way to make your custom OH instantly very awesome!

256 bytes is about same capacity of the NFC tags. If it's just to recognize the OH wouldn't be better to use those (and spare the energy to power the EEPROM) ?
Otherwise, how does read/write cycles in NFS tags and EEPROMs compare, when they are used to periodically store temporary data?

Re: Commands on EEPROM

Remember that the VDD in toh is 3.3V, and I2C levels are 1.8V CMOS, so the EEPROM might not talk with you.

Re: Commands on EEPROM

Quote:

Originally Posted by juiceme (Post 1406281)

Well, 256 bytes don't hold very impressive images or sounds. that's for sure :D

Well no, that's why I said 'download' image :p Although there are also a lot bigger EEPROMS, I think its power is in simple commands.

Quote:

Originally Posted by minimos (Post 1406286)

how does read/write cycles in NFS tags and EEPROMs compare, when they are used to periodically store temporary data?

Stand-by current of eeprom = 8 micro-amps. Read/write is a bit higher, but write time is a few milliseconds. The thing is, EEPROMs are available and Jolla NFCtags are not. Also, when you are making a PCB for an OH, it is way easier to also put an EEPROM on there instead of also making an NFC tag.

Quote:

Originally Posted by kimmoli (Post 1406298)

Remember that the VDD in toh is 3.3V, and I2C levels are 1.8V CMOS, so the EEPROM might not talk with you.

I believe EEPROMS are designed with flexibility in mind, so I think this will be okay!

Quote:

Originally Posted by juiceme (Post 1406281)

Now you'd need to write up a daemon that gets kicked when an EEPROM of the signature you have gets inserted to I2C...

Ha! See this post. Thats the beauty, the phone automatically looks for it.

Anyway, the question was not 'if' but 'how'! What kind of commands could you put on there?

Re: Commands on EEPROM

Quote:

Originally Posted by dirkvl (Post 1406314)

I believe EEPROMS are designed with flexibility in mind, so I think this will be okay!

you wish... with I2C, anything is possible, it is "standard", but implementations varies.

VinHIlow = VCCx0.7V (aka CMOS) and when VCC is 3.3V, means that SDA/SCL needs to be ~2.3V to make sure them to be high.
(Ref AT24C02 datasheet)

Re: Commands on EEPROM

Okay, then i put an regulator in between that outputs 2 volt to the Vcc of the EEPROM, problem solved. At least for trial fase.

Re: Commands on EEPROM

In recent developments, the qwerty-oh is upgraded with a 1.8V voltage regulator, which mean I will very probably also stick an EEPROM on there.

Has anyone -by chance- come by some EEPROM commands for Sailfish?

Re: Commands on EEPROM

Quote:

Originally Posted by dirkvl (Post 1407716)

you'll need to create that interface yourself :)
An eeprom is programmed by electric signals on designated addressbusses and will output whatever you put in their. Those instructions can then be used by microcontrollers, or TOH, interpreting the output.

http://www.engineersgarage.com/elect...s/24c02-eeprom