Memory IC Identification, (Datasheet Included)

[andrewlapham]

I have a cheap android car radio i bought off Aliexpress and was thinking up upgrading the memory ICs. Inside i found two RS256M16V0DB.

http://szrayson.com/uploadfiles/2020/05/20200519171905651.pdf



Are these chips actually 512mb a piece or are they both 256mb? I'm having trouble understanding the datasheet tbh. the android system says it has 1gb installed but just like the fake android version it claims, is it also reporting a fake amount of ram?



Thanks.

 

[PA0PBZ]

The memory chips are 4Gb (Gigabit) each for a total of 8Gb or 1GB (Gigabyte)

[magic]

Is this some sort of common DDR DRAM?

Then there is no autodetection for those things. Size and other parameters of the memory (internal geometry, timings) are encoded somewhere in the firmware blob of the SoC.

[andrewlapham]

I have firmware on hand for the 2gb version of this device. What was really confusing me is how the memory density is calculated. Its a bit confusing when the phisical ic has 256m printed on it when its obviously a 512mb ic.

[mikerj]

I have firmware on hand for the 2gb version of this device. What was really confusing me is how the memory density is calculated. Its a bit confusing when the phisical ic has 256m printed on it when its obviously a 512mb ic.

RS256M16V0DB.

The 256 relates to the number of words and for this device they are 16 bit words.  When expressed as the number of 8 bit words (i.e. megabytes) the number will be doubled.