Who’s wrong, RevEd or TechSupplies?
- Thread starter boriz
- Start date
Jeremy Leach
Senior Member
Think it's the difference between Kbytes and Kbits.
The picaxe I2C help file shows 2K as 2 kilobytes, whereas tech supplies say 16 kilobits. 2 kilobytes x8 = 16 kilobits. I think memory sizes are usually labelled in bits rather than bytes. when you're figuring out the number of available bytes a memory has, then rev-ed is correct. They probably didn't say whether they're talking bits or bytes. The value difference means that rev-ed talks bytes, and tech-supplies talk bits.
westaust55
Moderator
Its definitely as follows:
24LC16 = 16K-bits = 2K-bytes
24LC256 = 256K-bits = 32K-bytes
right now Tech Supplies website at your link states:
Microchip 24LC16B/P 16K EEPROM.
and
Microchip 24LC256/P 256K EEPROM.
that is not stating bits or bytes
Manufacturers Microchip state:
"The Microchip Technology Inc. 24AA256/24LC256/24FC256 (24XX256*) is a 32K x 8 (256 Kbit) Serial Electrically Erasable PROM"
and "Density 256K bits (x8)"
So in summary, neither are wrong, its just different ways of expressing the same thing.
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hippy
Ex-Staff (retired)
The last number in a 24LC256 etc is usually the number of kilobits, so for 24LC16 that's 16 kilobits, 2 kilobytes, for 24LC256 that's 256 kilobits, 32 kiliobytes.
That's not always entirly true, eg 24LC1025 is 1024 kilobits, 128 kilobytes.
There is an ambiguity, manufacturers often use "K" for kilobits (Kb), programmers often take "K" as kilobytes (KB), some publishers get their KB and kb confused, and that can happen where descriptions are upper-cased. Best bet is to look at the manufacturer's datasheet.
Two things to also note -
For "MB" sizes of SD Card and the like the M is often million of bytes (1,000,000) not megabytes (1,048,576)
For "kHz" the k should be lower-case
That's not always entirly true, eg 24LC1025 is 1024 kilobits, 128 kilobytes.
There is an ambiguity, manufacturers often use "K" for kilobits (Kb), programmers often take "K" as kilobytes (KB), some publishers get their KB and kb confused, and that can happen where descriptions are upper-cased. Best bet is to look at the manufacturer's datasheet.
Two things to also note -
For "MB" sizes of SD Card and the like the M is often million of bytes (1,000,000) not megabytes (1,048,576)
For "kHz" the k should be lower-case
For those unfamiliar with metric basics, it's crucial to use a lower case 'k' (kilo) when meaning x 1000. Capital 'K' strictly means Kelvin (temperature). Hence a distance should be shown 10km, & NEVER 10KM or 10 Km. Yes- that 'm' means metres & not miles. Astoundingly a US traffic engineer I know considered a 3m road verge as being 3 miles wide!
While we're at it, 'm' (milli = x 1/1000 ) & 'M' (mega = x 1,000,000 ) are often confused with 'µ' (mu), meaning x 1/1,000,000) - you may see this on capacitors. I've helped focus woolly minds in the past by asking if they'd rather have a m$, M$ or µ$.
While we're at it, 'm' (milli = x 1/1000 ) & 'M' (mega = x 1,000,000 ) are often confused with 'µ' (mu), meaning x 1/1,000,000) - you may see this on capacitors. I've helped focus woolly minds in the past by asking if they'd rather have a m$, M$ or µ$.
BeanieBots
Moderator
Nice reminder Manuka.
I've seen mF used instead of uF all too often. Maybe that's why it's customary to write the value of big caps with all the extra 0s eg 10,000uF instead of using 10mF?
Who mentioned Hubble
I've seen mF used instead of uF all too often. Maybe that's why it's customary to write the value of big caps with all the extra 0s eg 10,000uF instead of using 10mF?
Who mentioned Hubble
westaust55
Moderator
Under the SI system, capitals are used where the unit has been named after a person and lower case for units not named after a person.Nice reminder Manuka.
I've seen mF used instead of uF all too often. Maybe that's why it's customary to write the value of big caps with all the extra 0s eg 10,000uF instead of using 10mF?
Who mentioned Hubble
prefixes less than or equal to 1000 are a lower case letter and prefixes greater than 1000 are capitals
so Volts, Amperes, Hertz, Newtons, Farads, Tesla, etc are named after people
metres, grammes, etc are not.
pico (p), nano
, micro (u), milli (m) and kilo (k) get lower case butMillion (M), Billion (B), Tera (T) etc get capitals
EDIT: Hard drive manufacturers are the most renown for calling 1,000,000 bytes a MB whereas the rest of the computing industry calls 1,048,576 bytes a MB.
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