General discussion about add on memory

jet_pack234 · Joined: 11 Feb 2005 Posts: 11

Hi,

Can anyone tell me if it is possible to add additional memory chips to say a mid range PIC such as the 16F628? What if you wanted an enormous look up table or something, or you wanted to store a log of ADC values to do some calculation on.

Also what is the best PIC family money can buy, and what makes it better than the mid range pics? Is it the functions it comes with or the amount of IO it offers?

I cant belive how much fun you have with a PIC that costs £3.50!!

libor · Joined: 14 Dec 2004 Posts: 288 Location: Hungary

I would suggest using a PIC with a built in I2C bus, you can then use the following I2C devices:
- EEPROMs (non-volatile, slow write, limited write-cycles)
- SRAM (volatile, but unlimited write-cycles, fast write)
- MMC cards, SD cards (huge data, cheap, small, replaceable)
etc.

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

With CCS, you don't need a PIC that has a hardware i2c module.
The compiler will generate code for software i2c. So you can
use i2c devices with the 16F628, with no problem.

ckielstra · Joined: 18 Mar 2004 Posts: 3680 Location: The Netherlands

I like FRAM: Similar to EEPROM, but much faster and unlimited re-write times. Only negative issue is the currently maximum size of 256kbit.

For the huge data storages I prefer MMC flash cards, accessable through a serial SPI-bus. Cheap and future proof with new capacities comming out every year. Just be aware that these require writing data in 512 byte blocks, so your PIC need at least 1 kb of internal RAM.