View Full Version : Boot-Up Time
05-21-2008, 05:54 AM
An off-topic aside in http://forums.parallax.com/showthread.php?p=727089 from Ken Peterson notes issues regarding the boot-up time as the Propeller copies I2C Eeprom to RAM.
I've been wondering for a while what the situation is going to be for the Propeller II which will have eight times as much RAM to fill - 16 second boot times ?
Also, how is this size Eeprom going to be implemented ?
05-21-2008, 06:13 AM
I would hope that it would just load as much from the eeprom as needed and clear the rest. That is, some size somewhere saying "only this much".
Phil Pilgrim (PhiPi)
05-21-2008, 06:33 AM
By clocking the EEPROM's SCL at the 1MHz maximum, 256K x 8 of RAM should be able to load in under three seconds. The trick is to get close enough to 1MHz, using an RC clock, without going over, under all temperature and manufacturing variations. With the current selection of I2C EEPROMS, it looks like 128K x 8 is the biggest available anyway; so it would take two of them, which could be loaded from in parallel, potentially cutting the load time in half.
05-21-2008, 06:48 AM
Loading only as much as is needed is a partial solution but loading would get slower as size increases and the trick of writing to Eeprom to subsequently pre-load variables on next boot wouldn't work unless all but stack were loaded at booting.