Smaller memory EEPROMS
Philldapill
Posts: 1,283
Just curious if other eeproms can be used, besides the 24LC256? How about the 24LC128 since these are a little cheaper... I'm sourcing parts for a high volume product using the propeller and the standard eeprom, but I want to keep costs to a bare minimum. Can these chips be used?
Comments
-Phil
-Phil
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Beau Schwabe
IC Layout Engineer
Parallax, Inc.
I am not sure how but in the past when I order parts from MicroChip direct, they come from Thailand, but I get them faster than I get parts from mouser, Digikey, or newark using UPS. Usually I get them in 3 days. On the west coast.
Dont be hesitant to order direct from microchip. In my experience they are quite fast in shipping even though they come from Thailand, and the shipping was no more than a distributor cost for UPS ground.
TJ
Short of preprogramming the EEPROM, the .eeprom file could be massaged by copying the first half to the second half. Then it would upload and program okay -- I think.
I was also concerned about stack initialization, since that will be in upper memory and won't receive the usual zero initialization. OTOH, it's a stack and shouldn't need initializing. Non-zeroed extended variable and video buffer space may be a problem, though, so a zeroing phase would have to be performed upon startup (being careful not to encroach upon an already-growing stack). The way to do this would be to zero every long in upper RAM that has a non-zero counterpart in lower RAM.
If the Prop performs a checksum upon reading EEPROM, the duped image shouldn't cause a problem, since both halves will sum to zero anyway.
But all in all, it's too messy just to save a few pennies, IMO.
-Phil