sx internal memory vs fram for a 96 byte array
nick bernard
Posts: 329
hail.
i've come to an xroads in my project and i could use some advice.
my application requires a 96 byte array which are updated roughly 10 times a second.
i dont have much experience with the sx28's bank command but gunther's programming the sx has cleared a few questions.
so i'm left with 2 options:
use the sx's internal ram to store my 96 byte array
or use my fram fm24c64 to store my 96 byte array (High Endurance 1 Trillion Read/Writes )
http://www.ramtron.com/lib/literature/datasheets/FM24C64ds_r3.0.pdf
simple math tells me i can expect 6,307,200,000 writes over 20years. which is much less than 1 trillion.
should i trust my fram to hold up over the decades, or develop a complex bank alorithm to satisfy my array?
rox on
nickb
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engineer, fireman, bowler, father, WoW addict [noparse];)[/noparse]
i've come to an xroads in my project and i could use some advice.
my application requires a 96 byte array which are updated roughly 10 times a second.
i dont have much experience with the sx28's bank command but gunther's programming the sx has cleared a few questions.
so i'm left with 2 options:
use the sx's internal ram to store my 96 byte array
or use my fram fm24c64 to store my 96 byte array (High Endurance 1 Trillion Read/Writes )
http://www.ramtron.com/lib/literature/datasheets/FM24C64ds_r3.0.pdf
simple math tells me i can expect 6,307,200,000 writes over 20years. which is much less than 1 trillion.
should i trust my fram to hold up over the decades, or develop a complex bank alorithm to satisfy my array?
rox on
nickb
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engineer, fireman, bowler, father, WoW addict [noparse];)[/noparse]
Comments
Are you using assembly or SX/B ?
SX28 or SX48 ?
Bean.
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·
sx/b & sx28
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engineer, fireman, bowler, father, WoW addict [noparse];)[/noparse]
With the SX28 you need to do some work. In SX/B you can use the first array to access the elements in the other arrays. The trick is that there are 16 byte gaps inbetween. So Array1(15) is the last element in Array1, and Array1(32) is the FIRST element in Array2. But Array1(16) through Array1(31) cannot be used at all.
Here is some code that use subroutines to access a virtual large array on the SX28.
DEVICE SX28,TURBO,OPTIONX,STACKX,OSCXT1 FREQ 4_000_000 Array1 VAR Byte (16) Array2 VAR Byte (16) Array3 VAR Byte (16) Array4 VAR Byte (16) Array5 VAR Byte (16) Array6 VAR Byte (16) pos VAR Byte temp VAR Byte SetElement SUB 2 ' Position, Value GetElement FUNC 1,1 ' Position (returns Value) PROGRAM START NOSTARTUP START: ' Set all elements FOR pos = 0 TO 95 temp = pos * 2 SetElement pos, temp NEXT ' Read all elements FOR pos = 0 TO 95 temp = GetElement pos NEXT END SetElement: __PARAM3 = __PARAM1 AND $F0 __PARAM3 = __PARAM3 << 1 __PARAM4 = __PARAM1 AND $0F __PARAM3 = __PARAM3 OR __PARAM4 Array1(__PARAM3) = __PARAM2 RETURN GetElement: __PARAM3 = __PARAM1 AND $F0 __PARAM3 = __PARAM3 << 1 __PARAM4 = __PARAM1 AND $0F __PARAM3 = __PARAM3 OR __PARAM4 RETURN Array1(__PARAM3)Bean.
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Cheap used 4-digit LED display with driver IC·www.hc4led.com
Low power SD Data Logger www.sddatalogger.com
SX-Video Display Modules www.sxvm.com
Stuff I'm selling on ebay http://search.ebay.com/_W0QQsassZhittconsultingQQhtZ-1
"People who are willing to trade their freedom for·security deserve neither and will lose both." Benjamin Franklin
Post Edited (Bean (Hitt Consulting)) : 11/28/2006 7:33:01 PM GMT
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engineer, fireman, bowler, father, WoW addict [noparse];)[/noparse]