large value in external EE

Archiver

In a message dated 7/6/2004 1:33:22 PM Eastern Daylight Time,
basicstampede@y... writes:


> Does anyone have a suggestion on how to store a large number in
> external EE and then retrieve it to a BS2 word variable?

Divide your number by 256, like in:

n = 50000
z = 50000/256

store n as a byte. n will be stored as 80, which is the lower byte of 50000.
store z as a byte - 50000/256 = 195.

When you read them back out, reconstitute by writing

n = n + (z*256)

80 + 49920 = 50000

Sid


[noparse][[/noparse]Non-text portions of this message have been removed]

Archiver

I want to store a large integer number (up to 50,000) in an external
EEPROM such as 24C02C.

My first thought is to use 2 EE bytes. e.g. use location 0 and 1
with 0 holding the lower 8 bits and 1 holding upper 8 bits of my 16
bit data.

But when I retrieve the data, it does not seem correct.

Does anyone have a suggestion on how to store a large number in
external EE and then retrieve it to a BS2 word variable?

Thanks.

Archiver

You have the right idea, the problem must be in your implementation.
Write the LOWBYTE of your value to Address, the HIGHBYTE of your value
to Address + 1. Reading is just a reverse of the process: read the
LOWBYTE of your value from Address, the HIGHBYTE from Address + 1. The
LOWBYTE and HIGHBYTE variable modifiers make the process fairly simple.

-- Jon Williams
-- Applications Engineer, Parallax
-- Dallas Office

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Original Message

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From: basicstampede [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Gd6UoTM5RwwB2y8veluRdHEay9H6omLxyUWaVRJIxL15IeuiCu-egpbhTIKNp8Bq9pxWndiF47DraTRy7p0]basicstampede@y...[/url
Sent: Tuesday, July 06, 2004 12:27 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] large value in external EE


I want to store a large integer number (up to 50,000) in an external
EEPROM such as 24C02C.

My first thought is to use 2 EE bytes. e.g. use location 0 and 1
with 0 holding the lower 8 bits and 1 holding upper 8 bits of my 16
bit data.

But when I retrieve the data, it does not seem correct.

Does anyone have a suggestion on how to store a large number in
external EE and then retrieve it to a BS2 word variable?

Thanks.

Archiver

I have had no trouble using READ and WRITE commands with the stamp.
I do predefine the starting value with an EEPROM statement,
probably not needed but the defaults work for over 50% of the units so less
than half need changing.
Watch your formatters, you may be storing the ASCII code of the digits or
something like that.

KF4HAZ - Lonnie

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From: "basicstampede" <basicstampede@y
> I want to store a large integer number (up to 50,000) in an external
> EEPROM such as 24C02C.
>
> My first thought is to use 2 EE bytes. e.g. use location 0 and 1
> with 0 holding the lower 8 bits and 1 holding upper 8 bits of my 16
> bit data.
>
> But when I retrieve the data, it does not seem correct.
>
> Does anyone have a suggestion on how to store a large number in
> external EE and then retrieve it to a BS2 word variable?
>
> Thanks.