Using PUT & GET

Vern Roach

Dear Parallax People,

On p.245 of the Stamp Manual in refering to Scratch Pad RAM it says that "...each location is always configured as a byte only."··Can I·do the following? :

····················Value·· VAR·· Byte
··················· PUT 0, Value.LOWBYTE
··················· PUT 1, Value.HIGHBYTE

The Stamp Editor didn't balk when I entered the above lines, but I wanted to be sure.

Vern Roach

·········

Jon Williams

The code you've posted doesn't actually work -- is there a typo and is "value" actually a Word?· PUT and GET are used to put and get bytes to/from the Scratchpad RAM.· With PBASIC 2.5 you can do this:

· PUT 0, Word value

What the compiler does is generate this code for you:

· PUT 0, value.LOWBYTE
· PUT 1, value.HIGHBYTE

You can also PUT/GET multiple values like this:

· PUT 0, status, Word value

For this the compiler would generate:

· PUT 0, status
· PUT 1, value.LOWBYTE
· PUT 2, value.HIGHBYTE

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Jon Williams
Applications Engineer, Parallax

Post Edited (Jon Williams (Parallax)) : 11/15/2005 2:13:33 AM GMT

Vern Roach

Jon,

Thanks for being perceptive - Yes, I did mean "Value VAR Word". And thank you for elaborating on the capabilities of PBASIC 2.5. The ability to use GET & PUT very much like READ & WRITE really takes the restrictions off what might seem like a not-too-large RAM capacity. (To 3rd parties: I'm truly a beginner at this!)

Thanks again
Vern Roach

superoo

Just in case you eventually end up short of code space...

Put 0, value.lowbyte
Put 1, value.highbyte

actually uses less code space than...

Put 0, word value




·

allanlane5

Note the EEPROM only supports about a million writes. During normal 'programming' use, this should last a decade or more. If you write to the same location once every millisecond though, you can wear it out in a week.

This is not a problem exactly, just something to be aware of.

PJAllen

That's something I hadn't thought about -- ScratchpadRAM is actually EEPROM space, then?

-- PJA --

Jon Williams

No, the Scratchpad is RAM. That said, PUT and GET (RAM) are analogous to WRITE and READ (EEPROM).

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Jon Williams
Applications Engineer, Parallax

Jon Williams

PUT and GET have no effect on EEPROM.

allanlane5 said...
Note the EEPROM only supports about a million writes. During normal 'programming' use, this should last a decade or more. If you write to the same location once every millisecond though, you can wear it out in a week.

This is not a problem exactly, just something to be aware of.

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Jon Williams
Applications Engineer, Parallax

Chris Savage

No,

·· The ScratchPad RAM is just that, RAM, and has an unlimited number of write cycles, just as variable space does.

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Chris Savage
Parallax Tech Support
csavage@parallax.com

PJAllen

Thanks, guys -- I can breathe again.

allanlane5

D'oh! Sorry about that folks. "Get" and "Put" are for ScratchPad RAM, which has NO write or read limitations, on the BS2p variants. "Write" and "Read" are for EEPROM, which is on all BS2 variants, and can only be written 1 million times.

I've learned my lesson now. Sorry about any confusion.

Chris Savage

allanlane5 said...
D'oh! Sorry about that folks. "Get" and "Put" are for ScratchPad RAM, which has NO write or read limitations, on the BS2p variants. "Write" and "Read" are for EEPROM, which is on all BS2 variants, and can only be written 1 million times.
I've learned my lesson now. Sorry about any confusion.

Okay Homer,

·· While we're getting technical, the EEPROM write life of the BS1 & BS2 is 10,000,000 (Ten Million) writes.· The BS 2e, BS 2sx, BS 2p, and BS 2pe EEPROM is guaranteed for 100,000 write cycles before it wears out.·

Oooh, a donut!

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Chris Savage
Parallax Tech Support
csavage@parallax.com

HIBITDAC

I'm trying to write 42 to the scratch pad and when I get it back out it's 420 not 42. It does this for every number execpt for 0.
If I put 4 in, I get 4 out. Seems like double digit numbers dont want·to work right.

Temp1 = 42
PUT 1, Temp1
.
.
.
GET 1, Temp1
DEBUG "Temp1=", DEC Temp1

I've tried...

PUT 1,Temp1.LOWBYTE
PUT 1,Temp1.HIGHBYTE

Nothing seems to work.

Edit: Oh yeah I'm using a BS2P40

Post Edited (HIBITDAC) : 11/18/2005 10:31:23 AM GMT

Bruce Bates

HIBITDAC -

You failed to mention how Temp1 is defined, WORD, BYTE, NIB? It's always best to include the whole program when asking for assistance on a question like this.

Regards,

Bruce Bates

HIBITDAC

I would post my program but its spans 5 slots, and jumps all over the place so you would probably get lost.

I've defined as Word...samething, Byte...samething, Nib...samething.

If I...

Temp1 = 38

Put 1 Temp1

Get 1,Temp1

Temp1 = Temp1 / 10

It displays 30, samething with 52 execpt it displays 50. seems like it is adding a zero for no reason.

Post Edited (HIBITDAC) : 11/18/2005 10:41:32 AM GMT

HIBITDAC

NEVERMIND..SUPER STUPID moment.