Store Integer into EPPROM question

[Keith]

I have it in the back of mind that I can only store a numeric value to a maximum of 255 onto an EEPROM Y/N

I want to be able to store a numeric value from between 4000 of up to 6525. The Dark Arts folks (Arduino) can do but I can't follow how it works. is it possible? if so how do I do it?

[Anobium]

In the Help.

https://gcbasic.sourceforge.net/help/_lookup_tables.html

Great Cow BASIC will try automatically detect the type of the table depending on the values in it. Great Cow BASIC can be explicitly instructed to cast the table to a variable type, as follows:

Table TestDataSource as [Byte | Word | Integer | Long ]
    12
    24
    36
    48
    60
    72
End Table

Addresssing the Table Data
Item 0 of a lookup table stores the size of the table. If the ReadTable command attempts to read beyond the end (number of data items) of the table, the value 0 will be returned. For tables with more than 255 elements it is mandatory to use a WORD variable to read the size of the table.

[Ccin E Crout]

If you are trying to store a 'word' into Eeprom you could try this:

Sub PutWEeprom (HiAddr As Byte, EWord As Word)
'Places a Word into two bytes of
'Eeprom, HiAddr is the first Byte
'location in Eeprom, the lower Byte
'is placed into the adjacent byte
'
    Let THi = EWord / 256
    Let TLo = EWord - (THi * 256)

    EpWrite (HiAddr,  THi)
    EpWrite (HiAddr+1,TLo)

End Sub

Sub GetWEeprom (HiAddr As Byte, Out EePromWVal As Word)
'Takes the address of the High Byte and returns
'a Word made from the HiAddr and the adjacent
'byte in Eeprom
'
   'The sequence of this 'Rebuild' appears important.
   'The order of Low byte - High must be maintained.
    EpRead (HiAddr+1, EePromWVal)
    EpRead (HiAddr,   EePromWVal_H)

End Sub

These are called like this:

Dim THi As Byte
Dim TLo As Byte
Dim WordVariable As Word
#Define EePromStartAddress 0' This stores a word variable across two byte locations - next free EeProm location is 2

Other code here...

GetWEeProm(EePromStartAddress,WordVariable)

And:

PutWEeProm(EePromStartAddress,WordVariable)

[Anobium]

@cc

Very nice. May I lift and put into Help? I will attribute the knowledge to yourself.

[Ccin E Crout]

By all means.

If you prefer to use Williams, I won't cry!

[William Roth]

I knocked these up for Terry Platt in another thread a couple a weeks ago. Seem to work ok

Sub EPWriteWord(MemLoc, WordVar as WORD)
     EPWRITE MemLoc,WordVar
     EPWRITE (MemLoc+1), WordVar_H
 End Sub

Sub EPReadWord(MemLoc,WordVar as Word)
    EPREAD(MemLoc,WordVar)
    EPREAD(MemLoc+1),WordVar_H
End Sub

[William Roth]

Cleaned up and added Integers to support negative numbers

Sub EPWriteInteger(IN epMemLoc, IN epINTVar as INTEGER)
   EPWRITE epMemLoc, epINTVar
   EPWRITE (epMemLoc+1), epINTVar_H
End Sub

Sub EPReadInteger(IN epMemLoc, OUT epINTVar as INTEGER)
    EPREAD(epMemLoc, epINTVar)
    EPREAD(epMemLoc+1), epINTVar_H
End sub


Sub EPWriteWord(IN epMemLoc, IN epWordVar as WORD)
   EPWRITE epMemLoc, epWordVar
   EPWRITE (epMemLoc+1), epWordVar_H
End Sub

Sub EPReadWord(IN epMemLoc, OUT epWordVar as Word)
    EPREAD(epMemLoc, epWordVar)
    EPREAD(epMemLoc+1), epWordVar_H
End sub

[Anobium]

A thought, that would need investigation.. or may be you have already, but using the EEAddress rather than epMemLoc could save a variable. Check this idea in the ASM... the compiler may already do the optimisation.

:-|

[William Roth]

I was more focused on how it could be easily done than saving a single byte of memory. But I do think that using "EEAddress" would save that byte.

[William Roth]

Here they all are . Used "EEAddress" to save a variable and a few instructions

// Words
Sub EPWriteWord(IN EEAddress, IN epWordVar as WORD)
   EPWRITE EEAddress, epWordVar
   EPWRITE (EEAddress+1), epWordVar_H
End Sub

Sub EPReadWord(IN EEAddress, OUT epWordVar as Word)
    EPREAD(EEAddress, epWordVar)
    EPREAD(EEAddress+1), epWordVar_H
End sub

 // Integers
Sub EPWriteInteger(IN EEAddress, IN epINTVar as INTEGER)
   EPWRITE EEAddress, epINTVar
   EPWRITE (EEAddress+1), epINTVar_H
End Sub

Sub EPReadInteger(IN EEAddress, OUT epINTVar as INTEGER)
    EPREAD(EEAddress, epINTVar)
    EPREAD(EEAddress+1), epINTVar_H
End sub

  // Longs 
Sub EPWriteLong(IN EEAddress, IN epLongVar as Long)
   EPWRITE(EEAddress, epLongVar)
   EPWRITE(EEAddress+1), epLongVar_H
   EPWRITE(EEAddress+2), epLongVar_U
   EPWRITE(EEAddress+3), epLongVar_E
End Sub

Sub EPReadLong(IN EEAddress, OUT epLongVar as Long)
   EPREAD(EEAddress, epLongVar)
   EPREAD(EEAddress+1), epLongVar_H
   EPREAD(EEAddress+2), epLongVar_U
   EPREAD(EEAddress+3), epLongVar_E
End Sub

Please ....someone test these routines

Bill

[Ccin E Crout]

I'm struggling to see how this saves a Byte. Is 'EEAdress' a system variable?

[William Roth]

Variable "EEAddress" is used with both EPRead and EPWrite, so might as well reuse it here. And a few instructions are saved by not moving data from variable to variable.

The only gotcha that I can see is if code was shuffling data around in EEPROM, like a in nested loop of Reads and Writes. In that rare case it may have been better to have different address variables for reads and writes

[William Roth]

Heads Up!

I forgot that many Chips have more than 256 Bytes of EEPROM. In these cases "EEAddress" must be a Word Variable

William

[Anobium]

Use an overloaded Sub(). That will resolve.

[William Roth]

That implies that the code was written with the intention of placing it in a library where 2 subs with the same name (overloaded) makes sense. These were posted with the intention of a user ( Keith) grabbing one or 2 and placing it in his source code.

[Anobium]

OK.

[Keith]

I have tried using William's initial example but I cannot get it compile

If ENCODER_SW = 0 Then
Wait until ENCODER_SW = 1

    CLS
    ;
   EPWriteWord(eepAddr_0, value as WORD)
   EPWRITE eepAddr_0,value
   EPWRITE (eepAddr_0+1), value_H

       Goto Main
  End if

it tells me :-

Errors have been found:

My Spindle Motor Temp Controller.gcb (270): Error: Array/Function
EPWRITEWORD has not been declared
My Spindle Motor Temp Controller.gcb (270): Error: Syntax Error

putting the EPWRITEWORD in the DIM statements as a Word does nothing for it.

[William Roth]

That is not my code! Not even close. It won't compile because you changed it . I think you may be misunderstanding that I gave you new subroutines to use. Use them exactly as I wrote them (as subroutines).

EPWriteWord is a subroutine that I created (you must copy it into your code). Then you call that subroutine when you want to write a Word to EEPROM. Same goes for all of the others.

Note that each WORD written to EEPROM takes up 2 memory locations. IN the example below the value of 4127 uses Locations 10 and 11.

  ' ----------- Main Code Starts Here ---------

Dim TestWord as WORD

EPWriteWord 10, 4127    '// Write Val of 4127 to EEPROM location 10  
EPReadWord 10, TestWord '// Read it back into a variable

Print TestWord  '// Show the Variable on LCD

End


 '------------ Sub Routines Start Here ------------
 ' ----   DO NOT CHANGE OR MODIFY THESE !  -------

Sub EPWriteWord(IN EEAddress, IN epWordVar as WORD)
    EPWRITE EEAddress, epWordVar
    EPWRITE (EEAddress+1), epWordVar_H
End Sub

Sub EPReadWord(IN EEAddress, OUT epWordVar as Word)
    EPREAD(EEAddress, epWordVar)
    EPREAD(EEAddress+1), epWordVar_H
End sub

[Keith]

Thank you so much William, That has settled my threshold temperature issue, I'm not sure where it is being stored in either the 16F18326 EEPROM or the 256k EEPROM on the i2c Bus.

I have seen a small i2c program which gives me a dump of the EEPROM contents but I don't seem to be able to find it.