Propeller Proto Boards and using upper 32KB of AT256 EEPROM for storing data.

JamesRonald · 2010-04-10 19:06

So I was looking at at my Propeller Proto Board the other day and I noticed that it has an AT256 EEPROM (64KB) like it says in it products description. Interestingly, the schematic shows a 128Kbit part. Anyway, my question is can the upper 32KB ( > $8000) be used for storing data? I wonder why there is not more discussion on doing such.

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James Ronald
My Robots

Post Edited (JamesRonald) : 4/11/2010 2:26:43 AM GMT

Leon · 2010-04-10 19:29

It can be used, and there has been some discussion of it.

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Leon Heller
Amateur radio callsign: G1HSM

hover1 · 2010-04-10 19:49

Did you mean AT512 (64x8)? That's what on all my Proto Boards.

You can use all of the 32K above the original 32K. There has been much discussion, but searches are not working in the forum right now. I'll see if I can track down some threads.

Jim

Good catch on the schematic. Don't know if it's a documentation error, or they had another part in mind.

Leon · 2010-04-10 20:32

This code shows how to do it:


CON
  _clkmode      = xtal1 + pll16x
  _xinfreq      = 5_000_000
  _stack        = 50
    
  i2cSCL        = 28
'  i2cSDA        = 29 



  EEPROMAddr    = %10101000

  ' EEPROM data base address - i.e 32K (assumes a 64kb eeprom installed!!)
  EEPROM_Base     = $8000
  
  ' debug - USE onboard pins
  pcDebugRX       = 31
  pcDebugTX       = 30

  ' serial baud rates  
  pcDebugBaud     = 115200

    
VAR
  long  i2cAddress, i2cSlaveCounter

OBJ
  i2cObject      : "basic_i2c_driver"

  debug          : "Debug_PC"

  
pub Start
    ' start the PC debug object
    debug.startx(pcDebugRX,pcDebugTX,pcDebugBaud)
  
    ' setup i2cobject
    i2cObject.Initialize(i2cSCL)

    ' pause 5 seconds
    repeat 10
        debug.putc(".")
        waitcnt((clkfreq/2)+cnt)
    debug.putc(13)
  
    ' i2c state
    debug.strln(string("Logger program (v1.0)"))

    ' demo the EEPROM
        if i2cObject.devicePresent(i2cSCL,eepromAddr) == true
            debug.strln(string("EEPROM Present"))
            EEPROM_Demo
        else
            debug.strln(string("EEPROM Missing"))    
        waitcnt(clkfreq*3+cnt)

        


PRI EEPROM_Demo | eepromData, eepromLocation, ackbit
    ' demo the i2c Serial EEPROM (Microchip's 24LC512 (64kb))
    debug.strln(string("EEPROM DEMO"))
      
    ' ***** EEPROM read/Write example *****
    eepromLocation := EEPROM_Base
    eepromData := 0
    
    repeat 10
        ' write long
        eepromData += 100
        i2cObject.WriteLong(i2cSCL, EEPROMAddr, eepromLocation, eepromData)

        ' read long
        eepromData :=0
        eepromData := i2cObject.ReadLong(i2cSCL, EEPROMAddr, eepromLocation)                

        ' debug
        debug.str(string("Read Location="))
        debug.decx(eepromLocation,5)
        debug.str(string(", data="))
        debug.decx(eepromData,5)
        debug.putc(13)        
        
        ' next    
        eepromLocation +=4

        ' slowit
        waitcnt(clkfreq/2 + cnt)

    ' done
    debug.strln(string("EEPROM demo done."))

It uses other code from the Obex.

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Leon Heller
Amateur radio callsign: G1HSM

Post Edited (Leon) : 4/10/2010 8:47:56 PM GMT

JamesRonald · 2010-04-11 02:42

What a pleasant surprise.

I have been watching the propeller and robotics forums for a couple years now and do not remember this topic coming up.

Thanks for the help.

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James Ronald
My Robots

Leon · 2010-04-11 07:10

I'm not sure where that code came from originally. It was probably in the Obex. I think it worked OK when I tried it.

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Leon Heller
Amateur radio callsign: G1HSM

Cluso99 · 2010-04-11 10:23

IIRC mctrivia has some code in the OBEX that uses the upper eeprom.
Here is another in the OBEX that stores and retrieves data from eeprom. I am unsure if this just accesses 32KB but it could no doubt be modified. http://obex.parallax.com/objects/493/

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caskaz · 2010-04-24 12:53

Hi.

I tried above code.
But not operate. (all data are FFFFF)

I checked ProtoBoard(AT24C512)
I modify to EEPROMAddr := %10100000).
I comment out " if i2cObject.devicePresent(i2cSCL,eepromAddr) == true", because there is no method "devicePresent" in object"basic_i2c_driver"

Why cannot data read?

train nut · 2010-04-24 13:46

I have been using the object "bs2_functions" from the objext exchange and it works wonderful for writing to the upper 32K of a 24c512 EEPROM. Use methods Read_Highmem and Write_Highmem to write and read to EEPROM. Hope this helps.

Ben

caskaz · 2010-04-25 00:40

Thanks, train nut.
I modified below.
It fine works.

    eepromLocation := 0
    eepromData := 0
    
    repeat 10
        ' write long
        eepromData += 100
        'i2cObject.WriteLong(i2cSCL, EEPROMAddr, eepromLocation, eepromData)
        BS2.Write_HighMem(eepromLocation, eepromData, 4)

        ' read long
        eepromData := 0
        'eepromData := i2cObject.ReadLong(i2cSCL, EEPROMAddr, eepromLocation)   
        eepromData := BS2.Read_HighMem(eepromLocation, 4)

Why doesn't i2cObject.WriteLong/i2cObject.ReadLong work?
I don't understand reason although reading basic_i2c_driver.

Propeller Proto Boards and using upper 32KB of AT256 EEPROM for storing data.

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