Using EEPROM to store variables...

[mister_e]

O.k this is why,

with your EEPROM, your address must be a word sized variable, so use

wptbd VAR WORD
wptbd = 10

And with wptbd Symbol = 10 written as is you didn't get any compilation error??

[Tom Gonser]

Argg!! I just cannot get those values to stay in EEPROM through a power cycle!!

Here is what I've done:

18F2525
2 x 24LC512 connected as CHIP1, CHIP2
Chip1 con %10100000 ' address of chip1
Chip2 con %10100010 ' address of chip2
resistors in pace.

My program stores data to these chips, and this works. I can store data, then read it back and what I get is valid data (because it contains a checksum, if anything were wrong, the recieving software program would choke)

THEN, I decided I wanted to store the BAUD setting for download and waypoint transmssion, and a flag called PASSTHRU, and Waypoint on/off -- RIGHT IN THE EXTERNAL EEPROM so that I did not have to keep setting it every time I power up the system.

SO,

My program uses the chips memory as follows:

Chip1 address usage:
0-127 = special setting storage
128 - 63872 - logging data

Chip2 address usage:
0 - 63872 - logging data


In the initialization, I have set the following parameters:

' ------------ memory eeprom storage locations --------------------------------------
ADR_loc var word ' location to store the address
CHP_loc var byte ' will only be 1, 2, 3, 4
D_baud_loc var word ' download baud rate
pass_loc var byte ' the flag for passthru - 1 or 0
wpt_loc var byte ' the flag for waypoints - 1 or 0
W_baud_loc var word ' waypoint baud rate

ADR_loc = 100 ' next usable address
CHP_loc = 102 ' the chip we are on
D_baud_loc = 104 ' the download baud value
pass_loc = 108 ' the flag for passthru
wpt_loc = 110 ' the flag for waypoints
w_baud_loc = 112 ' waypoint baud rate

The values actually STORED in these locations are:

address var word ' current memory address
chipselect var byte ' current chip we are on 1 or 2
passthru var byte ' flag - allows data to pass thru to PC
Set_Wpt var byte ' flag allows waypoint data to be sent
wptBD var word ' baudrate of waypoint- ie 16572, etc.
D_baud var word ' baudrate of download speed for PC

SO, my program should ALWAYS know where to look for the various settings. In fact, I have proven that this works - when the program powers up, it confirms that each of these values is correct.

THEN,

I2Cread DPIN, CPIN, Chip1, wpt_loc, set_wpt ' waypoint flag storage
I2Cread DPIN, CPIN, Chip1, Pass_loc, passthru ' passthru flag storage
I2Cread DPIN, CPIN, Chip1, D_baud_loc, D_baud.byte0 ' baud2
I2Cread DPIN, CPIN, Chip1, D_baud_loc+1, D_baud.byte1 'baud2
I2Cread DPIN, CPIN, Chip1, W_baud_loc, wptbd.byte0 ' store waddress 1
I2Cread DPIN, CPIN, Chip1, W_baud_loc+1, wptbd.byte1 ' store waddress 2
I2Cread DPIN, CPIN, Chip1, ADR_loc, address.byte0' get the address 1
I2Cread DPIN, CPIN, Chip1, ADR_loc+1, address.byte1' get the address 2
I2Cread DPIN, CPIN, Chip1, CHP_loc, Chipselect ' get the chipselect

SO - at this point, you'd expect that my program now knows:

1. WHERE to look for the data, and
2. It has read the values from those locations into variables.

The PROBLEM is this.. This works great AS LONG AS I DON'T RESTART. Once I store data using "I2CWRITE" into these locations, I can reliably get them back whenver I want. If I restart, the values are all messed up.

As an example, I wrote a small program to allow me to query these values on a PC screen anytime to troubleshoot. Here is what I see:

Upon first startup:

PARAMETER MEMLOC
Download baud rate unknown: 0 104
Waypoint baud rate unknown: 5837 112
Unknown Streaming setting: 197 108
Unknown Waypoint Setting: 215 110

Last Memory Address: 0 100
Current Chip: 7 102

SO, it is properly looking in the right place, but seeinig garbage values. Once I tell it to store a set of 'Default' values that the program will recognize, I get this response:

PARAMETER MEMLOC
Download baud rate 9600 104
Waypoint baud rate 4800 112
Data WILL NOT stream to GPS-TEAM 108
Waypoint Output ON 110

Last Memory Address: 128 100
Current Chip: 1 102

This response is CORRECT. The program recognizes values and is reporting what the settings are.

If I power cycle, the old garbage values come back - the exact same ones!!

PARAMETER MEMLOC
Download baud rate unknown: 0 104
Waypoint baud rate unknown: 5837 112
Unknown Streaming setting: 197 108
Unknown Waypoint Setting: 215 110

Last Memory Address: 0 100
Current Chip: 7 102

-- so SOMETHING is writing garbage to my memory when I am not looking. Might it be my setup variables for the 18F2525

ADCON0 = %00110000' turn off - select port AN12 (nothing)
ADCON1 = %00001111' turn portA to digital I/O (same as dec 15)

CMCON = $07 ' turn off
HLVDCON = %00000000 ' turn off
CVRCON = $00000000 ' turn off

SSPCON1 = %11011100 ' supposed to be turning on I2C
SSPCON2 = %01111000 ' supposed to be turning on I2C

INTCON = %11110000 ' TG guess at 2525 interrups for all INT pins
INTCON2= %01110100 ' rising edge of INT0,1,2 RB0,1,2
RCON = %10000000 ' no priority interrups

T1CON = %11000000 'Timer1 1:1 prescale.
T0CON = 1

SOMETHING is writing to Chip1 memory locations when I am not looking, I just can't figure out WHAT.. ALL of my loops start at 128, even if I do NO OTHER MEMORY WRITES during a session, the variables STILL get messed up.

HELP!

Tom

[NavMicroSystems]

Tom,

on my DataLoggers I have 16F876 or 18F252 and 2x 24LC512.

The following code is tested.

could you give it a try and let us know what the result was?

   SCL           var PortC.5        ' I2C Clock 
   SDA           var PortC.4        ' I2C Data 
   ROM0          CON $A0            ' EEPROM 0 Address 
   ADDR          VAR word           ' ROM Location
   MonPort       var PortB.7        ' Monitor Port
   Mode          con 16572          ' 4800 Baud 8N1 for Monitor Port
   
   Test          var byte[21]       ' Test Array
   I2Cdelay      con 10             ' Delay after I2Cwrite

   Temp          var byte

CLEAR

SEROUT2 MonPort,Mode,[13,10,"** MCU started",13,10,13,10]

ADDR=100 

I2CREAD SDA,SCL,ROM0,ADDR,[Temp]

IF Temp="*" THEN GOTO SkipWrite       

I2CWRITE SDA,SCL,ROM0,ADDR,_
         [$2A,$20,$54,$65,$73,$74,$20,$45,$45,$50,$52,$4F,_
          $4D,$20,$2D,$2D,$3E,$20,$4F,$4B,$21]

PAUSE I2Cdelay

SEROUT2 MonPort,Mode,["** EEPROM written",13,10,13,10]

GOTO Loop

SkipWrite:

SEROUT2 MonPort,Mode,["** EEPROM write skipped",13,10,13,10]

I2CREAD SDA,SCL,ROM0,addr,[str test\21]

Loop:
  SEROUT2 MonPort,Mode,[STR Test\21,13,10]
  PAUSE 1000
GOTO Loop

END

[Tom Gonser]

Ralph:

Thanks for the demo code, here is what the result was - pasted from the Hyperterminal window. (I added "writing:" to the string so I could see that it was becuse it was not writing anything that showed up on the screen.)
---------------------------------------------------------------------

** MCU started

** EEPROM written

writing:
writing:
writing:
writing:
writing:
writing:
writing:
writing:
writing:
writing:

--------------------------------------------------------------------------

Here is the code I used:

'--------------------------------------------------------------------------------

'Tom,

'on my DataLoggers I have 16F876 or 18F252 and 2x 24LC512.
'The following code is tested.
'could you give it a try and let us know what the result was?


' -----[ Fuses ]------------------------------------------------
@ __CONFIG _CONFIG1H, _OSC_INTIO67_1H
@ __CONFIG _CONFIG2H, _WDT_ON_2H & _WDTPS_128_2H
@ __CONFIG _CONFIG3H, _PBADEN_OFF_3H & _MCLRE_OFF_3H
@ __CONFIG _CONFIG4L, _LVP_OFF_4L & 0bfh ;_XINST_OFF_4L
'
' -----[ Includes/Defines ]---------------------------------------------------------
include "modedefs.bas" 'include serout defines

OSCCON=%01111000
DEFINE OSC 8
While OSCCON.2=0:Wend


SCL var PortC.5 ' I2C Clock
SDA var PortC.4 ' I2C Data
ROM0 CON $A0 ' EEPROM 0 Address
ADDR VAR word ' ROM Location
MonPort var PortC.6 ' Monitor Port
Mode con 16572 ' 4800 Baud 8N1 for Monitor Port

Test var byte[21] ' Test Array
I2Cdelay con 10 ' Delay after I2Cwrite

Temp var byte

CLEAR

SEROUT2 MonPort,Mode,[13,10,"** MCU started",13,10,13,10]

ADDR=100

I2CREAD SDA,SCL,ROM0,ADDR,[Temp]

IF Temp="*" THEN GOTO SkipWrite

I2CWRITE SDA,SCL,ROM0,ADDR,_
[$2A,$20,$54,$65,$73,$74,$20,$45,$45,$50,$52,$4F,_
$4D,$20,$2D,$2D,$3E,$20,$4F,$4B,$21]

PAUSE I2Cdelay

SEROUT2 MonPort,Mode,["** EEPROM written",13,10,13,10]

GOTO Loop

SkipWrite:

SEROUT2 MonPort,Mode,["** EEPROM write skipped",13,10,13,10]

I2CREAD SDA,SCL,ROM0,addr,[str test\21]

Loop:
SEROUT2 MonPort,Mode,["writing: ", STR Test\21,13,10]
PAUSE 1000
GOTO Loop

END

----------------------------------------------------------------


Is this what you expected?

Tom

[Tom Gonser]

I got to wondering why I was getting nothing in the last build. So I trapped for failures to read and write. I did see that it was just not getting there, so tweaked the port assignments, etc. Here is what I get now:

** MCU started

** EEPROM write skipped

Reading:* Test EEPROM --> OK!
Reading:* Test EEPROM --> OK!
Reading:* Test EEPROM --> OK!
Reading:* Test EEPROM --> OK!
Reading:* Test EEPROM --> OK!

(I added "reading" to it)

The program is as follows:

------------------------------------------------------------------


'--------------------------------------------------------------------------------

'Tom,

'on my DataLoggers I have 16F876 or 18F252 and 2x 24LC512.
'The following code is tested.
'could you give it a try and let us know what the result was?


' -----[ Fuses ]------------------------------------------------
@ __CONFIG _CONFIG1H, _OSC_INTIO67_1H
@ __CONFIG _CONFIG2H, _WDT_ON_2H & _WDTPS_128_2H
@ __CONFIG _CONFIG3H, _PBADEN_OFF_3H & _MCLRE_OFF_3H
@ __CONFIG _CONFIG4L, _LVP_OFF_4L & 0bfh ;_XINST_OFF_4L
'
' -----[ Includes/Defines ]---------------------------------------------------------
include "modedefs.bas" 'include serout defines

OSCCON=%01111000
DEFINE OSC 8
While OSCCON.2=0:Wend

SCL var PortC.3 ' I2C Clock
SDA var PortC.4 ' I2C Data
ROM0 con %10100000 ' address of chip1
ADDR VAR word ' ROM Location
MonPort var PortC.6 ' Monitor Port
Mode con 16572 ' 4800 Baud 8N1 for Monitor Port
Test var byte[21] ' Test Array
I2Cdelay con 10 ' Delay after I2Cwrite

Temp var byte

CLEAR

SEROUT2 MonPort,Mode,[13,10,"** MCU started",13,10,13,10]

ADDR=100

I2CREAD SDA,SCL,ROM0,ADDR,[Temp]

IF Temp="*" THEN GOTO SkipWrite

I2CWRITE SDA,SCL,ROM0,ADDR,_
[$2A,$20,$54,$65,$73,$74,$20,$45,$45,$50,$52,$4F,_
$4D,$20,$2D,$2D,$3E,$20,$4F,$4B,$21],failw

PAUSE I2Cdelay

SEROUT2 MonPort,Mode,["** EEPROM written",13,10,13,10]

GOTO Loop

SkipWrite:

SEROUT2 MonPort,Mode,["** EEPROM write skipped",13,10,13,10]

Loop:
I2CREAD SDA,SCL,ROM0,addr,[str test\21],failr
SEROUT2 MonPort,Mode,["Reading:", STR Test\21,13,10]
PAUSE 1000
GOTO Loop

failr:
serout2 monport, mode,["failure to read",10,13]
return

failw:
serout2 monport, mode,["failure to write",10,13]
return


END

[NavMicroSystems]

So your Hardware is OK.

There must be something wrong with your code.

[Tom Gonser]

Hmm.. I am keeping trying to unravel this -- I have a version of your program, but it won't compile.. Can you tell my why I have a 'bad expression'??? It says the I2Cwrite, I2Cread commands are wrong.. I cannot for the life of me make them compile - defining X as a word, byte, whatever..

TG

'on my DataLoggers I have 16F876 or 18F252 and 2x 24LC512.
'The following code is tested.
'could you give it a try and let us know what the result was?
' -----[ Fuses ]------------------------------------------------
@ __CONFIG _CONFIG1H, _OSC_INTIO67_1H
@ __CONFIG _CONFIG2H, _WDT_ON_2H & _WDTPS_128_2H
@ __CONFIG _CONFIG3H, _PBADEN_OFF_3H & _MCLRE_OFF_3H
@ __CONFIG _CONFIG4L, _LVP_OFF_4L & 0bfh ;_XINST_OFF_4L
'
' -----[ Includes/Defines ]---------------------------------------------------------
include "modedefs.bas" 'include serout defines

OSCCON=%01111000
DEFINE OSC 8
While OSCCON.2=0:Wend

SCL var PortC.3 ' I2C Clock
SDA var PortC.4 ' I2C Data
ROM0 con %10100000 ' address of chip1
ADDR VAR word ' ROM Location
portout var PortC.6
portin var PortC.7
Mode con 16572 ' 4800 Baud 8N1 for Monitor Port
Test var byte[21] ' Test Array
I2Cdelay con 10 ' Delay after I2Cwrite

Temp var byte
X var byte
dta var byte

CLEAR

loop:
SEROUT2 portout,Mode,[13,10,"** MCU started",13,10,13,10]
serout2 portout, mode, ["enter 1 to write data, 2 to read it"]
serin2 portin, mode, [DEC temp]

select case temp
case 1
for X = 0 to 256
I2Cwrite SDA, SCL,ROMO,X,[X],failw
pause 10
next x
case 2
for x = 0 to 256
I2Cread SDA,SCL,ROMO,X,[X],failr
Serout2 portout, mode, ["Address: ",#addr," Data:",#dta]
pause 100
next x
end select

goto loop:

failr:
serout2 portout, mode,["failure to read",10,13]
return

failw:
serout2 portout, mode,["failure to write",10,13]
return


END