I2c write&read

[Gusse]

Hi MInhle,

Below is very simple I2C write and read test script.

<code><font color="#000000">CMCON = 7
TRISA = %11000000
TRISB = %00000000

SDA                 <b>VAR </b>PortA.3
SCL                 <b>VAR </b>PortA.4     
LED                 <b>VAR </b>PortB.0     <font color="#000080"><i>'Indicator LED (change if needed)    

</i></font>I2CDeviceEEprom     <b>VAR BYTE    
</b>I2CAddressEEprom    <b>VAR WORD
</b>TEMP1               <b>VAR BYTE
</b>TEMP2               <b>VAR BYTE

</b>I2CDeviceEEprom=$A0     <font color="#000080"><i>'DeviceID 10100000 = $A0 = %1010 A2=0, A1=0, A0=0 R/W=0

</i></font><b>DEFINE </b>OSC 4
    
Main:
    I2CAddressEEprom = 0
    TEMP1 = 1
    <b>GOSUB </b>Write_I2C
    <b>PAUSE </b>10
    <b>GOSUB </b>Read_I2C
    <b>IF </b>TEMP1 = TEMP2 <b>THEN
            HIGH </b>LED        <font color="#000080"><i>'If OK then 0.5s LED blink
            </i></font><b>PAUSE </b>500
            <b>LOW </b>LED
        <b>ELSE
            HIGH </b>LED        <font color="#000080"><i>'If FAIL then 2s LED blink
            </i></font><b>PAUSE </b>2000
            <b>LOW </b>LED
    <b>ENDIF
    GOTO </b>Main   
    
Write_I2C:
    <b>I2CWRITE </b>SDA, SCL, I2CDeviceEEprom, I2CAddressEEprom,[ TEMP1 ]
    <b>RETURN

</b>Read_I2C:
    <b>I2CREAD </b>SDA, SCL, I2CDeviceEEprom, I2CAddressEEprom,[ TEMP2 ]
    <b>RETURN
    
END
</b></code>

If write and read are successfully executed then LED will blink for 0.5s.
2s LED blink will be an indication of fail.

BR,
-Gusse-

[MINHLE]

hello Gusse,

I copy you program. run ---> the light is solid.,



i tr to put direcly data into EEProm, the out put is whatever,,,

i.e.

i = 0 ; data address
b0 = $2a ; data to be stored

i2cwrite .......... i, [b0]

b0 = 0
i2cread .........i,[b0]

run ----> whatever... output (BONUS ONLY)

i have to replace the EEPROm
thanks for your time

regards,

[Gusse]

Hi,

Sorry, I had one bug there. One pause missing.

<code><font color="#000000">CMCON = 7
TRISA = %11000000
TRISB = %00000000

SDA                 <b>VAR </b>PortA.3
SCL                 <b>VAR </b>PortA.4     
LED                 <b>VAR </b>PortB.0     <font color="#000080"><i>'Indicator LED (change if needed)    

</i></font>I2CDeviceEEprom     <b>VAR BYTE    
</b>I2CAddressEEprom    <b>VAR WORD
</b>TEMP1               <b>VAR BYTE
</b>TEMP2               <b>VAR BYTE

</b>I2CDeviceEEprom=$A0     <font color="#000080"><i>'DeviceID 10100000 = $A0 = %1010 A2=0, A1=0, A0=0 R/W=0

</i></font><b>DEFINE </b>OSC 4
    
Main:
    I2CAddressEEprom = 0
    TEMP1 = 1
    <b>GOSUB </b>Write_I2C
    <b>PAUSE </b>10
    <b>GOSUB </b>Read_I2C
    <b>IF </b>TEMP1 = TEMP2 <b>THEN
            HIGH </b>LED        <font color="#000080"><i>'If OK then 0.5s LED blink
            </i></font><b>PAUSE </b>500
            <b>LOW </b>LED
        <b>ELSE
            HIGH </b>LED        <font color="#000080"><i>'If FAIL then 2s LED blink
            </i></font><b>PAUSE </b>2000
            <b>LOW </b>LED
    <b>ENDIF</b>
    <b>PAUSE </b>1000        <font color="#000080"><i>'PAUSE ADDED</i></font>
    <b>GOTO </b>Main   
    
Write_I2C:
    <b>I2CWRITE </b>SDA, SCL, I2CDeviceEEprom, I2CAddressEEprom,[ TEMP1 ]
    <b>RETURN

</b>Read_I2C:
    <b>I2CREAD </b>SDA, SCL, I2CDeviceEEprom, I2CAddressEEprom,[ TEMP2 ]
    <b>RETURN
    
END
</b></code>

Now it will blink.

BR,
-Gusse-

[MINHLE]

Hello Gusse,

thanks for your help,

the eeprom is wrong. I replace a another one. it is ok now.

and the R_SCL and R_SDA are either 13K or 3,3 k the light intensity and frequency does not change (by naked eyes)

thanks again
Minh le

[MINHLE]

Hello Gusse,
actually it is not necessary to " define OSC 4" it is defined in fuse ("INTCLOUT.."

the 24lc256 it takes only 5ms to write

thanks
regards