How to read & write to a 25aa1024 (1 Mbit SPI Bus Serial EEPROM) via 16F88

[mackrackit]

I picked up a couple of these 24FC1025 and I am not having any luck either.

A0 and A1 and WP are connected to VSS.
A2 connected to VDD.
10K pull up on SDA and SCL.
Tried "start/stop" sequence before and after I2C commands...

Out put to terminal is 0 no matter what.

'  18F6680  24FC1025
    DEFINE OSC 20
    @ __CONFIG    _CONFIG1H, _OSC_HS_1H
    @ __CONFIG    _CONFIG2H, _WDT_OFF_2H & _WDTPS_128_2H
    @ __CONFIG    _CONFIG4L, _LVP_OFF_4L
    
    TRISF = 0
    PORTF = 0
    DEFINE I2C_SLOW 1
    DEFINE I2C_SCLOUT 1
    DPIN    VAR PORTF.6    'I2C DATA PIN
    CPIN    VAR PORTF.7    'I2C CLOCK PIN
    CONTR   CON %10100001  'READ CONTROL
    CONTW   CON %10100000  'WRITE CONTROL
    ADDR    VAR WORD
    DATI    VAR BYTE
    DATO    VAR BYTE
    ADDR = %0000000000000000
    DATO = %11110000
    
    START:
    SEROUT2 PORTB.2, 16572,["TEST",$d,$a]
    PAUSE 1000
    
    HIGH CPIN:HIGH DPIN:LOW DPIN
    I2CWRITE DPIN,CPIN,CONTW,ADDR,[DATO]  
    HIGH CPIN:LOW DPIN:HIGH DPIN
    Pause 10                

    HIGH CPIN:HIGH DPIN:LOW DPIN
    I2CREAD DPIN,CPIN,CONTR,ADDR[DATI]        
    HIGH CPIN:LOW DPIN:HIGH DPIN

    Serout2 PORTB.2, 16572,["DATA IN ",BIN DATI]       
    SEROUT2 PORTB.2, 16572,[$d,$a]

    GOTO START

[mackrackit]

I give up...

[wolwil]

I give up...

Haha! Well at least I learned the problem isn't me

So does anyone out there know the assembly code to make this work???

[mackrackit]

When I get back tonight I am thinking of do some sort of bit banging, maybe that will work.

[Dave]

mackrackit, Why are you using 10 k's for the pullup's? I believe the spec. says 4.7K or lower.. Might be the problem....

Dave Purola,
N8NTA

[mackrackit]

The data sheet for this part call for 10k at 100 kHz and 2k for 400 kHz and 1 MHz.

It did not work at the higher speeds so I was trying it at the slow.

[wolwil]

mackrackit, Why are you using 10 k's for the pullup's? I believe the spec. says 4.7K or lower.. Might be the problem....

Dave Purola,
N8NTA

I am using 4.7K. Sorry I forgot to mention that I was doing that different from the schematic I posted.

Did you get it to work?

[mackrackit]

I have tried several different resistor sizes and still nothing.
I think I am actually communicating with it as it "ACK" backs at me...
Here is my current mess...

'  18F6680  24FC1025
    DEFINE OSC 20
    @ __CONFIG    _CONFIG1H, _OSC_HS_1H
    @ __CONFIG    _CONFIG2H, _WDT_OFF_2H & _WDTPS_128_2H
    @ __CONFIG    _CONFIG4L, _LVP_OFF_4L
    
    TRISF = 0
    PORTF = 0
   
    DPIN    VAR PORTF.6    'I2C DATA PIN
    CPIN    VAR PORTF.7    'I2C CLOCK PIN
    CONTR   CON %10100001  'READ CONTROL
    CONTW   CON %10100000  'WRITE CONTROL
    ADDR_HB    VAR BYTE
    ADDR_LB    VAR BYTE
    DATI    VAR BYTE
    DATO    VAR BYTE
    ACK     VAR BIT
    ADDR_HB = %00000000
    ADDR_LB = %00000000
    DATO = %11100000
    CNT VAR BYTE
    CNT = 0
    
    START:CNT = CNT + 1
    GOSUB WRITE_DATA
    PAUSE 100
    GOSUB READ_DATA
    SEROUT2 PORTB.2, 16572,["TEST ",DEC CNT,$d,$a]
    Serout2 PORTB.2, 16572,["DATA IN ",BIN DATI]      
    SEROUT2 PORTB.2, 16572,[$d,$a]
    PAUSE 500
    GOTO START
    
    WRITE_DATA:  ACK=1   :Serout2 PORTB.2, 16572,["ACK ",BIN ACK,$d,$a] 
    GOSUB START_ROM
    SHIFTOUT DPIN,CPIN,1,[CONTW]
    SHIFTIN DPIN,CPIN,0,[ACK\1]
    Serout2 PORTB.2, 16572,["ACK ",BIN ACK,$d,$a] 
    SHIFTOUT DPIN,CPIN,1,[ADDR_HB]
    SHIFTIN DPIN,CPIN,0,[ACK\1]
    SHIFTOUT DPIN,CPIN,1,[ADDR_LB]
    SHIFTIN DPIN,CPIN,0,[ACK\1]
    SHIFTOUT DPIN,CPIN,1,[DATO]
    SHIFTIN DPIN,CPIN,0,[ACK\1]
    GOSUB STOP_ROM
    PAUSE 10
    RETURN
    
    READ_DATA:
    GOSUB START_ROM
    SHIFTOUT DPIN,CPIN,1,[CONTR]
    SHIFTIN DPIN,CPIN,0,[ACK\1]
    SHIFTOUT DPIN,CPIN,1,[ADDR_HB]
    SHIFTIN DPIN,CPIN,0,[ACK\1]
    SHIFTOUT DPIN,CPIN,1,[ADDR_LB]
    SHIFTIN DPIN,CPIN,0,[ACK\1]
    GOSUB START_ROM
    SHIFTOUT DPIN,CPIN,1,[CONTR]
    SHIFTIN DPIN,CPIN,0,[ACK\1]
    SHIFTIN DPIN,CPIN,0,[DATI\8]
    GOSUB STOP_ROM
    PAUSE 10
    RETURN
    
    START_ROM:
    HIGH CPIN:HIGH DPIN:LOW DPIN:RETURN
    STOP_ROM:
    HIGH CPIN:LOW DPIN:HIGH DPIN:RETURN