Pin A2 needed to be tied to VCC not VSS in order for the chip to be enabled. This however has not fixed my problem I am still getting nothing written to it.
I found 1 problem with my circuit.
Pin A2 needed to be tied to VCC not VSS in order for the chip to be enabled. This however has not fixed my problem I am still getting nothing written to it.
I think I found another issue with the circuit.
I believe I have the SDA and SCL pins going to the wrong pins on the 16F88. I have them right now going to PORTA.0 for SDA and PORTA.1 for SCL. I believe they need to be set as PORTB.1 for SDA and PORTB.4 for SCL with the 16F88. I will try this tonight and post my findings.
Getting "255" from the read and not "0"
Well I have new results but still not looking like I am writing to the chip. Now when I read I get 255 for an output and not 0. I don't know if the 24FC1025 is default all 1's or 0's. Here is the new Code:
Hyperterm is giving me this:Code:SO con 0 ' Define serial output pin T2400 con 0 ' Define serial mode cont CON %10100000 ' Define Control byte addr CON %0000000000000111 ' 2 Byte Address of 7 B1 VAR BYTE ' Var for data being read B1 = 0 ' Set B1 to 0 to rule out 255 coming from that I2CWRITE PORTB.1,PORTB.4,cont,addr,[20] ' Send the byte 1 to address 7 PAUSE 10 ' Wait 10ms for write to complete I2CREAD PORTB.1,PORTB.4,cont,addr,[B1] ' Read address 7 into B1 Serout SO,T2400,["Addr",#addr,":",#B1,13,10] ' Print B1's Value in DEC
Any help would be appreciatedCode:Addr7:255 Addr7:255 Addr7:255 Addr7:255
Table 2-1 of the data sheet Says this about pin A2
If you are still using the schematic from MeLabs then...Non-Configurable Chip Select.
This pin must be hard wired to
logical 1 state (VCC). Device
will not operate with this pin
left floating or held to logical 0
(VSS)
The other thing I see in the data sheet is the last bit of the control byte sets Read or Write.
0 = READ
1 = WRITE
And you may have to add this but try the above stuff firstCode:contR CON %10100000 contW CON %10100001 I2CWRITE PORTB.1,PORTB.4,contW,addr,[20] PAUSE 10 'Is that long enough? I2CREAD PORTB.1,PORTB.4,contR,addr,[B1]
DEFINE I2C_SLOW 1
But all the above might be a bunch of hooey. I have not used this chip...
Dave
Always wear safety glasses while programming.
Still doesn't work
Nope I found that mistake of mine earlier and fixed itIf you are still using the schematic from MeLabs then...
Yeah this one amazes me with PBP having an I2CREAD and a I2CWRITE command but yet you still have to tell it to READ or WRITE?!?!?!The other thing I see in the data sheet is the last bit of the control byte sets Read or Write.
0 = READ
1 = WRITE
Just to clarify I found this under section 5.0 saying that a READ operation should be a 1 and WRITE should be a 0
The last bit of the control byte defines the operation to
be performed. When set to a one, a read operation is
selected, and when set to a zero, a write operation is
selected.Yes I believe so because the 24FC1025 only has a 5ms delay neededPAUSE 10 'Is that long enough?
I tried it and got the same results, nothing but 255's.And you may have to add this but try the above stuff first
DEFINE I2C_SLOW 1
Do you know if the 24FC1025 is flashed with all 0's or all 1's from the factory? Before I was getting %00000000 from var B1 and now I am getting %11111111 but I want to know if its actually reading that or if its a blip in the coding.
Here is the updated code:
I added a 2nd byte to check an address I have not written to and also get a 255 from that but early on in the code I set B1 and B0 to 0 and its getting changed somehow. So either I am reading all 1's from the addresses or the code is screwy.Code:DEFINE I2C_SLOW 1 SO con 0 ' Define serial output pin T2400 con 0 ' Define serial mode contR CON %10100001 ' Define Control byte contW CON %10100000 ' Define Control byte addr CON %0000000000000111 ' 2 Byte Address of 7 D1 CON %00000111 B0 VAR BYTE ' Var for data being read B1 VAR BYTE ' Var for 2nd byte being read b0 = 0 b1 = 0 I2CWRITE PORTB.1,PORTB.4,contW,addr,[D1] ' Send the byte 1 to address 7 PAUSE 10 ' Wait 10ms for write to complete I2CREAD PORTB.1,PORTB.4,contR,addr,[B1,B0] ' Read address 7 into B1 ' and address 8 into B0 Serout SO,T2400,["Addr",#addr,":",#B1," and then ",#B0,13,10] ' Print
PS sorry about the novel here, but its late and I tend to ramble when I'm tired.
Other notes:
I am using a 4MHz external clock to run the show if that matters. I will be switching to a 20MHz once I have everything working.
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.
Code:' 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
Dave
Always wear safety glasses while programming.
I give up...
Dave
Always wear safety glasses while programming.
Members who have read this thread : 0You do not have permission to view the list of names.
Posting Permissions
Bookmarks