SPo3 and I2C

Hi all.

I need what might be some basic help with some I2C code.

I have a SP03 module and the I2C specs for that are on http://www.robot-electronics.co.uk/htm/Sp03doc.shtml
I am using a 16f877 with 20 mhz crystal. Basically for now I need to read the command status? Can anyone offer a suggestion? Also are the pins I have selected to use for Data and Clock ok on the 877 or should I be using specific pins? Do they need pull up resistors? I have tried different varioations of code and can't get a response....


My code

DEFINE OSC 20
define i2c_slow 1' Tried this as a test


Wdog Var Portb.7
DPIN var PORTB.6 ' I2C data pin
CPIN var PORTB.5 ' I2C clock pin
talk var portd.2 ' Indicate still busy
NOP CON 0
B1 var byte


High talk 'Unit talks on power up. So indicate
loop:
Toggle wdog
pause 200
I2CREAD DPIN,CPIN,$C4,[B1] 'Read if still talking

if b1 > 0 then goto loop
low talk
goto loop

Quote:

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Also are the pins I have selected to use for Data and Clock ok on the 877 or should I be using specific pins? Do they need pull up resistors?

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Your selected pins are O.K. Yes you need external Pull-ups ... 4.7K is a common used value.

Thanks for the help so far. I will give it a go.

Do I also need the define i2c_slow 1? I read the manual as it is needed if speed is over 4 megs so I take it as yes?

Hi fatboylives, They say they test it over 1MHZ I2C clock so you don't need the define. In PBP I2c SLOW is 100KHZ when not 400KHZ

What happened to your previous post. When I logged in to read your reply re the Define part, I went back to read your earlier post and grab the code and there is none there? I can only see the


quote:
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Also are the pins I have selected to use for Data and Clock ok on the 877 or should I be using specific pins? Do they need pull up resistors?
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Your selected pins are O.K. Yes you need external Pull-ups ... 4.7K is a common used value.




part. The code you provided has vanished....

Does this happen or am I just over tired?

Nop, i remove the code myself. I was really not sure of the way we have to talk to this module. Info are not so clear... maybe i'm a pure idiot and over-tired myself too.

I see different way to access. So i bet we can read from control register like

ModuleAddress = $C5
CommandRegister = 0
I2CREAD DPIN,CPIN,ModuleAddress,CommandRegister,[B1]

or

ModuleAddress = $C4
CommandRegister = 0
I2CWRITE DPIN,CPIN,ModuleAddress,[CommandRegister]

ModuleAddress = $C5
I2CREAD DPIN,CPIN,ModuleAddress,[b1]

i don't know :-(

Is there any reason your example shows moduleaddress as $C4 on the write and $C5 on the read? Shouldn't they be the same.

I might have to use serial instead of I2C if I cannot get it to work...

Currently I get various values returned and nothi9ng makes sense....... Not unusual for me :-)