LPCXpresso IDEのトピックRe: i2c not working

i2c not working

lpcware — Wed, 15 Jun 2016 23:45:06 GMT

Content originally posted in LPCWare by kevin on Fri Feb 15 06:04:52 MST 2013
The problem is that, having sent the seven address bits plus the W bit the ninth bit is logic high and then returns me an error.
Does anyone know what might be the problem.

Re: i2c not working

lpcware — Wed, 15 Jun 2016 23:45:07 GMT

Content originally posted in LPCWare by serge on Fri Feb 15 06:54:35 MST 2013
Where does the ninth bit come from?

Re: i2c not working

lpcware — Wed, 15 Jun 2016 23:45:08 GMT

Content originally posted in LPCWare by frame on Fri Feb 15 08:21:07 MST 2013

Quote: kevin
The problem is that, having sent the seven address bits plus the W bit the ninth bit is logic high and then returns me an error.
Does anyone know what might be the problem.

The slave is assumed to pull SDA low during the 9.th bit, commonly referred to as "Acknowledge".
If he does not, he might not feel addressed. Either the address you send
is really incorrect (i.e. not the address of the slave), or he is in some unknown state,
because he catched some noise on the bus during startup.

I hope your bus pull-up is properly dimensioned.