4 Sep
2009
4 Sep
'09
5:28 p.m.
On Fri, 2009-09-04 at 10:12 -0500, Timur Tabi wrote:
Wolfgang Denk wrote:
Wrong Question. I don't know enough about the I2C protocol. Why is i2c_wait4bus necessary?
Ok, why is it necessary?
Freescale's I2C core supports multiple masters. I'd guess that i2c_wait4bus() is used to ensure the bus is not in use by a different master before initiating a read or write. Its polling the MBB status bit, which is automatically set/cleared when the controller sees a START/STOP which supports this.
If this is the case, the timeout should be the maximum (or reasonable maximum) time an I2C transaction could take.
Best, Peter