On Sun, 13 Jul 2008 02:12:36 -0700, David Brownell wrote: > > 3. for chips like max732x, actually, the range of 0x50 - 0x5F will be > > monitored by the I2C chips at startup to decide the connections of > > AD2/AD0 pins to GND/VCC/SCL/SDA, > > There's no need to monitor addresses ... before the first data bit > is sent -- whatever value! -- it's known how those pins are wired: > > - START bit ... SCL is high, SDA falls. Any pin that stayed > low is wired to ground. Any pin that changed high-to-low is > thus connected to SDA. > > - Prepare to send first bit ... SDA still low, SCL falls. Any > pin that stayed high is wired to Vcc. Any pin that changed > high-to-low is connected to SCL. > > And then the master updates SDA to match the first (address) bit, > and lets SCL be pulled high ... the i2c slave has all the data it > needs to be able to determine its address.
Totally true. Add to this that the first 3 address bits can't change, this gives the chip some more time to setup its internal logic to match the 4 LSBs by the time they come. -- Jean Delvare _______________________________________________ i2c mailing list [email protected] http://lists.lm-sensors.org/mailman/listinfo/i2c
