SAA7740 View Datasheet(PDF) - Philips Electronics
Part Name
Description
Manufacturer
SAA7740 Datasheet PDF : 28 Pages
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Philips Semiconductors
Digital Audio Processing IC (DAPIC)
Product specification
SAA7740H
Improper acknowledge generated by the DAPIC
If an I2C-bus device, other than DAPIC, is addressed by the master then the DAPIC will generate a short acknowledge
pulse. The DAPIC starts pulling down the SDA line at the trailing edge of the SCL clock pulse. and releases the SDA line
approximately 390 ns after the leading edge of the following SCL LOW-to-HIGH transition (see Fig.8).
This improper acknowledge pulse can cause the I2C-bus master to detect an incorrect acknowledgement, depending on
the capturing moment of the SDA line by the I2C-bus master. Any possible non-acknowledgements of involved I2C-bus
devices, including the SAA7740H, will be masked thus making the system unreliable.
To avoid these problems the I2C-bus master should only capture the SDA line at such a moment that the improper
acknowledge pulse will not be detected.
handbook, full pagewidth
data output
from transmitter
data output
from DAPIC
non-DAPIC device address
improper acknowledge
generated by DAPIC
SCL from
master
1
2
S
START condition
7
8
9
390 ns (typ)
MGK425
Fig.8 Improper acknowledge generated by the DAPIC.
1997 May 30
13
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