Princeton Technology Corp.
6-Channel Electronic Volume Controller IC
Byte Format
Tel : 886-2-29162151
Fax: 886-2-29174598
URL:
http://www.princeton.com.tw
Preliminary
PT2258
Every byte transmitted to the SDA Line consists of 8 bits. Each byte must be followed by an Acknowl-
edge Bit. The MSB is transmitted first.
Acknowledge
During the Acknowledge Clock Pulse, the master (µP) puts a resistive HIGH level on the SDA Line.
The peripheral (audio processor) that acknowledges has to pull-down (LOW) the SDA line during the
Acknowledge Clock Pulse so that the SDA Line is in a Stable Low State during this Clock Pulse. Please
refer to the diagram below.
The audio processor that has been addressed has to generate an Acknowledge after receiving each byte,
otherwise, the SDA Line will remain at the High Level during the ninth (9th) Clock Pulse. In this case,
the master transmitter can generate the STOP Information in order to abort the transfer.
Transmission without Acknowledge
If you want to avoid the acknowledge detection of the audio processor, a simpler µP transmission may
be used. Wait one clock and do not check the slave acknowledge of this same clock then send the new
data. If you use this approach, there are greater chances of faulty operation as well as decrease in noise
immunity.
PT2258 pre1.0
6
Updated July 2000
PTC [ PRINCETON TECHNOLOGY CORP ]
