TC9446FG Datasheet, PDF (20/41 Pages) Toshiba Semiconductor – Audio Digital Processor for Decode of Dolby Digital (AC-3), MPEG2 Audio

TC9446FG
4) ON/OFF of soft reset
The case where a program is started after program boot, and in restarting a program, it performs
ON/OFF of soft reset. ON/OFF of soft reset are performed by carrying out and transmitting the bit of
the soft reset in a 24 bit command to “H” (ON) and “L” (OFF).
Since data with which ON/OFF of soft reset follows a command is not required, STOP Condition is
transmitted after 24 bit command transmission.
In addition, in order to return from a incorrect operation state, when turning ON soft reset, it is
also possible to transmit a 24 bit command irrespective of the state of ACK bit.
The procedure of ON/OFF of soft reset is shown in Figure 14.
START Condition
Transmission of I²C Address (3Ah)
At the time of ACK = “H”, it resumes from
START Condition. However, it is possible
to disregard and carry out command
transmission of the ACK bit at the time of
a reckless run.
Checking of ACK bit = “L”
Transmission of 24 bit command
(soft reset ON/OFF = 0000x0h)
Soft reset ON: Bit = “1”.
Soft reset OFF: Bit = “0”.
STOP Condition
Soft reset ON/OFF
Figure 14 Procedure of ON/OFF of Soft Reset
5) Incorrect operation detection
Incorrect operation detection of the internal program of TC9446FG is judged by the existence of the
reaction to the access demand from a MCU. Therefore, R/W of data need to be performed from a MCU
to TC9446FG at the interval of about 6 ms or more.
ACK bit is set to “L”, when the following access demand opens the interval of about 6 ms or more
and is performed, since R/W of data were performed between about 6 ms back to the access demand
from a MCU when TC9446FG were operating normally.
However, if TC9446FG become a incorrect operation state, even if it is going to stop receiving the
access demand from a MCU, it is going to open the interval of about 6 ms or more and MCU is going
to make it access again, it will become a state ACK bit is “H” continued.
A MCU can perform incorrect operation detection by seeing this ACK bit.
That is, since TC9446FG are in a incorrect operation state when it is “H” fixation, even if ACK bit
passes about 6 ms or more, ACK bit is disregarded, soft reset is turned ON, and each setup of
TC9446FG is performed again.
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2005-09-28