TC9446FG Datasheet, PDF (13/41 Pages) Toshiba Semiconductor – Audio Digital Processor for Decode of Dolby Digital (AC-3), MPEG2 Audio

TC9446FG
5) Incorrect operation detection
Incorrect operation detection of the internal program of TC9446FG can be made to perform by
setting the incorrect operation detection start bit in a 24 bit command to “H”. As for this incorrect
operation detection start bit, the reversal output only of the case of MICS terminal = “H” is carried
out from MIACK terminal.
And, since this incorrect operation detection start bit is periodically cleared by “L” when an internal
program is operating normally, MIACK terminal at the time of MICS terminal = “H” is set to “H”
from “L”.
However, since it will stop being cleared if an internal program becomes a incorrect operation state,
as for MIACK terminal at the time of MICS terminal = “H”, the state of “L” will continue.
Thus incorrect operation detection of a program is attained by supervising MIACK terminal at the
time of MICS terminal = “H”. Moreover, although it checks that MIACK terminal is “L” after setting
MICS terminal to “L” in case a MCU starts access to TC9446FG, MCU can judge that an internal
program is a incorrect operation state, when the state of MIACK = “H” continues.
In addition, when a incorrect operation state is detected, it can return from a incorrect operation
state by initializing by transmitting the soft reset command which the reset terminal was set to “L” or
was mentioned above.
The procedure of incorrect operation detection is shown in Figure 6.
MICS = “L”
Checking of MIACK = “L”
(waiting for becoming to MIACK = “L” at the MIACK = “H”)
Transmission of 24 bit command
(starting the incorrect operation detection = 000080h)
When not set to “L” with “H”, it is the state
of incorrect operation.
It starts the incorrect operation detection
by “1”.
MICS = “H”
MIACK = “L”
Program makes to clear the incorrect operation
detection bit
MIACK = “H”
MIACK = “L” is continue at incorrect
operation, as detection bit isn’t cleared.
Figure 6 Procedure of Incorrect Operation Detection
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2005-09-28