isd-t360sb ETC-unknow, isd-t360sb Datasheet - Page 42

• Manufacturer Part Number: isd-t360sb
• Manufacturer: ETC-unknow

ISD-T360SB
MWCLK
MICROWIRE Clock. Serves as the synchronization
clock during communication. One bit of data is
transferred on every clock cycle. The input data is
available on MWDIN and is latched on the clock
rising edge. The transmitted data is output on
MWDOUT on the clock falling edge. The signal
should remain low when switching MWCS.
MWCS
MICROWIRE Chip Select. The MWCS signal is
cleared to 0, to indicate that the VoiceDSP pro-
cessor is being accessed. Setting MWCS to 1
causes the VoiceDSP processor to start driving
MWDOUT with bit 7 of the transmitted value. Set-
ting the MWCS signal resets the transfer-bit counter
of the protocol, so the signal can be used to syn-
chronize between the VoiceDSP processor and
the microcontroller.
To prevent false detection of access to the
VoiceDSP processor due to spikes on the MWCLK
signal, use this chip select signal, and toggle the
MWCLK input signal, only when the VoiceDSP pro-
cessor is accessed.
OUTPUT SIGNALS
MWDOUT
MICROWIRE Data Out. Used for output only, for
transferring data from the VoiceDSP processor to
the microcontroller. When the VoiceDSP processor
receives data it is echoed back to the microcon-
troller on this signal, unless the received data is
0xAA. In this case, the VoiceDSP processor echoes
a command’s return value.
MWRDY
MICROWIRE Ready. When active (0), this signal in-
dicates that the VoiceDSP processor is ready to
transfer (receive or transmit) another byte of data.
This signal is set to 1 by the VoiceDSP processor af-
ter each byte transfer has been completed. It re-
mains 1, while the VoiceDSP processor is busy
2-6
reading the byte, writing the next byte, or execut-
ing the received command (after the last param-
eter has been received). MWRDY is cleared to 0
after reset. For proper operation after a hardware
reset, this signal should be pulled up.
MWRQST
MICROWIRE Request. When active (0), this signal
indicates that new status information is available.
MWRQST is deactivated (set to 1), after the
VoiceDSP processor receives a GSW (Get Status
Word) command from the microcontroller. After
reset, this signal is active (0) to indicate that a reset
occurred. MWRQST, unlike all the signals of the
communication protocol, is an asynchronous line
that is controlled by the VoiceDSP firmware.
SIGNAL USE IN THE INTERFACE PROTOCOL
After reset, both MWRQST and MWRDY are cleared
to 0.
The MWRQST signal is activated to indicate that a
reset occurred. The EV_RESET bit in the status reg-
ister is used to indicate a reset condition.
The GSW command should be issued after reset
to verify that the EV_RESET event occurred, and to
deactivate the MWRQST signal.
While the MWCS signal is active (0), the VoiceDSP
processor reads data from MWDIN on every rising
edge of MWCLK. VoiceDSP processor also writes
every bit back to MWDOUT. This bit is either the
same bit which was read from MWDIN (in this case
it is written back as a synchronization echo after
some propagation delay), or it is a bit of a value
the VoiceDSP processor transmits to the micro-
controller (in this case it is written on every falling
edge of the clock).
When a command has more than one parame-
ter/return-value, the parameters/return-values are
transmitted in the order of appearance. If a pa-
rameter/return-value is more than one byte long,
the bytes are transmitted from the most significant
to the least significant.
Voice Solutions in Silicon
2—SOFTWARE
™