isd-t360sb ETC-unknow, isd-t360sb Datasheet - Page 43

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

2—SOFTWARE
The MWRDY signal is used as follows:
The MWRQST signal is used as follows:
Figure 1-27 and Figure 1-28 illustrate the se-
quence of activities during a MICROWIRE data
transfer between VoiceDSP and the microcon-
troller.
ISD
1. Active (0) MWRDY signals the microcontrol-
2. The MWRDY signal is deactivated (set to 1
3. The MWRDY signal is activated (cleared to
4. When a return value is transmitted, the
5. The MWRDY signal is activated (cleared to
1. The MWRQST signal is activated (cleared to
2. The MWRQST signal remains active (0), until
ler that the last eight bits of data transferred
to/from the voice module were accepted
and processed (see below).
by the VoiceDSP processor) after 8-bits of
data were transferred to/from the VoiceDSP
processor. The bit is set following the falling
edge of the eighth MWCLK clock-cycle.
0) by the VoiceDSP processor when it is
ready to receive the first parameter byte (if
there are any parameters) and so on till the
last byte of parameters is transferred. An
active MWRDY signal after the last byte of
parameters indicates that the command
was parsed and (if possible) executed. If
that command has a return value, the mi-
crocontroller must read the value before is-
suing a new command.
MWRDY signal is deactivated after every
byte, and activated again when the
VoiceDSP processor is ready to send anoth-
er byte, or to receive a new command.
0) after reset, and after a protocol time-out.
(See “INTERFACE PROTOCOL TIME-OUTS”)
0), when the status word is changed.
the VoiceDSP processor receives a GSW
command.
INTERFACE PROTOCOL TIME-OUTS
Depending on the VoiceDSP processor’s state, if
more than 100 milliseconds elapse between the
assertion of the MWRDY signal and the transmis-
sion 8th bit of the next byte pertaining to the same
command transaction, a time-out event occurs,
and the VoiceDSP processor responds as follows:
ECHO MECHANISM
The VoiceDSP processor echoes back to the mi-
crocontroller all the bits received by the VoiceDSP
processor. Upon detection of an error in the echo,
the microcontroller should stop the protocol
clock, which eventually causes a time-out error
(i.e., ERR_TIMEOUT bit is set in the error word).
For commands that have a return value, the mi-
crocontroller must transmit a byte value of 0xAA
for each byte returned. In response, the VoiceDSP
processor transmits the return values instead of
echoing the 0xAA byte.
Upon detection of an error the VoiceDSP proces-
sor activates the MWRQST signal, and sets the
ERR_COMM bit in the error word.
1. Sets the error bit in the status word to 1.
2. Sets the EV_TIMEOUT bit in the error word to
3. Activates the MWRQST signal (clears it to 0).
4. Activates the MWRDY signal (clears it to 0).
5. Waits for a new command. (After a time-
1.
out occurs, i.e., the microcontroller re-
ceived MWRQST during the command
transfer, or result reception, the microcon-
troller must wait at least four milliseconds
before issuing the next command.)
ISD-T360SB
2-7