ISO-CMOS
Write Connect Memory - Set Connection Mode
(Cmd0-1: 0,1)
The corresponding output channel to the
addressed Connect Memory location is
configured in connection mode. The Connection
Mode Data Byte (Table 2) will be received by the
MT8982 in the following data byte. Bits 0 to 4
(SC0-SC4) select the source input channel for
switching to this output channel. Bit 5 (STi)
selects the input stream. Bit 6 (ODE) enables/
disables tristate for this channel. Bit 7 is unused
in connection mode.
Read Data Memory (Cmd0-1: 1,0)
The contents of the addressed Data Memory
location are transmitted to the microcontroller in
the following data byte.
Write Connect Memory - Set Message Mode
(Cmd0-1: 1,1)
The corresponding output channel to the
addressed Connect Memory location is
configured in message mode. The following data
byte will be received by the MT8982 and written
to the address Connect Memory location. The
data byte will be output directly to the
corresponding output channel.
The following example shows a typical programming
sequence for the MT8982. A connection is to be
made from stream 1 channel 6 to stream 0 channel
15:
•
•
The microcontroller pulls CS low.
The microcontroller transmits eight clock pulses
to SCLK and a Command/Address byte, HEX
3E, to RxD.
The Command/Address byte
addresses output channel 15, stream 0,
configures that channel as connection mode
and identifies the microcycle as a write to the
Connect Memory.
The microcontroller transmits another eight
clock pulses to SCLK and sends the
Connection Mode Data Byte, HEX 26, to RxD.
The Connection Mode Data Byte addresses
input channel 6, stream 1 in the Data Memory.
Note that at least two microseconds must occur
between the two accesses.
•
MT8982
The connection is now complete.
The
microcontroller may now check that the connection is
correct:
•
The microcontroller transmits eight clock pulses
to SCLK and a Command/Address byte, HEX
3C, to RxD.
The Command/Address byte
addresses output channel 15, stream 0 and
identifies the microcycle as a read from the
Connect Memory.
The microcontroller transmits another eight
clock pulses to SCLK. The MT8982 outputs the
Connect Memory data, HEX 26, on TxD. At
least two microseconds must occur between
the two accesses to ensure that the MiniDX can
clock out the data.
CS goes high to terminate the session.
•
This connection is only in one direction. To make a
bidirectional connection the MT8982 must also be
programmed to connect stream 0 channel 15 to
stream 1 channel 6.
Serial Bus Mode
When the microport is in serial bus mode the
MT8982 is programmed via the two ST-BUS serial
streams CSTi0 and CSTi1. Each channel in these
two streams is written directly into the corresponding
address in the Connect Memory. The data written to
the Connect Memory is always the Connection Mode
Data Byte as described in Table 2. To set up a
connection, the Connection Mode Data Byte is
transmitted to the MT8982 on the CSTi stream and
channel number which is the same as the desired
STo stream and channel number. As long as the
device remains in serial bus mode, the Connection
Mode Data byte must be transmitted continuously,
every frame, to maintain the connection.
Message mode is not available when the device is in
serial bus mode. Also, neither the Connect Memory
nor the Data Memory can be read while the device is
in serial bus mode. MITEL’s MT8980, MT9080 and
MT8920 devices can all be used as programmable
parallel-to-ST-BUS serial interfaces for CSTi0 and
CSTi1.
Initialization
On power up the contents of the Connect Memory
can be in any state. In order to prevent false
programming of peripheral ST-BUS devices or false
data transmission, ODE should be kept low during
power up. This will keep the two TDM outputs in high
impedance until the MT8982 Connect Memory is
programmed.
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MITEL [ MITEL NETWORKS CORPORATION ]
