AMBE2000 ETC, AMBE2000 Datasheet - Page 21

• Manufacturer Part Number: AMBE2000
• Description: VOCODER CHIP
• Manufacturer: ETC

4.3
The signals in Table 4-C make up the serial channel interface. The serial channel mode transfers data in and out of the AMBE-
2000™ using 16 bit words on the two data lines CHAN_RX_DATA and CHAN_TX_DATA. The selection of the
formatted or unformatted format of this data is made using information in Table 4-A.
Note 1:The AMBE-2000 expects an encoder packet to be read approximately every 20 msec. Following the initial
reset, wait for EPR to go low and read the initial packet (t0). 20 msec later, the next packet (t1) should be ready.
For packet t1 and all following packets use the procedure below:
1) Wait for slightly less than 20 msec.
2) Assert CHAN_TX_STB and read word on CHAN_TX_DATA.
3) If transmitted word not 0x13EC, discard it and repeat step 2.
4) If transmitted word 0x13EC, read 23 more words (rest of packet).
A new packet should be ready every 20 msec after the initial EPR high to low transition. A packet read should take place
every 20 msec. If there is a delay in the read (i.e. a packet is missed), it is recommended that the device be reset.
CHAN_RX_DATA
CHAN_RX_STRB
CHAN_TX_DATA
CHAN_TX_STRB
CHAN_RX_CLK
CHAN_TX_CLK
Symbol
EPR
Pin
Channel Serial Mode
Table 4-C Channel Serial Interface Pin Descriptions
Direction
Output/
Passive
Active
Input
Out
Out
Pin
In
In
In
In
Number
Confidential Proprietary, Subject to Change
Pin
20
32
28
30
42
34
38
Description
Encoder Packet Ready: Following a reset, this output signal will have a
high to low transition to indicate that the encoder has a frame of data to
output. The next packet will be ready approximately 20 msec later. See
Note 1.
Serial Data Input: 16 bits of channel data are input on CHAN_RX_DATA,
synchronous to CHAN_RX_CLK, with each CHAN_RX_STRB pulse.
Serial
CHAN_RX_DATA is latched by the AMBE-2000™ on the falling edges of
CHAN_RX_CLK.
Input (Write) Data Strobe: This signal indicates to the AMBE-2000™
when the data on CHAN_RX_DATA will be latched by CHAN_RX_CLK.
See Figure 4-B.
Serial
CHAN_TX_DATA,
CHAN_TX_STRB pulse.
Serial Output Clock: In coordination with CHAN_TX_STRB, the data on
CHAN_TX_DATA is output by the AMBE-2000™ on the falling edges of
CHAN_TX_CLK.
Output (Read) Data Strobe: This signal indicates to the AMBE-2000™
when to bring the data to the CHAN_TX_DATA pin. See Figure 4-B.
User’s Manual Version 3.0
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Output:
Clock:
synchronous
16
In
bits
coordination
of
to
channel
CHAN_TX_CLK,
with
data
CHAN_RX_STRB,
are
with
output
each
on