IDT821064 Ver la hoja de datos (PDF) - Integrated Device Technology
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IDT821064 Datasheet PDF : 33 Pages
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IDT821064 QUAD PROGRAMMABLE PCM CODEC WITH GCI INTERFACE
Table 1 - Time Slot Selection for Compressed GCI
INDUSTRIAL TEMPERATURE RANGE
IDT821064
Channels
1
2
3
4
S1=0,S0=0
Time Slot
Voice
Channel
Time slot 0
A
Time slot 0
B
Time slot 1
A
Time slot 1
B
S1=0,S0=1
Time Slot
Voice
Channel
Time slot 2
A
Time slot 2
B
Time slot 3
A
Time slot 3
B
S1=1,S0=0
Time Slot
Voice
Channel
Time slot 4
A
Time slot 4
B
Time slot 5
A
Time slot 5
B
S1=1,S0=1
Time Slot
Voice
Channel
Time slot 6
A
Time slot 6
B
Time slot 7
A
Time slot 7
B
In compressed operation, two GCI time slots are required to access
the four channels of IDT821064. The GCI time slot assignment is
determined by S1 and S0 as shown in Table 1.
LINEAR GCI MODE
In GCI linear mode, one GCI frame consists of 8 GCI time slots, each
GCI time slot consists of four 8-bits bytes. Four of the 8 GCI time slots
are used as Monitor Channel and C/I octet, they have a common data
structure:
- Two don’t_care bytes.
- One Monitor Channel byte, which is used for reading/writing control
data/coefficients from/to the device for Channel A and B.
- One C/I byte, which contains a 6 bit width C/I channel sub-byte together
with an MX bit and an MR bit. All real time signaling information is carried
on the C/I channel sub-byte. The MX (Monitor Transmit) bit and MR
(Monitor Receive) bit are used for handshaking functions for Channel A
and B. Both MX and MR bits are active low .
Other four GCI time slots are used for linear voice data (a 16-bit 2’s
complement number, b15 and b14 are the same as b13, which is the
sign bit, b13 to b0 are effective bits). Each GCI time slot consists of two
16-bit linear voice data bytes: one byte contains the linear voice data for
Channel A, the other byte contains the linear voice data for Channel B.
The GCI time slot assignment is determined by S1 and S0 pin. When
S0 and S1 are both low, the linear GCI Frame Structure is shown in
Figure 2.
In linear operation, because one chip of the four-channel IDT821064
occupies four GCI time slots ( two for voice data and two for C/I and
monitor), the rest four GCI time slots can be used by other device. There
are four locations in the 8-time-slots GCI bus for one IDT821064 to select,
see Table 2.
125 µs
FSC
DCL
DD
DU
Detail A
DD
TS0 TS1 TS2 TS3 TS4 TS5 TS6 TS7
Detail A
Detail B
TS0 TS1 TS2 TS3 TS4 TS5 TS6 TS7
TS0-1 for Monitor and C/I
TS2-3 for Linear Voice
Data
Unused
Unused
Monitor Channel C/I Channel
MM
RX
DU
Unused
Unused
Monitor Channel C/I Channel
MM
RX
Detail B
DD
DU
16-bit Linear Voice Data for Channel A
16-bit Linear Voice Data for Channel B
16-bit Linear Voice Data for Channel A
16-bit Linear Voice Data for Channel B
Figure 2. Linear GCI Frame Structure
5
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