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參數(shù)資料
| 型號(hào)： | T8531 |
| 元件分類： | Codec |
| 英文描述： | T8502 and T8503 Dual PCM Codecs with Filters |
| 中文描述： | T8502和T8503雙的PCM編解碼器與濾波器 |
| 文件頁數(shù)： | 15/48頁 |
| 文件大小： | 999K |
| 代理商： | T8531 |
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Lucent Technologies Inc.
15
Preliminary Data Sheet
November 2000
Codec Chip Set
T8531/T8532 Multichannel Programmable
Chip Set Functional Description
(continued)
T8531 Functional Blocks
(continued)
T8531 System Interface
The system interface is a full-duplex interface used for
the exchange of PCM data with the system. The sys-
tem is the master of this bus. No control information is
transmitted over the system interface; all control
instructions are routed over the microprocessor inter-
face.
The system interface is used for all 16 lines serviced by
the T8531. The PCM data rate is 8 ksamples/s/line,
so the total required channel capacity is 16 x 8 =
128 Kwords/s in each direction. At the 4.096 MHz rate,
each word takes 1.95
μ
s to transmit interleaved with
5.86
μ
s of dead time. The frame sync, SFS, is pre-
sented to the system interface at an 8 kHz rate.
A single bit clock and frame sync are used to control
both the transmit and receive directions. The beginning
of the first time slot in a frame is identified from the SFS
input (see Figure 9). In nondelayed mode, SFS is
active coincident with bit 0 of time slot 0 of the RX
frame (and the TX frame if the programmed offset
between TX and RX is 0). In delayed mode, SFS is
active one cycle earlier.
The amount of skew or offset between the transmit and
receive frames and time slots is programmable via
board control word 2, 0x1FFC. The bit offset is up to a
frame, i.e., up to 511 bits in 4 MHz mode. The bit offset
skew takes place in the system PCM interface block.
The active transmit and receive time slots are deter-
mined by the card address. The number of time slots
within a frame varies according to the rate of SCK. Only
16 time slots are ever active in a frame, as shown in
Table 3.
The T8531 obtains its card address in board control
word 1, 0x1FFE.
In
μ
-law or A-law mode, each PCM word is only 8 bits
long and occupies one time slot. In linear mode, the
PCM word is 16 bits long and occupies two adjacent
time slots. The MSB is the first bit clocked out in the
valid time slot, and the LSB is the last bit of the follow-
ing (invalid) time slot.
T8531 Microprocessor Interface
This interface between the microprocessor (or other
external controller) and the T8531 device carries user-
supplied program variables and control and test
instructions to both the T8531 and the T8532 octal
converters. The external device is the master of the
microprocessor interface. The interface is serial and
asynchronous, and consists of four pins (UPCK,
UPCS, UPDI, UPDO). The data rate is determined by
the customer’s choice of external device, but may not
exceed 4.096 MHz. Microprocessor interface com-
mands consist of two words, address and data.
Address and data are 16 bits wide. The T8531 expects
an address first. The first bit of the address word is the
R/W flag, which tells the T8531 whether it must receive
or send data (receive, R/W = 0; send, R/W = 1).
Addresses less than 0x1400 refer to the DSP engine
RAM space. If a read from the DSP engine is required,
the microprocessor interface issues a read interrupt to
the DSP engine. If it's a write to the DSP engine, the
microprocessor interface shifts in the data word and
saves it into the data register before sending a write
interrupt to the DSP engine. Once in every 7.8
μ
s time
segment, the DSP engine checks whether an interrupt
is outstanding from the microprocessor interface block.
If so, the DSP engine reads the address register. If it's
a read, the DSP engine fetches the word from RAM,
places it in the data register, and shifts it out to the
microprocessor. If it's a write, it puts the contents of the
data register into RAM.
Table 3. Active Time-Slot Spacing in a PCM Bus Frame
SCK Rate (MHz)
2.048
Total # of Time Slots
32
Card Address
0
1
0
1
2
3
Valid Time Slots
0, 2, 4, . . . 30
1, 3, 5, . . . 31
0, 4, 8, . . . 60
1, 5, 9, . . . 61
2, 6, 10, . . . 62
3, 7, 11, . . . 63
Invalid Time Slots
1, 3, 5, . . . 31
0, 2, 4, . . . 30
1—3, 5—7, . . . 61—63
0, 2—4, 6—8, . . . 62—63
0—1, 3—5, 7—9, . . . 63
0—2, 4—6, 8—10, . . . 60—62
4.096
64
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| T8532 | T8502 and T8503 Dual PCM Codecs with Filters |
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| T8535B | T8535B/T8536B Quad Programmable Codec |
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| T8531A | 制造商:AGERE 制造商全稱:AGERE 功能描述:T8531A/8532 Multichannel Programmable Codec Chip Set |
| T8532 | 制造商:AGERE 制造商全稱:AGERE 功能描述:T8531A/8532 Multichannel Programmable Codec Chip Set |
| T8533 | 制造商:AGERE 制造商全稱:AGERE 功能描述:T8533/34 Quad Programmable Line Card Signal Processor |
| T85331G | 制造商:BITECH 制造商全稱:Bi technologies 功能描述:Thick Film Super Low Profile SIP Resistor Networks |
| T85331J | 制造商:BITECH 制造商全稱:Bi technologies 功能描述:Thick Film Super Low Profile SIP Resistor Networks |
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