ACE9050 datasheet(36/52 Pages) MITEL

36 / 52 page

ACE9050

SQLEV

[3:0]

Samples

AMPS %

(50 samples)

TACS %

(63 samples)

0000

0001

0010

0011

0100

0101

0110

0111

1000

1001

1010

1011

1100

1101

1110

1111

100

Table 72 Squelch level settings

Word Sync Detector

The Word Sync Detector contains the hardware to detect the

Barker code, synchronise the received bytes to the incoming

data frame, extract Busy/Idle bits and update the RXD and

SQRX registers. It also generates the IRQ-WS, IRQ-RX and

IRQ-BI-SAT interrupts. The hardware has four modes of operation

which can be selected by software.

The Barker code sequence is used for achieving frame

synchronisation to the incoming data word boundaries. It occurs

in a message after the dotting sequence and before the first data

word. The hardware detection circuit is an 11-bit serial shift

the Barker code (11100010010). The action upon detecting

word sync depends on the mode of the hardware.

The Word Sync Detector contains a parallel register, into

which the incoming data, RXD, is clocked. When the hardware

is in the appropriate mode the Busy/Idle bits are removed from

the data sequence before being fed to the Data Receive (RXD)

the Squelch level flag is set for an eight-bit byte and stores this

in the SQRX register. The Word Sync Detector contains byte and

frame counters which generate the IRQ-RX interrupt when the

data and squelch registers are updated. The software must

ensure these registers are read within the suitable time frame

after IRQ-WS to avoid losing data.

Associated Registers

VC_CCN Voice/Control Channel MODPRT0 bit0 (Table 73)

This bit allows the software to control the mode of the Word

Sync Detector between Control channel and Voice channel. It

also operates in conjunction with the ENWS bit; VC_CCN must

be set to reflect the category of the current channel.

ENWS Enable Word Sync MODPRT 0 [1] (Table 74)

This bit allows the software to control the mode of the Word

Sync Detector between ‘Sync on Barker’ and ‘ Not Sync on

Barker’. It also operates in conjunction with the VC_CCN bit.

VC_CCN

Control channel

Voice channel

Mode

Table 73

ENWS

Description

Data will not reframe if a Barker code is detected

Data will reframe if a Barker code is detected

NOTE: Regardless of the setting of ENWS the IRQ-WS will be

generated on detection of a Barker code.

Table 74

RXD[7:0] MODPRT2 Read (Table 75)

This register contains the data from a forward channel (FVC

or FOCC) segmented into 8-bit chunks.

Bit

7: 0 RXD[7:0] Data byte received

Name

Function

Table 75

The first bit received goes to the most significant bit of the

All other data on the Control channel and all data on the voice

channel will be present in the registers. This includes the dotting

and Barker sequences. The IRQ-RX interrupt occurs when the

registers have been updated.

SQRX[3:0] MODPRT1[3:0] Read (Table 76)

These four bits contain the number of bits in the present

received byte that have surpassed the Squelch threshold set. It

will thus contain a number between 0 and 8. This register is

updated at the same time as the RXD register.

SQRX [3:0]

Number of bits surpassing Squelch level

0000

0001

0010

0011

0100

0101

0110

0111

1000

1001 to 1111

Not valid

Table 76 Possible Squelch readings

B_I MODPRT1[6] Read (Table 77)

This bit is the extracted Busy/Idle bit from a Control channel

data stream. Note that an IRQ-BI-SAT interrupt occurs when this

bit is updated.

B_I

Busy/Idle bit

Table 77

Modes of Operation

The Word Sync Detector has four modes of operation. The

modes affect how Busy/Idle bits a handled, the function of the

IRQ-BI-SAT interrupt and the action of the Word Sync Detector

upon finding a Barker code in the incoming data stream. The

modes are selected via the VC_CCN and ENWS bits, as shown

in Table 78.

ACE9050 датащи(PDF) 36 Page - Mitel Networks Corporation

ACE9050 датащи(HTML) 36 Page - Mitel Networks Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52

датащи скачать

ссылки URL