MT9075A Mitel Networks Corporation, MT9075A Datasheet - Page 15

• Manufacturer Part Number: MT9075A
• Description: E1 Single Chip Transceiver
• Manufacturer: Mitel Networks Corporation

Preliminary Information
Transmit AIS Operation
The pin TAIS (Transmit AIS, pin 60 in PLCC, pin 48 in
MQFP) allows an all ones signal to be transmitted
from the point of power-up without the need to write
any control registers. During this time the IRQ pin is
tristated. After the interface has been initialized
normal operation can take place by making TAIS
high.
National Bit Buffers
Table 7 shows the contents of the transmit and
receive Frame Alignment Signals (FAS) and Non-
frame Alignment Signals (NFAS) of time slot zero of
a PCM 30 signal. Even numbered frames (CRC
Frame # 0, 2, 4,...) are FASs and odd numbered
frames (CRC Frame # 1, 3, 5,...) are NFASs. The bits
of each channel are numbered 1 to 8, with bit 1 being
the most significant and bit 8 the least significant.
Transmit MFAS (CAS)
Per Time Slot Control
ABCD Bit Debounce
Tx Message Buffer
Transmit non-FAS
CRC Interworking
Error Insertion
RxMF Output
Transmit FAS
Loopbacks
Signalling
Function
Data Link
Interrupts
Counters
HDLCs
Buffer
Mode
Table 6 - Reset Status
interrupts not suspended
All locations set to 54H
Signalling Multiframe
Interrupt Mask Word
All locations cleared
Zero unmasked, all
others masked;
CAS Registers
1/S
Deactivated
Deactivated
Deactivated
Deactivated
Deactivated
Termination
C
00001111
Activated
n
Cleared
Status
n
0011011
1111111
Table 8 illustrates the organization of the MT9075A
transmit and receive national bit buffers. Each row is
an addressable byte of the MT9075A national bit
buffer, and each column contains the national bits of
an odd numbered frame of each CRC-4 Multiframe.
The transmit and receive national bit buffers are
located at page 0DH and 0EH respectively.
Note that the Data Link (DL) pin functions, if
selected, override the transmit national bit buffer
function.
ssable
NBB0 S
NBB1 S
NBB2 S
NBB3 S
NBB4 S
CRC
Addre
Bytes
0/FAS
1/NFAS
2/FAS
3/NFAS
4/FAS
5/NFAS
6/FAS
7/NFAS
8/FAS
9/NFAS
10/FAS
11/NFAS
12/FAS
13/NFAS
14/FAS
15/NFAS
Table 8 - MT9075A National Bit Buffers
Table 7 - FAS and NFAS Structure
Frame/
Frames 1, 3, 5, 7, 9, 11, 13 & 15 of a CRC-4
Type
F1
CRC
a4
a5
a6
a7
a8
indicates position of CRC-4 multiframe alignment signa
S
S
S
S
S
F3
a4
a5
a6
a7
a8
C
C
C
C
C
C
C
E
C
E
1
0
0
1
0
1
1
1
2
1
2
3
4
1
2
3
4
S
S
S
S
S
F5
a4
a5
a6
a7
a8
2
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
PCM 30 Channel Zero
Multiframe
S
S
S
S
S
F7
A
A
A
A
A
A
A
A
3
0
0
0
0
0
0
0
0
a4
a5
a6
a7
a8
S
S
S
S
S
S
S
S
4
S
S
S
S
S
1
1
1
1
1
1
1
1
F9
a4
a4
a4
a4
a4
a4
a4
a4
a4
a5
a6
a7
a8
S
S
S
S
S
S
S
S
MT9075A
5
1
1
1
1
1
1
1
1
a5
a5
a5
a5
a5
a5
a5
a5
F11 F13 F15
S
S
S
S
S
a4
a5
a6
a7
a8
S
S
S
S
S
S
S
S
6
0
0
0
0
0
0
0
0
a6
a6
a6
a6
a6
a6
a6
a6
S
S
S
S
S
a4
a5
a6
a7
a8
S
S
S
S
S
S
S
S
7
1
1
1
1
1
1
1
1
a7
a7
a7
a7
a7
a7
a7
a7
S
S
S
S
S
4-143
S
S
S
S
S
S
S
S
a4
a5
a6
a7
a8
8
1
1
1
1
1
1
1
1
a8
a8
a8
a8
a8
a8
a8
a8