MT90710
required. This is implemented using an external 8x8
static RAM (35 ns). Only 256 bytes are used of the
8K total. RAM address and data (FBADDR0-7 and
FBDATA0-7) signals are generated along with an
output enable strobe (FBOE) and a write enable
strobe (FBWE).
ST-BUS Interface
Preliminary Information
The first nine STo7 channels are reserved for
overhead information:
STo7 Channel
0
1
2
3
4
5
6
7
8
Function
not available
not available
Reserved
Local error count
(most significant byte)
Local error count
(least significant byte)
Reserved
Remote error count
(most significant byte)
Remote error count
(least significant byte)
synchronization detect
(see STo7 channel 8 definition)
Mode # Mode 2 Mode 1 Mode 0
0
1
2
3
4
5
6
7
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
ST6MUX
Configuration
ENABLED CONTROLLER
ENABLED
not used
PERIPHERAL
not used
DISABLED CONTROLLER
not used
not used
not used
DISABLED
not used
not used
not used
PERIPHERAL
Table 1 - Operational Mode Select
STo7 Channel 8 Definition:
B7
B6
Fiber Interface
Eight of the 256 fiber channels are reserved for
overhead information. These are fiber channels:
Channel #
Function
0
Frame Alignment
8
Asynchronous signal transfer and
synchronization detect
16
Checksum of previous frame
24
Reserved
32
Reserved
40
Reserved
48
Remote error count most significant byte
56
Remote error count least significant byte
B5, B4, B3
B2, B1, B0
remote receiver is in frame synch
when logic 1
Local receiver is in frame synch
when logic 1
Reserved
Reserved
Overhead Information
ST6MUX
ST-BUS to Fiber
When ST6MUX is enabled the STi6A and STi6B
input streams are alternately multiplexed onto the
fiber link. (i.e., only half of the bandwidth of each link
is utilized). The transmit pattern at the fiber interface
is:
STi6A-Chan0,STi6B-Chan1,STi6A-Chan2,STi6B-Chan3,...,
STi6B-Chan29,STi6A-Chan30,STi6B-Chan31
Multiplexed Stream
STo6A Data from STi6A
STo6B Data from STi6B
Chan 0
Chan 0
Chan 1
Chan 1
Chan 0
Chan 1
Chan 2
Chan 2
Chan 3
Chan 3
Chan 2
Chan 3
Chan 4
Chan 4
Chan 5
Chan 5
Chan 4
Chan 5
.....
.....
.....
Chan 28
Chan 28
Chan 29
Chan 29
Chan 28
Chan 29
Chan 30
Chan 30
Chan 31
Chan 31
Chan 30
Chan 31
Table 2 - ST6MUX Channel Assignment
5-10
MITEL [ MITEL NETWORKS CORPORATION ]
