le75282 Zarlink Semiconductor, le75282 Datasheet - Page 14

• Manufacturer Part Number: le75282
• Description: Dual Intelligent Line Card Access Switch
• Manufacturer: Zarlink Semiconductor

APPLICATIONS
Figure 6, on page 16
There are numerous ways to control the Le75282 LCAS device using the P1’-P3’/LDx and OFFx inputs. A one-to-one wiring of
SLAC P1 to LCAS P1’, SLAC P2 to LCAS P2’, and SLAC P3 to LCAS P3’, is usually not the desired connection. When using the
Le79Q224x/Le79228 SLAC as the controller, wiring of the control port varies dependent upon the desired operating states. P1,
P2, and P3 control lines are used to control the ISLIC device and the LCAS device. When LDx is high, the P-bus controls the
operating states of the ISLIC via C1, C2, and C3. When LDx is low, the P-bus controls the relay drivers and the test load in the
ISLIC device as well as the operating states of the LCAS device via RD1, RD2, and RD3. So functionality between the ISLIC
device and the LCAS device needs to be coordinated in order to provide the desired performance.
Control and wiring scenarios for the ISLIC device and LCAS device follows.
The following LCAS operating state options are available through P-bus control:
Note, for all five states, the All Off operating state can be asserted by driving the OFFx pin Low.
For option 1, LCAS CFG = 0 and LCAS P3’ = 0, wire SLAC P1 to LCAS P2’, and wire SLAC P3 to LCAS P1’, do not wire SLAC
P2 to the LCAS. The test load (if enabled) can then be applied independent of the LCAS operating state. When SLAC P1 = 1, the
Ringing and Test/Monitor state will be activated when the external ringing signal is at zero cross (assuming CCR4 RMODE is set
for external ringing (1) and ZXR is set for enable zero cross ringing relay operation (0)). For the Ringing state this is the desired
operation. For the Test/Monitor state, the delay in activation needs to be considered in the firmware.
For option 2, LCAS CFG = 0 or 1 and LCAS P3’ = 1, wire SLAC P1 to LCAS P2’, and wire SLAC P3 to LCAS P1’, do not wire
SLAC P2 to the LCAS. The test load (if enabled) can then be applied independent of the LCAS operating state. When SLAC P1
= 1, the Ringing and Test Ringing state will be activated when the external ringing signal is at zero cross (assuming CCR4 RMODE
is set for external ringing (1) and ZXR is set for enable zero cross ringing relay operation (0)). This is desired operation.
1. Idle/Talk, Ringing, Test, Test/Monitor
2. Idle/Talk, Ringing, Test/Monitor, Test Ringing
3. Idle/Talk, Ringing, Test, All Off
4. Idle/Talk, Ringing, Test, Test/Monitor, Test Ringing
5. Idle/Talk, Ringing, Test, Test/Monitor, Test Ringing, All Off
Active High Battery
Test (Load) Switch
Active Low Battery
R1 (Relay Driver)
Standby (scan)
illustrates the internal functionality of the Le75282 device.
Disconnect
TIP Open
Le79232 ISLIC
OHT
Le75282 LCAS
Control
Switch
D
E
C
O
D
E
R
Figure 5. ISLIC Device and LCAS Control
C
1
C
2
C
3
R
D
1
R
D
2
R
D
R
D
2
R
D
3
1
VCC
VDD
D
E
M
U
X
L
A
T
C
H
Zarlink Semiconductor Inc.
LD1
P2
P3
P1'
P2'
P3'
P1
LD1
Re-wiring as
Connections are shown for channel one only
necessary
14
RD1-RD3 controlled by SLAC I/O Register
LD1
P1
P2
P3
Le79228
SLAC