MC145572AC Freescale Semiconductor, MC145572AC Datasheet - Page 143

• Manufacturer Part Number: MC145572AC
• Manufacturer: Freescale Semiconductor

Specifications of MC145572AC

• Number Of Line Interfaces: 1
• Control Interface: HDLC
• Lead Free Status / Rohs Status: Compliant

MOTOROLA
8.5
8.6
GCI MASTER AND SLAVE MODE OPERATION
The MC145572 can be configured for GCI master or GCI slave operation independently of LT or NT
configuration. When the pin M/S is pulled low to V SS, GCI slave operation is selected. When the pin
M/S is pulled high to V DD , GCI master operation is selected. When configured as a slave, FSC is
an input driven by external circuitry. FSC must be synchronized to the clock applied to DCL. When
configured as a master, the MC145572 drives FSC as an output.
U-INTERFACE SUPERFRAME ALIGNMENT
The MC145572 uses the FSC signal to indicate superframe alignment. In LT mode as a GCI slave,
the FSC pin is used to force alignment of the transmitted U–interface superframe. Normally, the FSC
pulse is two DCL clocks in duration. Alignment of the transmitted superframe can be forced by driving
FSC with a one DCL clock wide pulse, once every 96 GCI frames. The 2B+D data read into the D in
pin following the single clock wide FSC, corresponds to the first 2B+D transmitted onto the U–inter-
face. If superframe alignment is not input to FSC, the MC145572 aligns the outgoing U–interface
superframe.
When configured for master mode and either LT or NT operation, reception of the first 2B+D data
from the U–interface superframe is indicated by the MC145572 outputting a FSC pulse that is one
DCL clock wide. This happens once every 96 GCI frames.
In NT mode, IDL2 slave operation, any superframe alignment information that may be present on
FSC is ignored. ANSI T1.601 defines when the NT transmitted superframe occurs with respect to
the received superframe.
If FSC is to be used to set the alignment of the transmitted superframe in LT mode, it must
be stable prior to activating the MC145572.
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
MC145572
WARNING
8–19