peb20550 Infineon Technologies Corporation, peb20550 Datasheet - Page 98

• Manufacturer Part Number: peb20550
• Description: Extended Pcm Interface Controller
• Manufacturer: Infineon Technologies Corporation

The PCM interface shall be clocked with a PDC having twice the frequency of the data
rate i.e. 6144 kHz. Since the rising edge of PFS occurs a little bit before the rising edge
of PDC i.e. the set-up and hold times with respect to the rising PDC are met, it is possible
to select the rising PDC edge for sampling the PFS signal (PMOD:PSM = 1). In this case
the 1st bit of the internal framing structure (according to figure 27) will represent time
slot 47, bit 1 (383rd bit) in upstream and time slot 0, bit 5 (3rd bit) in downstream direction
of the external frame (according to figure 25). The values to be programmed to the
POFD, POFD and PCSR can now be determined as follows:
With BND = 3, BNU = 383 and BPF = 384:
OFD9 … 1 = (BND – 33 + BPF)
OFU9 … 1 = (BNU + 47)
POFD = 1011 0001
POFU = 1000 1111
With URE = 1 and DRE = 1:
PCSR = 0001 0001
PCM Receive Line Selection PMOD:AIS1 … AIS0
The PCM transmit line of a given logical port (as it is used for programming the switching
function) is always assigned to a dedicated physical transmit pin, e.g. in PCM mode 1,
pin TxD2 carries the PCM data of logical port 1.
In receive direction however, an assignment between logical and physical ports can be
made in PCM modes 1 and 2. This selection is programmed via the Alternative Input
Selection bits 1 and 0 (AIS1, AIS0) in the PMOD register.
In PCM mode 0, AIS1 and AIS0 should both be set to 0.
In PCM mode 1, AIS0 selects between receive lines RxD0 and RxD1 for logical port 0
and AIS1 between the receive lines RxD2 and RxD3 for logical port 1.
In PCM mode 2, AIS1 selects between the receive lines RxD2 and RxD3, the setting of
AIS0 is don’t care.
The state of the AIS# bits is furthermore put out via the TSC# pins and can thus be used
to control external circuits (drivers, relays … ).
Semiconductor Group
B
B
B
= B1
= 17
= 11
mod BPF
H
H
H
,
,
= (383 + 47)
mod BPF
= (3 – 33 + 384)
98
mod 384
= 46
D
mod 384
= 0001 0111 0
= 354
D
= 1 0110 0010
Application Hints
B
PEB 2055
PEF 2055
B