peb20550 Infineon Technologies Corporation, peb20550 Datasheet - Page 191

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

The value written to MADR should have the following format:
4 bit C/I value: MADR = 1 1 _ _ _ _ 1 1
6 bit SIG value: MADR = _ _ _ _ _ _ 1 1
8 bit SIG value: MADR = _ _ _ _ _ _ _ _
Examples
In CFI mode 0 the downstream time slots 6 and 7 of port 2 shall be initialized as MF and
CS channels, 6 bit signaling scheme. The initialization value shall be ‘010101’:
W:MADR
W:MAAR
W:MACR
W:MADR
W:MAAR
W:MACR
The above programming sequence can for example be performed during the
initialization phase of the EPIC. Once the CFI time slots have been loaded with the
appropriate codes ('1010' in time slot 6 and ‘1011’ in time slot 7), an access to the
downstream SIG channel (time slot 7) can be accomplished simply by writing a new
value to the address of time slot 6:
W:MADR
W:MAAR
W:MACR
5.5.2.3 Access to the Upstream C/I and SIG Channels
If two consecutive upstream CFI time slots, starting with an even time slot number, are
programmed as MF and CS channels, the P can read the received 4, 6 or 8 bit C/I or
SIG values simply by reading the upstream CM data field.
Two cases can be distinguished:
When a 4 bit Command/Indication handling scheme is selected, the C/I value received
in the odd CFI time slot can be read from the even CM address. This value is sampled
in each frame (every 125 s). Each change is furthermore indicated by an ISTA:SFI
interrupt and the address of the corresponding even CM location is stored in the CIFIFO.
Since the MSB of the CIFIFO is set to 1 for a valid entry (SBV = 1), the value read from
the CIFIFO can directly be copied to MAAR in order to read the upstream CM data field
which also requires an MSB set to 1 (U/D = 1).
When a 6 or 8 bit signaling scheme is selected, the received SIG value is sampled at
intervals of 125 s or (TVAL + 1)
CM address. The P can access the actual value simply by reading this even CM data
field location. Additionally, a “stable value”, based on the double last look algorithm is
generated: in order to assure that erroneous bit changes at the sampling time point do
Semiconductor Group
= 0101 0111
= 0001 1100
= 0111 1010
= XXXX XXXX
= 0001 1101
= 0111 1011
= 1100 1111
= 0001 1100
= 0100 1000
B
B
B
B
B
B
B
B
B
; SIG value ‘010101’
; downstream, port 2, time slot 6
; write CM code + data fields, CM code ‘1010’
; don’t care
; downstream, port 2, time slot 7
; write CM code + data fields, CM code ‘1011’
; new SIG value ‘110011’
; downstream, port 2, time slot 6
; write CM DF, MOC = 1001
250 s and stored as the “actual value” at the even
B
B
B
191
Application Hints
PEB 2055
PEF 2055