
Philips Semiconductors
PNX15xx Series
Volume 1 of 1
Chapter 26: Memory Arbiter
PNX15XX_SER_3
Koninklijke Philips Electronics N.V. 2006. All rights reserved.
Product data sheet
Rev. 3 — 17 March 2006
26-4
The combination of these three basic algorithms operate together in the arbiter as
The TDMA timing wheel is implemented with 128 entries, numbered 1 to 128. The
TDMA_entries eld in the NR_entries_A1 register will determine the actual number of
entries that are used. TDMA entries higher than this value will be ignored. If the
TDMA_entries is greater than 128 then all 128 entries are used, but no more. If
TDMA_entries is set to zero then the TDMA timing wheel is not used for arbitration.
The priority list is implemented with 16 entries, numbered 1 to 16. The
Priority_entries eld in the NR_entries_A register will determine the actual number of
entries that are used. If a value greater than 16 is written all 16 entries are used, but
no more. If the Priority_entries is set to zero then the priority list is not used for
arbitration.
The round robin #1 list is implemented with 16 entries, numbered 1 to 16. The
round_robin1_entries
eld in the NR_entries_A register will determine the actual
number of entries that are used. If a value greater than 16 is written all 16 entries are
used, but no more. If the round_robin1_entries is set to zero then the round robin #1 list
is not used for arbitration.
The round robin #2 list is implemented with 8 entries, numbered 1 to 8. The
round_robin2_entries
eld in the NR_entries_A register will determine the actual
number of entries that are used. If a value greater than 8 is written all 8 entries are
used, but no more. If the round_robin2_entries is set to zero then the round robin #2 list
is not used for arbitration.
Figure 1:
Arbitration Scheme
1.
All references to “Set A” registers also apply equally to “Set B”.
TDMA
Timing Wheel
priority list
high
low
round robin #2
overall priority
highest
lowest
round robin #1