
Philips Semiconductors
PNX15xx Series
Volume 1 of 1
Chapter 29: Endian Mode
PNX15XX_SER_3
Koninklijke Philips Electronics N.V. 2006. All rights reserved.
Product data sheet
Rev. 3 — 17 March 2006
29-12
6.2.2
Address Invariant Data Ordering Rules
The address invariance rule of the DTL interface is given in
Table 6. A given byte lane
implies the address, regardless of endian mode of the system.
Modules dealing with 8, 16 or 32-bit units must place bytes on the DTL interface given
6.3 Data Transfers Across the DCS Network
The DCS Network is said to be “endian neutral”. Although this bus is intended to
transfer mainly 32-bits of control and status data, it can carry smaller units of data
(8-bit, 16-bit for e.g., CPU accesses to PCI devices). Accesses on this bus are mainly
MMIO accesses. The only memory accesses allowed are for booting purposes via
the DCS Gate module. This is only accessed by the boot module. The DCS Network
is not designed for DMA burst transfers.
Modules that transfer smaller data items (8- or 16-bit) must observe the packing rules
Table 6: 32 Bit DTL Interface Byte Address
DTL-D[31:24]
DTL-D[23:16]
DTL-D[15:8]
DTL-D[7:0]
4n+3
4n+2
4n+1
4n+0
Table 7: DTL Interface Rules
Module
Item Unit
Size
System
Endian Mode
DTL_D[31:24]
DTL_D[23:16]
DTL_D[15:8]
DTL_D[7:0]
8 bits
either
item #4 with
address a+3
item #3 with
address a+2
item #2 with
address a+1
item #1 with
address a
16 bits
big
item #2 with address a+2
item #1 with address a
bits 7..0
bits 15..8
bits 7..0
bits 15..8
16 bits
little
item #2 with address a+2
item #1 with address a
bits 15..8
bits 7..0
bits 15..8
bits 7..0
32 bits
big
item with address a
bits 7..0
bits 15..8
bits 23..16
bits 31..24
32 bits
little
item with address a
bits 31..24
bits 23..16
bits 15..8
bits 7..0
Table 8: DCS Network Data Transfer Rules (32 Bits at-a-time Transfer)
Module
Item Unit
Size
System
Endian Mode
DCS_D[31:24]
DCS_D[23:16]
DCS_D[15:8]
DCS_D[7:0]
8 bits
big
item #1 with
address a
item #2 with
address a+1
item #3 with
address a+2
item #4 with
address a+3
8 bits
little
item #4 with
address a+3
item #3 with
address a+2
item #2 with
address a+1
item #1 with
address a