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Memory Maps
8.2.8
Address Decoding with the 21555
The 21555 implements multiple base address registers on both the primary and secondary
interfaces that denote separate address ranges for both downstream and upstream
transactions. It also has base registers for access to its Control and Status Register (CSR)
space. Consequently, on the primary interface (CompactPCI bus) the 21555 responds only to
those transactions which are in the address range defined by one of the base address ranges.
All other addresses are ignored. The same is true for transactions on the secondary interface
(local PCI bus).
The address ranges defined by the primary base address registers reside in the primary or
system address map. The address ranges defined by the secondary base address registers
reside in the secondary or local address map. Each of these address maps is independent of
each other. The 21555 provides address translation between these two address maps when
forwarding transactions upstream or downstream.
Recommendations for CompactPCI mapping can be found in the MCPN905 CompactPCI
Single Board Computer Programmer's Reference Guide (MCPN905A/PG).
8.2.9
L1, L2 and L3 Cache
The CPCI-6115 supports the MPC7457 processor on-chip L1 and L2 caches with 2 MB of
external L3 cache installed. The CPCI-6115 L3 memory consists of two 8 megabit (256Kx36,
300 MHz, 1.9 ns access) devices providing a total of 2 MB of memory. Data parity checking
should be enabled. The following settings assume a processor speed of 1000 MHz and L3 clock
speed of 200 MHz.
Table 8-6 Apollo L3CR Register Assignments
Apollo L3CR
Register
L3SIZ
L3RT
L3PE
L3CLK
L3CKSP
L3PSP
Refer to the PowerPC
information (Addendum to SC-Vger Book IV Version - 1.0 04/21/00).
8.2.10
System Memory
The CPCI-6115 system memory capability is controlled through an I
controller integrated into the MV64360 system controller.
130
Description
L3 size, 1 MB
L3 SRAM type, DDR SRAM
L3 data parity checking enable, on
L3 Clk speed; 266 MHz, divide by 5
L3 clock sample point, 4 clocks
L3 P-clock sample point, 3 clocks
™
Apollo Microprocessor Implementation Definition Book IV for more
CPCI-6115 CompactPCI Single Board Computer Installation and Use (6806800A68D)
Address Decoding with the 21555
Value
0b
00b
1b
111b
10b
011b
2
C compatible serial
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