User's Manual
152 www.xilinx.com PowerPC™ 405 Processor Block Reference Guide
1-800-255-7778 UG018 (v2.0) August 20, 2004
Chapter 3: PowerPC 405 OCM Controller
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Figure 3-6 shows the extended feature in Virtex-4 for DSOCM-to-Memory-Mapped-Slave-
Peripheral interface.
ISOCM Ports 
Figure 3-7 and Figure 3-8 are block diagrams of the ISOCM in Virtex-II Pro and Virtex-4. 
All signals are in big endian format.
Figure 3-6: DSOCM to Memory-Mapped Slave Peripheral (Virtex-4 Extended Feature)
DSOCMBRAMEN
UG018_37c_042304
DSOCMBRAMABUS[8:29]
Virtex-4 Processor Block
DSOCMBRAMWRDBUS[0:31]
DSOCMBRAMBYTEWRITE[0:3]
BRAMDSOCMRDDBUS[0:31]
DSOCMRDADDRVALID
DSOCMWRADDRVALID
DSOCMRDWRCOMPLETE
BRAMDSOCMCLK
Data-Side
On-Chip Memory 
(DSOCM) Controller
Memory Mapped
OCM Slave 
(Variable Latency)
Figure 3-7: ISOCM Interface for Virtex-II Pro
ISOCMBRAMEN
ISOCMBRAMODDWRITEEN
UG018_38_020102
RESET
ISOCMBRAMRDABUS[8:28]
BRAMISOCMRDDBUS[0:63]
ISOCMBRAMWRABUS[8:28]
ISOCMBRAMWRDBUS[0:31]
BRAMISOCMCLK
CPMC405CLOCK
ISCNTLVALUE[0:7]
ISARCVALUE[0:7]
TIEISOCMDCRADDR[0:7]
ISOCMBRAMEVENWRITEEN
Clock & Reset are 
same signals that go 
into CPU; therefore, 
no separate Clock & 
Reset are required.
Instruction-Side
On-Chip Memory 
(ISOCM) Controller










