User guide

DC 900-1338I 51
Chapter
3
Memory Organization
This chapter describes the memory maps for the ICP2424, ICP2432, and ICP6000.
3.1 ICP2424
The 128-kilobyte EPROM on the ICP2424 is located at address 0x0000. The EPROM
contains the diagnostics, Peeker debugging tool, and boot loader.
One megabyte of dynamic random access memory (DRAM) starts at 0x00800000. This
DRAM is only accessible to the MC68340 and is used for program and private data
space that does not need to be accessed by any of the devices in the Z-bus space. The
Z-bus space contains one megabyte of DRAM as shared memory. The shared memory
starts at 0x01000000 as seen from the MC68340. The shared memory is to buffer data
between the ISAbus and the IUSCs. The ISAbus has access to that memory at the loca-
tions defined in Ta ble 3 –1. The IUSCs’ DMA controllers see the shared memory at
0x00000000.
Addresses 0x00800000 to 0x00801200 of the private memory are reserved. The system
services module (containing the operating systems and XIO) is loaded beginning at
address 0x00801200. As described in Section 4.3.1 on page 75, the fixed memory
requirements for a particular version of the system services module are specified in the
spsdefs.h file, and additional memory required for the OS/Impact’s configurable data
section depends on the system configuration. The rest of the DRAM is available for user
applications.