Datasheet

ARMulator Reference

width

is the width of the data bus in bytes (that is, 1 for an 8-bit bus, 2 for a

16-bit bus, or 4 for a 32-bit bus).

access

describes the type of accesses that can be performed on this region of

memory:

for read-only.

for write-only.

for read-write.

for no access. Any access causes a Data or Prefetch Abort.

An asterisk (*) can be appended to

access

to describe a Thumb-based

system that uses a 32-bit data bus to memory, but which has a 16-bit latch

to latch the upper 16 bits of data, so that a subsequent 16-bit sequential

access can be fetched directly out of the latch.

read-times

describes the nonsequential and sequential read times in nanoseconds.

These must be entered as the nonsequential read access time followed by

a slash ( / ), followed by the sequential read access time. Omitting the

slash and using only one figure indicates that the nonsequential and

sequential access times are the same.

NoteNote

For accurate modelling of real devices, you might have to add a signal

propagation delay (20 to 30ns) to the read and write times quoted for a

memory chip.

write-times

describes the nonsequential and sequential write times. The format is the

same as that given for read times.

The following examples assume a clock speed of 20MHz, the default.

Example 1

0 80000000 RAM 4 rw 135/85 135/85

This describes a system with a single continuous section of RAM from

0x7FFFFFFF

with a 32-bit data bus, read-write access, nonsequential access time of 135ns, and

sequential access time of 85ns.