Static Ram Module; Overview; Functional Description; Static Ram Module Address Map - Motorola M-CORE MMC2001 Series Reference Manual

6.1 Overview

The static RAM (SRAM) module provides 32 Kbytes of general-purpose code and
data storage.

6.2 Functional Description

The 32-Kbyte SRAM module supports byte, halfword, and word accesses with a 32-
bit data interface to the CPU. Only the requested bytes are guaranteed to be valid on
read accesses. The SRAM acknowledges all accesses to its memory space.
Address
30000000
to
30007FFF
30008000
to
3000FFFF
30100000
to
40000000
The SRAM module occupies physical addresses 0x3000 0000 – 0x3000 7FFF. Echo-
ing of the SRAM block occurs throughout the region 0x3000 8000 – 0x300F FFFF; no
attempt is made to detect this condition. Accesses in the range of 0x3010 0000 –
0x3FFF FFFF result in TEA termination to the CPU.
Software designers should be aware that the echoing characteristics of this imple-
mentation may change for future versions of the M•CORE family.
The SPRAM control bit in the EIM configuration register allows selective access pro-
tection to be applied to the RAM. (See 7.7 EIM Configuration Register.) This bit
may be used to control access to the RAM based on the state of the M•CORE
PSR(S) bit. Attempted cycles to a protected RAM address space are terminated with
a TEA response to the CPU.
The SRAM module is partitioned into two independent blocks for the purposes of bat-
tery backup. An external standby power pin is provided to power both sections of the
SRAM for data retention.
The SRAM contents are undefined immediately following a power-on reset.
MMC2001
REFERENCE MANUAL
Freescale Semiconductor, Inc.
SECTION 6

STATIC RAM MODULE

Table 6-1 Static RAM Module Address Map
Use
RAM Array
RAM Echoes on 32-Kbyte Boundaries
Not Used (Access causes transfer error)
STATIC RAM MODULE
For More Information On This Product,
Go to: www.freescale.com
Access
Supervisor,
Selective User
Supervisor,
Selective User
Not Applicable
MOTOROLA
6-1