
MC68F375
OVERVIEW DESCRIPTION
MOTOROLA
REFERENCE MANUAL
Rev. 25 June 03
1-9
1.7 Address Map
Each MC68300/MC68HC16 derivative MCU has a 4-Kbyte block in the memory map
that is assigned to internal module registers. The MSB of the block address is user-
programmable via the MM (MODMAP) bit in the SCIMMCR register, see 1.7.1 to the individual modules, as shown in the MC68F375 address map in Figure 1-2.
These sub-blocks vary in size, depending on the register requirements for each mod-
ule. Positioning of registers within the module sub-blocks is dependent on the
individual modules and is specified in the respective module specifications. The RAM,
ROM, and CMFI array spaces are not shown with an assigned address because the
arrays are not enabled after reset. The arrays are enabled and the base address is set
by writing to the control blocks of each array.
Each module that is assigned a sub-block is responsible for responding to any
accesses within its assigned address range. Modules do not respond to any register
address within the module address space which is not implemented and not reserved.
These addresses are mapped outside the MC68F375. An access to a register at an
address which is reserved returns zeros, as do accesses to reserved bits within
registers.
If the SUPV bit in the module configuration register (MCR) within a module is set, any
user mode accesses to the module are mapped externally.
1.7.1 Address Bus Decoding
The internal MODMAP line is compared to internal address line A[23] while A[22:0] are
decoded by each module. If a module control block address is decoded, the access
will be internal. The value of A[22] down to the module block size is defined in Figure 1-2 for each module. These bits are fixed for this particular derivative device and are
specified by Motorola. The value of MODMAP is specified by the MM control bit in the
Power (VDDH, VDDL, VSS)
I/O Pad Power (VDDH)
Logic Power (VDDL)
Ground (VSS)
SRAM (VSTBY)
DPTRAM (VDDDPTRAM)
CMFI (VPP)
SCIM2E Clock (VDDSYN/VSSSYN)
QADC64 Power (VDDA/VSSA)
QADC64 Reference (VRH/VRL)
Total
14
3
16
1
2
42
Total
199
114
Table 1-1 MC68F375 Pin Usage (Continued)
Functions
Total Pins
Port Pins
F
re
e
sc
a
le
S
e
m
ic
o
n
d
u
c
to
r,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
n
c
..
.