
Overview
MOTOROLA
ColdFire2/2M User’s Manual
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1.3.2.6 ROM ARRAY.
critical code, and monitor code. It is connected directly to the ColdFire2/2M via a dedicated
bus. Refer to
Section 5.3 ROM Module
for more information on the ROM configuration and
the interface signals.
The optional ROM array is a compiled ROM used to hold boot code,
1.3.2.7 SLAVE MODULES.
communicate with the ColdFire2/2M via the slave bus and SBC. Slave modules are always
bus slaves and cannot initiate bus transactions except via interrupts. Examples of slave
modules include serial ports, parallel ports, and timers.
The slave modules are on-chip peripherals. They
1.3.2.8 SRAM ARRAY.
variables and the stack. It is connected directly to the ColdFire2/2M processor via a
dedicated bus. Refer to
Section 5.4 SRAM Module
configuration and the interface signals.
The optional SRAM array is a compiled RAM used to hold critical
for more information on the SRAM
1.3.2.9 SYSTEM BUS CONTROLLER (SBC).
providing overall control of the slave and external busses. The system bus controller is the
single slave-bus master and interrupt controller, a possible external bus master, bus arbiter
and interrupt controller, and a master-bus slave and interrupt controller. The SBC provides
programmable registers to configure the memory map and interrupt control. The SBC
provides master bus cycle termination for accesses to slave modules on the slave bus. It
also generates interrupts on the master bus when requested by slaves on the slave bus, and
it responds to interrupt acknowledge cycles on the master bus.
The system bus controller is responsible for
1.4 PROGRAMMING MODEL
The ColdFire2/2M programming model consists of three register groups: integer unit user,
MAC unit user, and supervisor. Programs executing in the user mode use only the registers
in the integer and MAC groups. System software executing in the supervisor mode can
access all registers and use the control registers in the supervisor group to perform
supervisor functions. The following paragraphs provide a brief description of the registers in
the user and supervisor models. Refer to
Appendix A Register Summary
.
1.4.1 Integer Unit User Programming Model
Figure 1-5
illustrates the integer portion of the user programming model. It consists of the
following registers:
16 general-purpose 32-bit registers (D0 – D7, A0 – A7)
32-bit Program Counter (PC)
8-bit Condition Code Register (CCR)
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