Introduction
MOTOROLA
MC68360 USER’S MANUAL
1-7
Because of the similarity of the QUICC SIM60 and CPU to other members of the M68300
family, such as the MC68332 and the MC68340, previous users of these devices will be
comfortable with these same features on the QUICC.
1.3.2 Hardware Compatibility Issues
The following list summarizes the hardware differences between the MC68302 and the
QUICC:
Pinout—The pinout is not the same. The QUICC has 240 pins; the MC68302 has 132
pins.
Package—Both devices offer PGA and PQFP packages. However, the QUICC
PQFP package has a 20-mil pitch; whereas, the MC68302 PQFP package has a
25-mil pitch.
System Bus—The system bus signals now look like those of the MC68030 as opposed
to those of the M68000. It is still possible to interface M68000 peripherals to the QUICC,
utilizing the same techniques used to interface them to an MC68020 or MC68030.
System Bus in Slave Mode—A number of QUICC pins take on new functionality in slave
mode to support an external MC68EC040. On the MC68302, the pin names generally
remained the same in slave mode.
Peripheral Timing—The external timings of the peripherals (SCCs, timers, etc.) are very
similar (if not identical) to corresponding peripherals on the MC68302.
Pin Assignments—The assignment of peripheral functions to I/O pins is different in sev-
eral ways. First, the QUICC contains more general-purpose parallel I/O pins than the
MC68302. However, the QUICC offers many more functions than even a 240-pin pack-
age would normally allow, resulting in more multifunctional pins than the MC68302.
1.3.3 Software Compatibility Issues
The following list summarizes the major software differences between the MC68302 and the
QUICC:
Since the CPU32+ is a superset of the M68000 instruction set, all previously written
code will run. However, if such code is accessing the MC68302 peripherals, it will re-
quire some modification.
The QUICC contains an 8-Kbyte block of memory as opposed to a 4-Kbyte block
on the MC68302. The register addresses within that memory map are different.
The code used to initialize the system integration features of the MC68302 has
to be modified to write the corresponding features on the QUICC SIM60. Code written
for the MC68340 may be adapted in large part.
As much as possible, QUICC CPM features were made identical to those of the
MC68302 CP. The most important benefit is that the code flow (if not the code itself) will
port easily from the MC68302 to the QUICC. The nuances learned from the MC68302
will still be useful in the QUICC.
Although the registers used to initialize the QUICC CPM are new (for example, the SCM
on the MC68302 is replaced with the GSMR and PSMR on the QUICC), most registers
retain their original purpose such as the SCC event, SCC mask, SCC status, and com-