AN2866 Freescale Semiconductor / Motorola, AN2866 Datasheet - Page 6

• Manufacturer Part Number: AN2866
• Description: Migrating from the MC68332 to the ColdFire MCF523x
• Manufacturer: Freescale Semiconductor / Motorola

Device Differences
2.1.3
One of the primary advantages of migrating to the MCF523x is the significant increase in performance and
frequency. Whereas the MC68332 has a Dhrystone 2.1 MIPS rating of approximately 7.5 MIPS when
running at 25 MHz, the MCF523x offers approximately 24 MIPS of performance at the same frequency.
That is, the MCF523x offers over a 3x performance boost without changing the frequency. Moreover, the
MCF523x can provide 144 MIPS performance at its maximum frequency of 150 MHz.
2.1.4
Unlike the MC68332, the MCF523x has a 32-bit external data bus. In order to maintain as much
compatibility as possible with the MC68332, customers can choose to operate the MCF523x in a 16-bit
data bus mode. At reset, if the boot port width is configured for an 8- or 16-bit port, then only the upper
half of the data bus (D[31:16]) will be configured for data bus functionality; the lower half of the 32-bit
data bus (D[15:0]) will default to GPIO pin functions. The lower data bus pins can be enabled as data bus
pins later if needed.
2.2
With the trend toward miniaturization, smaller, lighter, and higher performance products have paved the
way for smaller component packages and higher pin counts. For this reason, the Mold Array Process-Ball
Grid Array (MAPBGA) is used as the production package for the MCF523x. It is a surface mount package
that uses solder balls arranged in a grid array instead of the lead pins normally used in Quad Flat Pack
(QFP) and other packages. The MCF523x’s 256-pin and 196-pin MAPBGA packages give it many
advantages over a QFP. For compatibility, the MCF5232 is also available in a 160-pin QFP; however, it is
the only member of the MCF523x family available in a QFP package.
6
Mechanical Characteristics
Figure 2. Buffering Scheme for Isolating 5V Memories and Peripherals on a 3.3V Bus
Frequency and Performance
Operating the MCF523x in 16-bit Data Bus Mode
MCF523x
Migrating from the MC68332 to the ColdFire
SDRAM
®
MCF523x, Rev. 1.0
3.3V Devices
5V Devices
Freescale Semiconductor