MOTOROLA
Chip-Select Module
10-1
Section 10
Chip-Select Module
10.1
INTRODUCTION
The Chip Select Module provides user-programmable control of the four chip select outputs, two buffer
enable outputs and one output-enable signal.
This section describes the operation and programming model of the chip-select (CS) registers, including
the chip select address, mask, and control registers.
10.1.1
CHIP SELECT FEATURES
Four programmable chip select signals
IORDY and TA handshake pins
Two programmable buffers enable signals for glueless interface to bus buffers
Address masking for memory block sizes from 64KBytes to 4GBytes
Programmable wait states
Port size is 16 bits
10.2
CHIP-SELECT SIGNALS
The MCF5249 provides four programmable chip selects that can directly interface with SRAM, EPROM,
EEPROM, and peripherals. Two of these chip selects are usable for AT-bus peripherals that need
separate read and write strobe, and use IORDY signalling to insert wait states.
10.2.1
CHIP SELECTS
10.2.1.1 CS0
CS0 is the first chip select and it addresses the boot memory. (A ROM or flash memory device.) At
power-on reset, all bus cycles are mapped to the CS0. This allows the boot memory to be defined at any
address space. CS0 is the only chip select initialized at reset.
10.2.1.2 CS1/GPIO1
CS1 is the second chip select and it can be programmed for an address location as well as for masking,
port size and burst capability indication, wait state generation, and internal/external termination. A reset
clears all chip select programming
10.2.1.3 CS2/IDE-DIOR/GPIO13 AND IDE-DIOW/GPIO14
These two signals go active during CS2 cycles. IDE-DIOR can be programmed to go active on read and
write cycles, or IDE-DIOR can be programmed to go active only on read cycles, and IDE-DIOW only on
write cycles. It has identical features as the normal CS2. It can be programmed for an address location as
well as for masking, port size and burst capability indication, wait state generation, and internal/external
termination.
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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