mc68ez328 Freescale Semiconductor, Inc, mc68ez328 Datasheet - Page 4

• Manufacturer Part Number: mc68ez328
• Description: Integrated Portable System Processor
• Manufacturer: Freescale Semiconductor, Inc

System Configuration
2
The MC68EZ328 system integration module (SIM28-EZ) consists of several functions that control the
system start-up, initialization, configuration, and the external bus with a minimum of external devices. The
memory interface allows the user to interface gluelessly with the widely available SRAM and EPROM as
well as FLASH memory. With the assistance of chip-select logic, wait states can be programmable. The
interrupt controller accepts and resolves the priority from internal modules and external generated
interrupts. It also handles the masking and wake-up selection control for power control. The low-power
logic can be used to control the CPU power dissipation by altering the frequency or stopping the CPU. In
addition, the SIM28-EZ is capable of configuring the pin to allow the user to select either dedicated I/O or
parallel I/O. This feature help to increase the number of available I/O ports by reclaiming when the
dedicated function is not used.
2.1
The MC68EZ328 system configuration logic consists of a system control register (SCR) which allows the
user to configure operation of the following major functions:
2.2
The clock synthesizer can operate with either an external crystal or an external oscillator for reference,
using the internal phase-locked loop (PLL) and voltage-controlled oscillator (VCO), or an external clock
can directly drive the clock signal at the operating frequency.
2.3
The MC68EZ328 provides eight programmable general purpose chip-select signals. For a given chip-
select block, the user may choose whether the chip-select allows read-only, or both read and write
accesses, whether a DTACK is automatically generated for this chip-select, and after how many wait states
(from zero to six) the DTACK will be generated.
2.4
The external bus interface handles the transfer of information between the internal 68EC000 core and the
memory, peripherals, or other processing elements in the external address space. It consists of a 16 bit
68000 bus interface for internal and a 8 bit interface to outside.
2.5
The interrupt controller accepts and prioritizes both internal and external interrupt requests and generates a
vector number during the CPU interrupt acknowledge cycle. Interrupt nesting is also provided so that an
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System Status and Control Logic
Bus Error Generation Control
Protect module control registers from access by user programs
System Integration Module
System Configuration
VCO/PLL Clock Synthesizer
Chip Select Logic
External Bus Interface
Interrupt Controller
MC68EZ328 Product Brief