Freescale MC56F8257数字信号控制器开发方案

• Parallel instruction set with unique DSP addressing modes

• Hardware DO and REP loops

• Instruction set supports DSP and controller functions

• Controller-style addressing modes and instructions for compact code

• Efficient C compiler and local variable support

• Software subroutine and interrupt stack with depth limited only by memory

•JTAG/enhanced on-chip emulation (EOnCE) for unobtrusive, processor speed–independent, real-time debugging

Operation Range

• 3.0 V to 3.6 V operation (power supplies and I/O)

• From power-on-reset: approximately 2.7 V to 3.6 V

• Ambient temperature operating range: –40 ℃ to +105 ℃

Memory

• Dual Harvard architecture that permits as many as three simultaneous accesses to program and data memory

• 48 KB (24K x 16) to 64 KB (32K x 16) on-chip flash memory with 2048 bytes (1024 x 16) page size

• 6 KB (3K x 16) to 8 KB (4K x 16) on-chip RAM with byte addressable

• EEPROM emulation capability using flash

• Support for 60 MHz program execution from both internal flash and RAM memories

• Flash security and protection that prevent unauthorized users from gaining access to the internal flash

Interrupt Controller

• Five interrupt priority levels

— Three user programmable priority levels for each interrupt source: Level 0, 1, 2

— Unmaskable level 3 interrupts include: illegal instruction, hardware stack overflow, misaligned data access, and SWI3 instruction Maskable level 3 interrupts include: EOnCE step counter, EOnCE breakpoint unit, and EOnCE trace buffer

— Lowest-priority software interrupt: level LP

• Nested interrupts: higher priority level interrupt request can interrupt lower priority interrupt subroutine

• Two programmable fast interrupts that can be assigned to any interrupt source

• Notification to system integration module (SIM) to restart clock out of wait and stop states

• Ability to relocate interrupt vector table

The masking of interrupt priority level is managed by the 56800E core.

Peripheral Highlights

• One Enhanced Flex Pulse Width Modulator (eFlexPWM) module

— Up to nine output channels

— 16-bit resolution for center aligned, edge aligned, and asymmetrical PWMs

— Each complementary pair can operate with its own PWM frequency based and deadtime values

– 4 Time base

– Independent top and bottom deadtime insertion

— PWM outputs can operate as complimentary pairs or independent channels

— Independent control of both edges of each PWM output

— 6-channel NanoEdge high resolution PWM

– Fractional delay for enhanced resolution of the PWM period and edge placement

– Arbitrary eFlexPWM edge placement - PWM phase shifting

– NanoEdge implementation: 520 ps PWM frequency resolution

— 3 Channel PWM with full Input Capture features

– Three PWM Channels - PWMA, PWMB, and PWMX

– Enhanced input capture functionality

— Support for synchronization to external hardware or other PWM

— Double buffered PWM registers

– Integral reload rates from 1 to 16

– Half cycle reload capability

— Multiple output trigger events can be generated per PWM cycle via hardware

— Support for double switching PWM outputs

— Up to four fault inputs can be assigned to control multiple PWM outputs

– Programmable filters for fault inputs

— Independently programmable PWM output polarity

— Individual software control for each PWM output

— All outputs can be programmed to change simultaneously via a FORCE_OUT event

— PWMX pin can optionally output a third PWM signal from each submodule

— Channels not used for PWM generation can be used for buffered output compare functions

— Channels not used for PWM generation can be used for input capture functions

— Enhanced dual edge capture functionality

— Option to supply the source for each complementary PWM signal pair from any of the following:

– Crossbar module outputs

– External ADC input, taking into account values set in ADC high and low limit registers

• Two independent 12-bit analog-to-digital converters (ADCs)

— 2 x 8 channel external inputs Built-in x1, x2, x4 programmable gain pre-amplifier

— Maximum ADC clock frequency: up to 10 MHz

– Single conversion time of 8.5 ADC clock cycles (8.5 x 100 ns = 850 ns)