Pulse Width Modulation Unit (PWM) (20 MHz)

HOT167-1 Version 2.0Infineon Technologies Corp.June 99

1

FPWMmax =1

28 x 50ns= 78 kHz

Pulse Width Modulation Unit (PWM)(20 MHz)

4 independent PWM channels each with its own time-base• 50ns or 12.8µs timer-resolution provides a very wide frequency range

to generate PWM signals • Programmable output polarity• Up to 78 KHz at 8-bit PWM resolution

Four operation modes• Standard, edge-aligned PWM• Symmetrical, center-aligned PWM for asynchronous motor control• Burst-mode for modulated PWM signals• Single-shot mode


2

PWM unitFrequencies and Resolution

PMW Unit Frequencies and Resolution in Mode 1 Operation (SYMMETRICAL)

PMW Unit Frequencies and Resolution in Mode 0 Operation (EDGE-ALIGNED)

Resolution

Input Clock (CPU @ 20 MHz)

8 Bit 10 Bit 12 Bit 14 Bit 16 Bit

CPU Clock (50ns Resolution)

CPU Clock / 64 (3.2µs Res.)

39.1 KHz

610 Hz

9.77 KHz

152.6 Hz

2.44 KHz

38.15 Hz

610 Hz

9.54 Hz

152.6 Hz

2.4 Hz

Resolution

Input Clock (CPU @ 20 MHz)

8 Bit 10 Bit 12 Bit 14 Bit 16 Bit

CPU Clock (50ns Resolution)

CPU Clock / 64 (3.2µs Res.)

78.1 KHz

1.22 KHz

19.5 KHz

305 Hz

4.88 KHz

76.3 Hz

1.22 KHz

13.1 Hz

305 Hz

4.77 Hz


3

RunEnable

RunEnable

Timer PT0-PT3

Comparator

Shadow Register

INTRINTR Flag Flag INTRINTR

Flag Flag

PWM unitFunction Diagram

InputMode

Control

Pulse Width Reg. PW0-PW3

Shadow Register

4 identical PWM Channels with common Interrupt Control Register

Period Register PP0-PP3

Output PolarityEnable

Output PolarityEnable

20 MHz

78 KHz

at 20 MHz CPU Clock

PWMOutputs

Comparator

up/down,clear


4

PWM unit - Mode 0 and 1

Contents of the PWx Register

Interrupt Request andLatch of the Shadow Register

Contents of the PWxRegister

IR and Latch of theShadow Register

Timer Period

Timer Perio

d Timer Period

Contents of the Period Register (PPx)

PWM Mode 0: Standard PWM’s or Edge-Aligned PWM’s

PWM Mode 1: Symmetrical or Center-Aligned PWM’s

PWM Signal

If all channels are programmed to mode 0,edge-aligned PWM signals will be generated.A duty cycle from 0 to 100% is programmable

If all channels are programmed to mode 1,center-aligned PWM signals will be generated.A duty cycle from 0 to 100% is programmable

PWM Signal

Possible PWM Signals from other channels programmed to the same mode:

PWMx

PWMy


5

PWM unit - Burst Mode / Single Shot Mode

Burst Mode :Burst Sequence by combiningPWM channel 0 and 1

Single Shot : Only one PWM Pulse is generated Mode available for channel 2 and 3

Period Value Period Value

Pulse widthValue

PeriodValue

Internal Signalof Channel 0

Period ofTimer PT1

Int. Signalof Channel 1

Output Result: Channel 1 is modulated by Channel 0

OutputSignal

Timer isautomatically

stopped

Timer isreleased by

Software again

The Timer can be dynamically changed tolengthen (retrigger) or shorten the output pulse

Tim

er Perio

d

Timer Period PT0


6

Overview Port Structure

The Port lines provide the connection to the external world• 111 Port lines on the C167

All Port lines are individually addressable and all I/0 lines are independently programmable for input or output

Each Port line is dedicated to one or more peripheral functions Each Port is protected with fast diodes Programmable open drain buffers

• P2, 3, 6, 7, 8 on the C167


7

DirectionRegister

OutputLatch

AlternateOutput

AlternateEnable

Read Direction

Write

ClockAlternate Input

Inte

rnal

Bu

s

Overview Port Structure

Buffer

Mux

Mux

Buffer

InputLatch

Open DrainControl

VCC

Vss

Port Pin

ESD structure


8

Exercise 7PWM_1 - Two edge-alignedPWM Signals with the PWM unit

Objective:• Generate an edge-aligned 25% duty cycle PWM Signal using PWM

channel 1 (Period: 1ms)• Generate an edge-aligned 50% duty cycle PWM Signal using PWM

channel 3 (Period: 1ms)


9

* C167CS not yet supported by DAvE V1.0 CD ROM. See “Hints regarding DAvE.”

Exercise 7PWM_1- DAvE Configurations

Start DAvE Create new Project with microcontroller C167CR/CS*

• Project name: 7pwm_1• Select project path: c:\hot167_1\7pwm_1

Project Settings:• General:

- Select Keil Compiler, SMALL model • System Clock:

- External Oscillator Frequency: Set to 5 MHz• Startup Configuration:

- Bus Type after Reset: Set to 16 bit DEMUX- Write Configuration: Pin #WR and #BHE operates as #WRL and

#WRH• Save & close


10

Exercise 7PWM_1 - DAvE Configurations (cont.)

Configure PWM:• Control:

- Configure Channel 1:- General: Use PWM Channel 1- PWM Channel Mode Control: Standard PWM (edge aligned)- Channel Output Enable: Enable Channel 1 output signal- PWM Timer Start Control: Start PWM Timer 1 after init- Period: Required Period: 1000 us- Duty Cycle: Required Duty Cycle: 25%- Save & Close

- Configure Channel 3:- General: Use PWM Channel 3- PWM Channel Mode Control: Standard PWM (edge aligned)- Channel Output Enable: Enable Channel 3 output signal- PWM Timer Start Control: Start PWM Timer 3 after init- Period: Required Period: 1000 us- Duty Cycle: Required Duty Cycle: 50%- Save & Close


11


Configure PWM (cont.)• Functions:

- Include PWM initialization function PWM_vInit• Save & Close

Configure Port 7:• Port 7:

- DAvE has reserved P7.1 and P7.3 for the PWM alternate functions with 0 as initial output

- Don’t enable general purpose IO!• Functions:

- Include port initialization function IO_vInit• Save & close

Generate Code


12

Exercise 7PWM_1 - µVision2 Configurations

Start µVision2 New Project Add Files:

• Go to Project | Targets, Groups, Files…• Click ‘Groups / Add Files’• Select ‘Source Group 1’• Click ‘Add Files to Group’• Select all C files and click ‘add’• Enter file name ‘start.asm’, click ‘add’ (Assembler Startup File)• Click ‘Close’ and ‘OK’• Double-click all files in the Project Window to open them

Select Target Hardware (kitCON-167):• Go to Project | Options for Target ‘Target 1’• Go to ‘Debug’ tab• Click ‘Settings’ (upper right hand corner)• Monitor configuration: select ‘Phytec KC167’• Click ‘OK’ twice


13

Exercise 7PWM_1 -µVision2 Configurations (cont.)

Edit MAIN.C:• include endless loop in main():

// USER CODE BEGIN (Main,2)

while(1) {};

// USER CODE END


14

Exercise 7PWM_1 - Running the Program

Reset Target Hardware (Press Reset Button on Starter Kit)

Build Project (Project | Rebuild Target) Run integrated Debugger from within µVision2

• Debug | Start / Stop Debug Session (click ‘OK’ when prompted)• The Debugger will load the Keil Monitor into the kitCON-167’s RAM

via bootstrap loader• Object file c:\hot167_1\7pwm_1\7pwm_1 will be loaded automatically

and the debugger will go to main(). Go! (Debug | Go)

Program Verification: Connect Scope to• P7.1 / POUT1 (connector X3 pin 121)• P7.3 / POUT3 (connector X3 pin 122)


15

Exercise 7PWM_2 - Two center-alignedPWM Signals with the PWM unit

Objective: • Generate a center-aligned 25% duty cycle PWM Signal using PWM

channel 1 (Period: 250 us)• Generate a center-aligned 50% duty cycle PWM Signal using PWM

channel 3 (Period: 250us)


16

* C167CS not yet supported by DAvE V1.0 CD ROM. See “Hints regarding DAvE.”

Exercise 7PWM_2 - DAvE Configurations

Start DAvE Create new Project with microcontroller C167CR/CS*

• Project name: 7pwm_2• Select project path: c:\hot167_1\7pwm_2

Project Settings:• General:

- Select Keil Compiler, SMALL model • System Clock:

- External Oscillator Frequency: Set to 5 MHz• Startup Configuration:

- Bus Type after Reset: Set to 16 bit DEMUX- Write Configuration: Pin #WR and #BHE operates as #WRL and

#WRH• Save & close


17


Configure PWM:• Control:

- Configure Channel 1:- General: Use PWM Channel 1- PWM Channel Mode Control: Symmetrical PWM

(center aligned)- Channel Output Enable: Enable Channel 1 output signal- PWM Timer Start Control: Start PWM Timer 1 after init- Period: Required Period: 250 us- Duty Cycle: Required Duty Cycle: 25%- Save & Close

- Configure Channel 3:- General: Use PWM Channel 3- PWM Channel Mode Control: Symmetrical PWM

(center aligned)- Channel Output Enable: Enable Channel 3 output signal- PWM Timer Start Control: Start PWM Timer 3 after init- Period: Required Period: 250 us- Duty Cycle: Required Duty Cycle: 50%- Save & Close


18


Configure PWM (cont.)• Functions:

- Include PWM initialization function PWM_vInit• Save & Close

Configure Port 7:• Port 7:

- DAvE has reserved P7.1 and P7.3 for the PWM alternate functions with 0 as initial output

• Functions:- Include port initialization function IO_vInit

• Save & close

Generate Code


19

Exercise 7PWM_2 - µVision2 Configurations

Start µVision2 Open Project c:\hot167_1\7pwm_1\7pwm_1.uv2 (Project | Open Pr.) Add Files:

• Go to Project | Targets, Groups, Files…• Click ‘Groups / Add Files’• Select ‘Source Group 1’• Click ‘Add Files to Group’• Select all C files and click ‘add’• Enter file name ‘start.asm’, click ‘add’ (Assembler Startup File)• Click ‘Close’ and ‘OK’• Double-click all files in the Project Window to open them

Select Target Hardware (kitCON-167):• Go to Project | Options for Target ‘Target 1’• Go to ‘Debug’ tab• Click ‘Settings’ (upper right hand corner)• Monitor configuration: select ‘Phytec KC167’• Click ‘OK’ twice


20

Exercise 7PWM_2 -µVision2 Configurations (cont.)

Edit MAIN.C:• include endless loop in main():

// USER CODE BEGIN (Main,2)

while(1) {};

// USER CODE END


21

Exercise 7PWM_2 - Running the Program

Reset Target Hardware (Press Reset Button on Starter Kit)

Build Project (Project | Rebuild Target) Run integrated Debugger from within µVision2

• Debug | Start / Stop Debug Session (click ‘OK’ when prompted)• The Debugger will load the Keil Monitor into the kitCON-167’s RAM

via bootstrap loader• Object file c:\hot167_1\7pwm_1\7pwm_1 will be loaded automatically

and the debugger will go to main(). Go! (Debug | Go)

Program Verification: Connect Scope to• P7.1 / POUT2 (connector X3 pin 121)• P7.3 / POUT4 (connector X3 pin 123)

Documents

Pulse Width Modulation Unit (PWM) (20 MHz)