SCTimer/PWM

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Introduction
The patent-pending State Controlled Timer (SCTimer/PWM) is a sophisticated, yet easy-to-configure timer that delivers unprecedented flexibility, enabling engineers to future-proof their designs and reduce time-to-market. In its simplest configuration, it gives designers more timers or more high-resolution Pulse Width Modulators (PWMs) with a resolution of <1ns. It also lets designers configure advanced timing operations, including those required for complex motor-control functions, while meeting tight development schedules.

The SCT is a timer-capture unit coupled with a highly-flexible, event-driven state machine. It brings two familiar concepts — event and state — to the area of timing, thus enabling a wide variety of operations for timing, counting, output modulation, and input capture. It is an X-input, X-output timer system with match/capture registers, events, and states. It can be configured as two 16-bit timers or as a single 32-bit timer.

By combining a timer array with a state machine, the SCTimer/PWM enables complex functionality, including event-controlled PWM waveform generation, ADC synchronization, and dead-time control without CPU intervention. It simplifies the design of user-defined waveforms and control signals in a wide range of applications including power conversion, lighting, motor control, and audio applications.

The SCTimer/PWM is available on all NXP's Cortex-Mx microcontroller series.
SCTimer/PWM resources for each family:

NXP Part

inputs

outputs

states

events

match /

capture

SCTIPU

dithering

SCTPLL

LPC81x 

4

4

2

6

5

No

No

No

LPC82x

4

6

8

8

8

No

No

No

LPC11U6x/E6x – SCT0/1

4

4

8

6

5

No

No

No

LPC15xx – SCT0/1 

8

10

16

16

16

Yes

Yes

Yes

LPC15xx – SCT2/3

3

6

10

10

8

Yes

No

No

LPC18/43xx (flashless)

8

16

32

16

16

No

No

No

LPC18/43xx (flash)

8

16

32

16

16

No

Yes

No

LPC54xxx

8

8

13

13

13

No

Yes

No

 

 

 

 

 

 

 

 

 

 

 

 

 

Summary

  •     SCTimer/PWM provides more timers, high resolution PWMs, and the ability to generate complex waveforms
  •     SCTimer/PWM is a sophisticated, yet easy-to-configure timer
  •     SCTimer/PWM is a programmable and flexible peripheral
  •     SCTimer/PWM allows engineers to future-proof their designs
  •     SCTimer/PWM reduces time-to-market by removing design complexity
  •     SCTimer/PWM off-loads CPU bandwidth; Once programmed, it functions independently from the CPU core


Operation

  


Tools


LPCXpresso

The Red State SCTimer/PWM state machine generator is included in LPCXpresso and supports the SCT in all targets.

lpcxpresso-support's picture 

 

http://www.lpcware.com/lpcxpresso/download 

 

SCT Tool
This tool supports code examples for the LPC1800 and LPC4300 series.

SCT Tools (for LPC18xx State Configurable Timer) using Windows V2.0 (Jul 8, 2011)

http://www.lpcware.com/content/nxpfile/an11161-using-sct-lpcxpresso-keil-and-iar-software 


Example code
The SCTimer/PWM Cookbook and Tutorial contains many useful examples, including standard PWMs, PWM with dead-time, RC5 encoder and decoder, and many others. Each example is presented in such a way that features are incrementally introduced, so it can also be used as a tutorial.
The download below includes a detailed documentation and source code for each example.

DOWNLOAD THE SCTimer/PWM COOKBOOK HERE

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