/********************************************************************** * $Id$ abstract.txt *//** * @file abstract.txt * @brief Example description file * @version 2.0 * @date * @author NXP MCU SW Application Team * * Copyright(C) 2010, NXP Semiconductor * All rights reserved. * *********************************************************************** * Software that is described herein is for illustrative purposes only * which provides customers with programming information regarding the * products. This software is supplied "AS IS" without any warranties. * NXP Semiconductors assumes no responsibility or liability for the * use of the software, conveys no license or title under any patent, * copyright, or mask work right to the product. NXP Semiconductors * reserves the right to make changes in the software without * notification. NXP Semiconductors also make no representation or * warranty that such application will be suitable for the specified * use without further testing or modification. **********************************************************************/ @Example description: Purpose: This example describes how to use Timer to measure a signal's frequency. Process: 1) Initialize UART0 and display information menu. 2) Ask user to input frequency for a test signal. Configure P1.26 as CAP0.0, P0.6 as MAT2.0. 3) Configure TIMER2 as follow: - Prescale register = 1 us. - Match register = 1 / ((frequency)*1us*2) = 500000 / freuqency - No interrupt, no stop but reset timer counter on match. Configure TIMER0 as follow: - Prescale register = 1 us. - Capture register: channel 0, capture on rising edge, generate interrupt on capture. 4) Configure TIMER0 ISR: - Prepare 5 interrupt times, in which timer counter and prescale are reset, for stable. - After this 5 interrupt times, get the capture value, raise done flag. 5) Start TIMER0 and TIMER2. Wait for done flag, then calculate and print out the measure frequency by: one cycle = capture value * 1us (as TIMER0 configuration). signal frequency = 1/one cycle = 1,000,000 / capture value. Press c if we intend to test with other frequencies. TIMER0 and TIMER2 are de-initialized. @Directory contents: \EWARM: includes EWARM (IAR) project and configuration files \Keil: includes RVMDK (Keil)project and configuration files lpc17xx_libcfg.h: Library configuration file - include needed driver library for this example makefile: Example's makefile (to build with GNU toolchain) freqmeasure.c: Main program @How to run: Hardware configuration: Serial display configuration: (e.g: TeraTerm, Hyperterminal, Flash Magic...) – 115200bps – 8 data bit – No parity – 1 stop bit – No flow control Running mode: This example can run on RAM/ROM mode. (Please reference "LPC1000 Software Development Toolchain" - chapter 4 "Creating and working with LPC1000CMSIS project" for more information) Step to run: - Step 1: Build example. - Step 2: Burn hex file into board (if run on ROM mode) - Step 3: Connect COM1 on the Lincoln board to COM port on your computer - Step 4: Configure hardware and serial display as above instruction - Step 5: Run example Use a wire connect J2 pin 5 (P0.6) and J2 pin 17 (P1.26) Use PC's terminal to select the test signal on P1.26 and see the result measured frequency printed out. (Pls see "LPC17xx Example Description" document - chapter "Examples > TIMER > FreqMeasure" for more details) @Tip: - Open \EWARM\*.eww project file to run example on IAR - Open \RVMDK\*.uvproj project file to run example on Keil