tools/validation/startupdelay/main.c

   1 /**************************************************************************/
   2 /*!
   3     @file     main.c
   4     @author   K. Townsend (microBuilder.eu)
   5
   6     @section LICENSE
   7
   8     Software License Agreement (BSD License)
   9
  10     Copyright (c) 2011, microBuilder SARL
  11     All rights reserved.
  12
  13     Redistribution and use in source and binary forms, with or without
  14     modification, are permitted provided that the following conditions are met:
  15     1. Redistributions of source code must retain the above copyright
  16     notice, this list of conditions and the following disclaimer.
  17     2. Redistributions in binary form must reproduce the above copyright
  18     notice, this list of conditions and the following disclaimer in the
  19     documentation and/or other materials provided with the distribution.
  20     3. Neither the name of the copyright holders nor the
  21     names of its contributors may be used to endorse or promote products
  22     derived from this software without specific prior written permission.
  23
  24     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ''AS IS'' AND ANY
  25     EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  26     WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  27     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY
  28     DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  29     (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  30     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  31     ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  32     (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  33     SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  34 */
  35 /**************************************************************************/
  36 #include "projectconfig.h"
  37
  38 #include "core/gpio/gpio.h"
  39
  40 /**************************************************************************/
  41 /*!
  42     As soon as the chip comes out of reset and the startup code has
  43     finished executing, sets up GPIO pin 2.1 as an ouput and high.
  44
  45     This can be used to determine the startup delay, by measuring the
  46     time between reset be deasserted and the GPIO pin going high, minus
  47     the GPIO overhead of a few clock cycles.
  48
  49     HW Setup: Set channel one of the oscilliscope to the reset pin, and
  50               channel two of the oscilliscope to GPIO pin 2.1.
  51
  52               Set a trigger on the rising edge of the reset pin, and
  53               measure the delay between the rising edge of reset and the
  54               rising edge of GPIO 2.1.
  55 */
  56 /**************************************************************************/
  57 int main(void)
  58 {
  59   /* Enable AHB clock to the GPIO domain. */
  60   SCB_SYSAHBCLKCTRL |= (SCB_SYSAHBCLKCTRL_GPIO);
  61
  62   /* Set 2.1 to output and high */
  63   GPIO_GPIO2DIR  |= (1 << 1);    // pin 1 = Output
  64   GPIO_GPIO2DATA |= (1 << 1);    // pin 1 = High
  65
  66   while(1)
  67   {
  68   }
  69
  70   return 0;
  71 }