tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC176X/sleep.c

   1 /* mbed Microcontroller Library
   2  * Copyright (c) 2006-2013 ARM Limited
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 #include "sleep_api.h"
  17 #include "cmsis.h"
  18 #include "mbed_interface.h"
  19
  20 void sleep(void) {
  21
  22 #if (DEVICE_SEMIHOST == 1)
  23     // ensure debug is disconnected
  24     mbed_interface_disconnect();
  25 #endif
  26
  27     // PCON[PD] set to sleep
  28     LPC_SC->PCON = 0x0;
  29
  30     // SRC[SLEEPDEEP] set to 0 = sleep
  31     SCB->SCR &= ~SCB_SCR_SLEEPDEEP_Msk;
  32
  33     // wait for interrupt
  34     __WFI();
  35 }
  36
  37 /*
  38 * The mbed lpc1768 does not support the deepsleep mode
  39 * as a debugger is connected to it (the mbed interface).
  40 *
  41 * As mentionned in an application note from NXP:
  42 *
  43 *       http://www.po-star.com/public/uploads/20120319123122_141.pdf
  44 *
  45 *       {{{
  46 *       The user should be aware of certain limitations during debugging.
  47 *       The most important is that, due to limitations of the Cortex-M3
  48 *       integration, the LPC17xx cannot wake up in the usual manner from
  49 *       Deep Sleep and Power-down modes. It is recommended not to use these
  50 *       modes during debug. Once an application is downloaded via JTAG/SWD
  51 *       interface, the USB to SWD/JTAG debug adapter (Keil ULINK2 for example)
  52 *       should be removed from the target board, and thereafter, power cycle
  53 *       the LPC17xx to allow wake-up from deep sleep and power-down modes
  54 *       }}}
  55 *
  56 *       As the interface firmware does not reset the target when a
  57 *       mbed_interface_disconnect() semihosting call is made, the
  58 *       core cannot wake-up from deepsleep.
  59 *
  60 *       We treat a deepsleep() as a normal sleep().
  61 */
  62
  63 void deepsleep(void) {
  64
  65 #if (DEVICE_SEMIHOST == 1)
  66     // ensure debug is disconnected
  67     mbed_interface_disconnect();
  68 #endif
  69
  70     // PCON[PD] set to deepsleep
  71     sleep();
  72 }