From b0f0d2e9ca18d8604225bed3c984e4cf1b4c4b3c Mon Sep 17 00:00:00 2001 From: Dimitri Sokolyuk Date: Wed, 10 Feb 2016 20:31:09 +0100 Subject: Initial import --- Libraries/CMSIS/Documentation/CMSIS_Core.htm | 1337 ++++++++++++++++++++++++++ 1 file changed, 1337 insertions(+) create mode 100644 Libraries/CMSIS/Documentation/CMSIS_Core.htm (limited to 'Libraries/CMSIS/Documentation/CMSIS_Core.htm') diff --git a/Libraries/CMSIS/Documentation/CMSIS_Core.htm b/Libraries/CMSIS/Documentation/CMSIS_Core.htm new file mode 100644 index 0000000..6fd131e --- /dev/null +++ b/Libraries/CMSIS/Documentation/CMSIS_Core.htm @@ -0,0 +1,1337 @@ + + + + CMSIS: Cortex Microcontroller Software Interface Standard + + + +

Cortex Microcontroller Software Interface Standard

+ +

This file describes the Cortex Microcontroller Software Interface Standard (CMSIS).

+

Version: 1.30 - 30. October 2009

+ +

Information in this file, the accompany manuals, and software is
+ Copyright © ARM Ltd.
All rights reserved. +

+ +
+ +

Revision History

+ + +
+ +

Contents

+ +
    +
  1. About
  2. +
  3. Coding Rules and Conventions
  4. +
  5. CMSIS Files
  6. +
  7. Core Peripheral Access Layer
  8. +
  9. CMSIS Example
  10. +
+ +

About

+ +

+ The Cortex Microcontroller Software Interface Standard (CMSIS) answers the challenges + that are faced when software components are deployed to physical microcontroller devices based on a + Cortex-M0 or Cortex-M3 processor. The CMSIS will be also expanded to future Cortex-M + processor cores (the term Cortex-M is used to indicate that). The CMSIS is defined in close co-operation + with various silicon and software vendors and provides a common approach to interface to peripherals, + real-time operating systems, and middleware components. +

+ +

ARM provides as part of the CMSIS the following software layers that are +available for various compiler implementations:

+ + +

These software layers are expanded by Silicon partners with:

+ + +

CMSIS defines for a Cortex-M Microcontroller System:

+ + +

+ By using CMSIS compliant software components, the user can easier re-use template code. + CMSIS is intended to enable the combination of software components from multiple middleware vendors. +

+ +

Coding Rules and Conventions

+ +

+ The following section describes the coding rules and conventions used in the CMSIS + implementation. It contains also information about data types and version number information. +

+ +

Essentials

+ + +

Recommendations

+ +

The CMSIS recommends the following conventions for identifiers.

+ + +Comments + + + +

Data Types and IO Type Qualifiers

+ +

+ The Cortex-M HAL uses the standard types from the standard ANSI C header file + <stdint.h>. IO Type Qualifiers are used to specify the access + to peripheral variables. IO Type Qualifiers are indented to be used for automatic generation of + debug information of peripheral registers. +

+ + + + + + + + + + + + + + + + + + + + + + + + +
IO Type Qualifier#defineDescription
__Ivolatile constRead access only
__OvolatileWrite access only
__IOvolatileRead and write access
+ +

CMSIS Version Number

+

+ File core_cm3.h contains the version number of the CMSIS with the following define: +

+ +
+#define __CM3_CMSIS_VERSION_MAIN  (0x01)      /* [31:16] main version       */
+#define __CM3_CMSIS_VERSION_SUB   (0x30)      /* [15:0]  sub version        */
+#define __CM3_CMSIS_VERSION       ((__CM3_CMSIS_VERSION_MAIN << 16) | __CM3_CMSIS_VERSION_SUB)
+ +

+ File core_cm0.h contains the version number of the CMSIS with the following define: +

+ +
+#define __CM0_CMSIS_VERSION_MAIN  (0x01)      /* [31:16] main version       */
+#define __CM0_CMSIS_VERSION_SUB   (0x30)      /* [15:0]  sub version        */
+#define __CM0_CMSIS_VERSION       ((__CM0_CMSIS_VERSION_MAIN << 16) | __CM0_CMSIS_VERSION_SUB)
+ + +

CMSIS Cortex Core

+

+ File core_cm3.h contains the type of the CMSIS Cortex-M with the following define: +

+ +
+#define __CORTEX_M                (0x03)
+ +

+ File core_cm0.h contains the type of the CMSIS Cortex-M with the following define: +

+ +
+#define __CORTEX_M                (0x00)
+ + +

CMSIS Files

+

+ This section describes the Files provided in context with the CMSIS to access the Cortex-M + hardware and peripherals. +

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
FileProviderDescription
device.hDevice specific (provided by silicon partner)Defines the peripherals for the actual device. The file may use + several other include files to define the peripherals of the actual device.
core_cm0.hARM (for RealView ARMCC, IAR, and GNU GCC)Defines the core peripherals for the Cortex-M0 CPU and core peripherals.
core_cm3.hARM (for RealView ARMCC, IAR, and GNU GCC)Defines the core peripherals for the Cortex-M3 CPU and core peripherals.
core_cm0.cARM (for RealView ARMCC, IAR, and GNU GCC)Provides helper functions that access core registers.
core_cm3.cARM (for RealView ARMCC, IAR, and GNU GCC)Provides helper functions that access core registers.
startup_deviceARM (adapted by compiler partner / silicon partner)Provides the Cortex-M startup code and the complete (device specific) Interrupt Vector Table
system_deviceARM (adapted by silicon partner)Provides a device specific configuration file for the device. It configures the device initializes + typically the oscillator (PLL) that is part of the microcontroller device
+ +

device.h

+ +

+ The file device.h is provided by the silicon vendor and is the + central include file that the application programmer is using in + the C source code. This file contains: +

+ + + +

Interrupt Number Definition

+ +

To access the device specific interrupts the device.h file defines IRQn +numbers for the complete device using a enum typedef as shown below:

+
+typedef enum IRQn
+{
+/******  Cortex-M3 Processor Exceptions/Interrupt Numbers ************************************************/
+  NonMaskableInt_IRQn             = -14,      /*!< 2 Non Maskable Interrupt                              */
+  HardFault_IRQn                  = -13,      /*!< 3 Cortex-M3 Hard Fault Interrupt                      */
+  MemoryManagement_IRQn           = -12,      /*!< 4 Cortex-M3 Memory Management Interrupt               */
+  BusFault_IRQn                   = -11,      /*!< 5 Cortex-M3 Bus Fault Interrupt                       */
+  UsageFault_IRQn                 = -10,      /*!< 6 Cortex-M3 Usage Fault Interrupt                     */
+  SVCall_IRQn                     = -5,       /*!< 11 Cortex-M3 SV Call Interrupt                        */
+  DebugMonitor_IRQn               = -4,       /*!< 12 Cortex-M3 Debug Monitor Interrupt                  */
+  PendSV_IRQn                     = -2,       /*!< 14 Cortex-M3 Pend SV Interrupt                        */
+  SysTick_IRQn                    = -1,       /*!< 15 Cortex-M3 System Tick Interrupt                    */
+/******  STM32 specific Interrupt Numbers ****************************************************************/
+  WWDG_STM_IRQn                   = 0,        /*!< Window WatchDog Interrupt                             */
+  PVD_STM_IRQn                    = 1,        /*!< PVD through EXTI Line detection Interrupt             */
+  :
+  :
+  } IRQn_Type;
+ + +

Configuration for core_cm0.h / core_cm3.h

+

+ The Cortex-M core configuration options which are defined for each device implementation. Some + configuration options are reflected in the CMSIS layer using the #define settings described below. +

+

+ To access core peripherals file device.h includes file core_cm0.h / core_cm3.h. + Several features in core_cm0.h / core_cm3.h are configured by the following defines that must be + defined before #include <core_cm0.h> / #include <core_cm3.h> + preprocessor command. +

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
#defineFileValueDescription
__NVIC_PRIO_BITScore_cm0.h(2)Number of priority bits implemented in the NVIC (device specific)
__NVIC_PRIO_BITScore_cm3.h(2 ... 8)Number of priority bits implemented in the NVIC (device specific)
__MPU_PRESENTcore_cm0.h, core_cm3.h(0, 1)Defines if an MPU is present or not
__Vendor_SysTickConfigcore_cm0.h, core_cm3.h(1)When this define is setup to 1, the SysTickConfig function + in core_cm3.h is excluded. In this case the device.h + file must contain a vendor specific implementation of this function.
+ + +

Device Peripheral Access Layer

+

+ Each peripheral uses a prefix which consists of <device abbreviation>_ + and <peripheral name>_ to identify peripheral registers that access this + specific peripheral. The intention of this is to avoid name collisions caused + due to short names. If more than one peripheral of the same type exists, + identifiers have a postfix (digit or letter). For example: +

+ + +
Minimal Requiements
+

+ To access the peripheral registers and related function in a device the files device.h + and core_cm0.h / core_cm3.h defines as a minimum: +

+ + +

+ These definitions allow to access the peripheral registers from user code with simple assignments like: +

+
SysTick->CTRL = 0;
+ +
Optional Features
+

In addition the device.h file may define:

+ + +

core_cm0.h and core_cm0.c

+

+ File core_cm0.h describes the data structures for the Cortex-M0 core peripherals and does + the address mapping of this structures. It also provides basic access to the Cortex-M0 core registers + and core peripherals with efficient functions (defined as static inline). +

+

+ File core_cm0.c defines several helper functions that access processor registers. +

+

Together these files implement the Core Peripheral Access Layer for a Cortex-M0.

+ +

core_cm3.h and core_cm3.c

+

+ File core_cm3.h describes the data structures for the Cortex-M3 core peripherals and does + the address mapping of this structures. It also provides basic access to the Cortex-M3 core registers + and core peripherals with efficient functions (defined as static inline). +

+

+ File core_cm3.c defines several helper functions that access processor registers. +

+

Together these files implement the Core Peripheral Access Layer for a Cortex-M3.

+ +

startup_device

+

+ A template file for startup_device is provided by ARM for each supported + compiler. It is adapted by the silicon vendor to include interrupt vectors for all device specific + interrupt handlers. Each interrupt handler is defined as weak function + to an dummy handler. Therefore the interrupt handler can be directly used in application software + without any requirements to adapt the startup_device file. +

+

+ The following exception names are fixed and define the start of the vector table for a Cortex-M0: +

+
+__Vectors       DCD     __initial_sp              ; Top of Stack
+                DCD     Reset_Handler             ; Reset Handler
+                DCD     NMI_Handler               ; NMI Handler
+                DCD     HardFault_Handler         ; Hard Fault Handler
+                DCD     0                         ; Reserved
+                DCD     0                         ; Reserved
+                DCD     0                         ; Reserved
+                DCD     0                         ; Reserved
+                DCD     0                         ; Reserved
+                DCD     0                         ; Reserved
+                DCD     0                         ; Reserved
+                DCD     SVC_Handler               ; SVCall Handler
+                DCD     0                         ; Reserved
+                DCD     0                         ; Reserved
+                DCD     PendSV_Handler            ; PendSV Handler
+                DCD     SysTick_Handler           ; SysTick Handler
+ +

+ The following exception names are fixed and define the start of the vector table for a Cortex-M3: +

+
+__Vectors       DCD     __initial_sp              ; Top of Stack
+                DCD     Reset_Handler             ; Reset Handler
+                DCD     NMI_Handler               ; NMI Handler
+                DCD     HardFault_Handler         ; Hard Fault Handler
+                DCD     MemManage_Handler         ; MPU Fault Handler
+                DCD     BusFault_Handler          ; Bus Fault Handler
+                DCD     UsageFault_Handler        ; Usage Fault Handler
+                DCD     0                         ; Reserved
+                DCD     0                         ; Reserved
+                DCD     0                         ; Reserved
+                DCD     0                         ; Reserved
+                DCD     SVC_Handler               ; SVCall Handler
+                DCD     DebugMon_Handler          ; Debug Monitor Handler
+                DCD     0                         ; Reserved
+                DCD     PendSV_Handler            ; PendSV Handler
+                DCD     SysTick_Handler           ; SysTick Handler
+ +

+ In the following examples for device specific interrupts are shown: +

+
+; External Interrupts
+                DCD     WWDG_IRQHandler           ; Window Watchdog
+                DCD     PVD_IRQHandler            ; PVD through EXTI Line detect
+                DCD     TAMPER_IRQHandler         ; Tamper
+ +

+ Device specific interrupts must have a dummy function that can be overwritten in user code. + Below is an example for this dummy function. +

+
+Default_Handler PROC
+                EXPORT WWDG_IRQHandler   [WEAK]
+                EXPORT PVD_IRQHandler    [WEAK]
+                EXPORT TAMPER_IRQHandler [WEAK]
+                :
+                :
+                WWDG_IRQHandler
+                PVD_IRQHandler
+                TAMPER_IRQHandler
+                :
+                :
+                B .
+                ENDP
+ +

+ The user application may simply define an interrupt handler function by using the handler name + as shown below. +

+
+void WWDG_IRQHandler(void)
+{
+  :
+  :
+}
+ + +

system_device.c

+

+ A template file for system_device.c is provided by ARM but adapted by + the silicon vendor to match their actual device. As a minimum requirement + this file must provide a device specific system configuration function and a global variable + that contains the system frequency. It configures the device and initializes typically the + oscillator (PLL) that is part of the microcontroller device. +

+

+ The file system_device.c must provide + as a minimum requirement the SystemInit function as shown below. +

+ + + + + + + + + + + + + + + + +
Function DefinitionDescription
void SystemInit (void)Setup the microcontroller system. Typically this function configures the + oscillator (PLL) that is part of the microcontroller device. For systems + with variable clock speed it also updates the variable SystemCoreClock.
+ SystemInit is called from startup_device file.
void SystemCoreClockUpdate (void)Updates the variable SystemCoreClock and must be called whenever the + core clock is changed during program execution. SystemCoreClockUpdate() + evaluates the clock register settings and calculates the current core clock. +
+ +

+ Also part of the file system_device.c + is the variable SystemCoreClock which contains the current CPU clock speed shown below. +

+ + + + + + + + + + + + +
Variable DefinitionDescription
uint32_t SystemCoreClockContains the system core clock (which is the system clock frequency supplied + to the SysTick timer and the processor core clock). This variable can be + used by the user application to setup the SysTick timer or configure other + parameters. It may also be used by debugger to query the frequency of the + debug timer or configure the trace clock speed.
+ SystemCoreClock is initialized with a correct predefined value.

+ The compiler must be configured to avoid the removal of this variable in + case that the application program is not using it. It is important for + debug systems that the variable is physically present in memory so that + it can be examined to configure the debugger.
+ +

Note

+ + + +

Core Peripheral Access Layer

+ +

Cortex-M Core Register Access

+

+ The following functions are defined in core_cm0.h / core_cm3.h + and provide access to Cortex-M core registers. +

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
Function DefinitionCoreCore RegisterDescription
void __enable_irq (void)M0, M3PRIMASK = 0Global Interrupt enable (using the instruction CPSIE + i)
void __disable_irq (void)M0, M3PRIMASK = 1Global Interrupt disable (using the instruction + CPSID i)
void __set_PRIMASK (uint32_t value)M0, M3PRIMASK = valueAssign value to Priority Mask Register (using the instruction + MSR)
uint32_t __get_PRIMASK (void)M0, M3return PRIMASKReturn Priority Mask Register (using the instruction + MRS)
void __enable_fault_irq (void)M3FAULTMASK = 0Global Fault exception and Interrupt enable (using the + instruction CPSIE + f)
void __disable_fault_irq (void)M3FAULTMASK = 1Global Fault exception and Interrupt disable (using the + instruction CPSID f)
void __set_FAULTMASK (uint32_t value)M3FAULTMASK = valueAssign value to Fault Mask Register (using the instruction + MSR)
uint32_t __get_FAULTMASK (void)M3return FAULTMASKReturn Fault Mask Register (using the instruction MRS)
void __set_BASEPRI (uint32_t value)M3BASEPRI = valueSet Base Priority (using the instruction MSR)
uiuint32_t __get_BASEPRI (void)M3return BASEPRIReturn Base Priority (using the instruction MRS)
void __set_CONTROL (uint32_t value)M0, M3CONTROL = valueSet CONTROL register value (using the instruction MSR)
uint32_t __get_CONTROL (void)M0, M3return CONTROLReturn Control Register Value (using the instruction + MRS)
void __set_PSP (uint32_t TopOfProcStack)M0, M3PSP = TopOfProcStackSet Process Stack Pointer value (using the instruction + MSR)
uint32_t __get_PSP (void)M0, M3return PSPReturn Process Stack Pointer (using the instruction MRS)
void __set_MSP (uint32_t TopOfMainStack)M0, M3MSP = TopOfMainStackSet Main Stack Pointer (using the instruction MSR)
uint32_t __get_MSP (void)M0, M3return MSPReturn Main Stack Pointer (using the instruction MRS)
+ +

Cortex-M Instruction Access

+

+ The following functions are defined in core_cm0.h / core_cm3.hand + generate specific Cortex-M instructions. The functions are implemented in the file + core_cm0.c / core_cm3.c. +

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
NameCoreGenerated CPU InstructionDescription
void __NOP (void)M0, M3NOPNo Operation
void __WFI (void)M0, M3WFIWait for Interrupt
void __WFE (void)M0, M3WFEWait for Event
void __SEV (void)M0, M3SEVSet Event
void __ISB (void)M0, M3ISBInstruction Synchronization Barrier
void __DSB (void)M0, M3DSBData Synchronization Barrier
void __DMB (void)M0, M3DMBData Memory Barrier
uint32_t __REV (uint32_t value)M0, M3REVReverse byte order in integer value.
uint32_t __REV16 (uint16_t value)M0, M3REV16Reverse byte order in unsigned short value.
sint32_t __REVSH (sint16_t value)M0, M3REVSHReverse byte order in signed short value with sign extension to integer.
uint32_t __RBIT (uint32_t value)M3RBITReverse bit order of value
uint8_t __LDREXB (uint8_t *addr)M3LDREXBLoad exclusive byte
uint16_t __LDREXH (uint16_t *addr)M3LDREXHLoad exclusive half-word
uint32_t __LDREXW (uint32_t *addr)M3LDREXWLoad exclusive word
uint32_t __STREXB (uint8_t value, uint8_t *addr)M3STREXBStore exclusive byte
uint32_t __STREXB (uint16_t value, uint16_t *addr)M3STREXHStore exclusive half-word
uint32_t __STREXB (uint32_t value, uint32_t *addr)M3STREXWStore exclusive word
void __CLREX (void)M3CLREXRemove the exclusive lock created by __LDREXB, __LDREXH, or __LDREXW
+ + +

NVIC Access Functions

+

+ The CMSIS provides access to the NVIC via the register interface structure and several helper + functions that simplify the setup of the NVIC. The CMSIS HAL uses IRQ numbers (IRQn) to + identify the interrupts. The first device interrupt has the IRQn value 0. Therefore negative + IRQn values are used for processor core exceptions. +

+

+ For the IRQn values of core exceptions the file device.h provides + the following enum names. +

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
Core Exception enum ValueCoreIRQnDescription
NonMaskableInt_IRQnM0, M3-14Cortex-M Non Maskable Interrupt
HardFault_IRQnM0, M3-13Cortex-M Hard Fault Interrupt
MemoryManagement_IRQnM3-12Cortex-M Memory Management Interrupt
BusFault_IRQnM3-11Cortex-M Bus Fault Interrupt
UsageFault_IRQnM3-10Cortex-M Usage Fault Interrupt
SVCall_IRQnM0, M3-5Cortex-M SV Call Interrupt
DebugMonitor_IRQnM3-4Cortex-M Debug Monitor Interrupt
PendSV_IRQnM0, M3-2Cortex-M Pend SV Interrupt
SysTick_IRQnM0, M3-1Cortex-M System Tick Interrupt
+ +

The following functions simplify the setup of the NVIC. +The functions are defined as static inline.

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
NameCoreParameterDescription
void NVIC_SetPriorityGrouping (uint32_t PriorityGroup)M3Priority Grouping ValueSet the Priority Grouping (Groups . Subgroups)
uint32_t NVIC_GetPriorityGrouping (void)M3(void)Get the Priority Grouping (Groups . Subgroups)
void NVIC_EnableIRQ (IRQn_Type IRQn)M0, M3IRQ NumberEnable IRQn
void NVIC_DisableIRQ (IRQn_Type IRQn)M0, M3IRQ NumberDisable IRQn
uint32_t NVIC_GetPendingIRQ (IRQn_Type IRQn)M0, M3IRQ NumberReturn 1 if IRQn is pending else 0
void NVIC_SetPendingIRQ (IRQn_Type IRQn)M0, M3IRQ NumberSet IRQn Pending
void NVIC_ClearPendingIRQ (IRQn_Type IRQn)M0, M3IRQ NumberClear IRQn Pending Status
uint32_t NVIC_GetActive (IRQn_Type IRQn)M3IRQ NumberReturn 1 if IRQn is active else 0
void NVIC_SetPriority (IRQn_Type IRQn, uint32_t priority)M0, M3IRQ Number, PrioritySet Priority for IRQn
+ (not threadsafe for Cortex-M0)
uint32_t NVIC_GetPriority (IRQn_Type IRQn)M0, M3IRQ NumberGet Priority for IRQn
uint32_t NVIC_EncodePriority (uint32_t PriorityGroup, uint32_t PreemptPriority, uint32_t SubPriority)M3IRQ Number, Priority Group, Preemptive Priority, Sub PriorityEncode priority for given group, preemptive and sub priority
NVIC_DecodePriority (uint32_t Priority, uint32_t PriorityGroup, uint32_t* pPreemptPriority, uint32_t* pSubPriority)M3IRQ Number, Priority, pointer to Priority Group, pointer to Preemptive Priority, pointer to Sub PriorityDeccode given priority to group, preemptive and sub priority
void NVIC_SystemReset (void)M0, M3(void)Resets the System
+

Note

+ + + +

SysTick Configuration Function

+ +

The following function is used to configure the SysTick timer and start the +SysTick interrupt.

+ + + + + + + + + + + + + + +
NameParameterDescription
uint32_t SysTickConfig + (uint32_t ticks)ticks is SysTick counter reload valueSetup the SysTick timer and enable the SysTick interrupt. After this + call the SysTick timer creates interrupts with the specified time + interval.
+
+ Return: 0 when successful, 1 on failure.
+
+ + +

Cortex-M3 ITM Debug Access

+ +

The Cortex-M3 incorporates the Instrumented Trace Macrocell (ITM) that +provides together with the Serial Viewer Output trace capabilities for the +microcontroller system. The ITM has 32 communication channels; two ITM +communication channels are used by CMSIS to output the following information:

+ +

Note

+ + +

The prototype of the ITM_SendChar routine is shown in the +table below.

+ + + + + + + + + + + + + + +
NameParameterDescription
void uint32_t ITM_SendChar(uint32_t chr)character to outputThe function outputs a character via the ITM channel 0. The + function returns when no debugger is connected that has booked the + output. It is blocking when a debugger is connected, but the + previous character send is not transmitted.

+ Return: the input character 'chr'.
+ +

+ Example for the usage of the ITM Channel 31 for RTOS Kernels: +

+
+  // check if debugger connected and ITM channel enabled for tracing
+  if ((CoreDebug->DEMCR & CoreDebug_DEMCR_TRCENA) &&
+  (ITM->TCR & ITM_TCR_ITMENA) &&
+  (ITM->TER & (1UL << 31))) {
+    // transmit trace data
+    while (ITM->PORT31_U32 == 0);
+    ITM->PORT[31].u8 = task_id;      // id of next task
+    while (ITM->PORT[31].u32 == 0);
+    ITM->PORT[31].u32 = task_status; // status information
+  }
+ + +

Cortex-M3 additional Debug Access

+ +

CMSIS provides additional debug functions to enlarge the Cortex-M3 Debug Access. +Data can be transmitted via a certain global buffer variable towards the target system.

+ +

The buffer variable and the prototypes of the additional functions are shown in the +table below.

+ + + + + + + + + + + + + + + + + + + + + + + + +
NameParameterDescription
extern volatile int ITM_RxBuffer Buffer to transmit data towards debug system.

+ Value 0x5AA55AA5 indicates that buffer is empty.
int ITM_ReceiveChar (void)noneThe nonblocking functions returns the character stored in + ITM_RxBuffer.

+ Return: -1 indicates that no character was received.
int ITM_CheckChar (void)noneThe function checks if a character is available in ITM_RxBuffer.

+ Return: 1 indicates that a character is available, 0 indicates that + no character is available.
+ + +

CMSIS Example

+

+ The following section shows a typical example for using the CMSIS layer in user applications. + The example is based on a STM32F10x Device. +

+
+#include "stm32f10x.h"
+
+volatile uint32_t msTicks;                       /* timeTicks counter */
+
+void SysTick_Handler(void) {
+  msTicks++;                                     /* increment timeTicks counter */
+}
+
+__INLINE static void Delay (uint32_t dlyTicks) {
+  uint32_t curTicks = msTicks;
+
+  while ((msTicks - curTicks) < dlyTicks);
+}
+
+__INLINE static void LED_Config(void) {
+  ;                                              /* Configure the LEDs */
+}
+
+__INLINE static void LED_On (uint32_t led) {
+  ;                                              /* Turn On  LED */
+}
+
+__INLINE static void LED_Off (uint32_t led) {
+  ;                                              /* Turn Off LED */
+}
+
+int main (void) {
+  if (SysTick_Config (SystemCoreClock / 1000)) { /* Setup SysTick for 1 msec interrupts */
+    ;                                            /* Handle Error */
+    while (1);
+  }
+  
+  LED_Config();                                  /* configure the LEDs */                            
+ 
+  while(1) {
+    LED_On (0x100);                              /* Turn  on the LED   */
+    Delay (100);                                 /* delay  100 Msec    */
+    LED_Off (0x100);                             /* Turn off the LED   */
+    Delay (100);                                 /* delay  100 Msec    */
+  }
+}
+ + + \ No newline at end of file -- cgit v1.2.3