Instrumentation Trace Macrocell

Configure ITM for passthrough of DWT messages and user-defined output through stimulus ports. More...

Classes
struct	ITMOptions
	ITM configuration options. More...

Macros
#define	ITM_ENABLE_STIMULUS_PORTS_ALL   0xFFFFFFFF
	Enable all ITM stimuls ports. More...

Enumerations
enum	ITMGlobalTimestampFrequency { ITMGlobalTimestampFrequencyDisabled = 0 , ITMGlobalTimestampFrequencyPosition7 = 1 , ITMGlobalTimestampFrequencyPosition13 = 2 , ITMGlobalTimestampFrequencyIfOutputFIFOEmpty = 3 }
	Global timestamp frequency. More...
enum	ITMLocalTimestampPrescaler { ITMLocalTimestampPrescalerNoPrescaling = 0 , ITMLocalTimestampPrescalerDivideBy4 = 1 , ITMLocalTimestampPrescalerDivideBy10 = 2 , ITMLocalTimestampPrescalerDivideBy64 = 3 }
	Local timestamp frequency. More...

Functions
static void	ITMSetup (const ITMOptions *options)
	Configures ITM as requested. More...
static bool	ITMIsPortEnabled (uint8_t port)
	Checks if stimulus port is enabled. More...
static void	ITMWrite8 (uint8_t port, uint8_t c)
	Writes 8-bit value to stimulus port. More...
static void	ITMWrite16 (uint8_t port, uint16_t value)
	Writes 16-bit value to stimulus port. More...
static void	ITMWrite32 (uint8_t port, uint32_t value)
	Writes 32-bit value to stimulus port. More...
static void	ITMWriteBuffer (uint8_t port, const void *buffer, size_t size)
	Writes buffer to stimulus port. More...

Detailed Description

Configure ITM for passthrough of DWT messages and user-defined output through stimulus ports.

Instrumentation Trace Macrocell provides following capabilites:

• Output of user-defined data in packets of 1,2 or 4 bytes through up to 255 separate stimulus ports
• Passthrough of DWT data (See Data Watchpoint & Trace Unit)
• Periodic timestamp generation (Needs additional configuration in Data Watchpoint & Trace Unit)

Reference: ARMv7-M Architecture Reference Manual, chapter C1.7 The Instrumentation Trace Macrocell

Macro Definition Documentation

ITM_ENABLE_STIMULUS_PORTS_ALL

#define ITM_ENABLE_STIMULUS_PORTS_ALL   0xFFFFFFFF

Enable all ITM stimuls ports.

Set as value of ITMOptions::EnabledStimulusPorts to enable all available stimulus ports.

Enumeration Type Documentation

ITMGlobalTimestampFrequency

enum ITMGlobalTimestampFrequency

Global timestamp frequency.

See ITMOptions::GlobalTimestampFrequency for more details

ITMLocalTimestampPrescaler

enum ITMLocalTimestampPrescaler

Local timestamp frequency.

See ITMOptions::LocalTimestampPrescaler for more details

Function Documentation

ITMSetup()

void ITMSetup ( const ITMOptions *  options )

inlinestatic

Configures ITM as requested.

Note that there is no validation if specified configuration is valid (e.g. timestamp prescaler values) and there are no checks to verify MCU capabilities (enabling timestamp when it is not implemented).

Parameters

options

ITM configuration

ITMIsPortEnabled()

bool ITMIsPortEnabled ( uint8_t  port )

inlinestatic

Checks if stimulus port is enabled.

Parameters

port	Port to check

Returns

true Port is enabled

false Port is disabled (or not available)

ITMWrite8()

void ITMWrite8 ( uint8_t  port, uint8_t  c  )

inlinestatic

Writes 8-bit value to stimulus port.

Parameters

port	Port
c	Value to be written

ITMWrite16()

void ITMWrite16 ( uint8_t  port, uint16_t  value  )

inlinestatic

Writes 16-bit value to stimulus port.

Parameters

port	Port
value	Value to be written

ITMWrite32()

void ITMWrite32 ( uint8_t  port, uint32_t  value  )

inlinestatic

Writes 32-bit value to stimulus port.

Parameters

port	Port
value	Value to be written

ITMWriteBuffer()

void ITMWriteBuffer ( uint8_t  port, const void *  buffer, size_t  size  )

inlinestatic

Writes buffer to stimulus port.

Writes buffer to stimulus port using largest packet size possible - starts with 32-bit writes, followed by 16-bit writes and 8-bit write.

Data from buffer are memcpy'ied which is subject to compiler optimization and might result in unaligned memory access if compiler decides it is valid (e.g. on ARMv7-M platform).

Parameters

port	Port
buffer	Buffer to be written (must not be NULL)
size	Size of buffer to be written