SMART ARM-based Microcontrollers
AT06863: SAM4L Peripheral Event Controller
(PEVC) Driver
APPLICATION NOTE
Introduction
®
®
This driver for Atmel | SMART ARM -based microcontrollers provides a
unified interface for the configuration and management of the Event
Channels.
The peripheral event generators and users are interconnected by a network
known as the Peripheral Event System.
The Peripheral Event System allows low latency peripheral-to-peripheral
signaling without CPU intervention, and without consuming system
resources such as bus or RAM bandwidth. This offloads the CPU and
system resources compared to a traditional interrupt-based software driven
system.
Devices from the following series can use this module:
•
Atmel | SMART SAM4L
The outline of this documentation is as follows:
•
Prerequisites
•
Module Overview
•
Special Considerations
•
Extra Information
•
Examples
•
API Overview
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Table of Contents
Introduction......................................................................................................................1
1. Software License....................................................................................................... 4
2. Prerequisites..............................................................................................................5
3. Module Overview....................................................................................................... 6
3.1.
3.2.
3.3.
3.4.
3.5.
Event Channels............................................................................................................................ 6
Event Users..................................................................................................................................7
Event Shaper (EVS)..................................................................................................................... 7
3.3.1.
Input Glitch Filter (IGF).................................................................................................. 7
Physical Connection.....................................................................................................................7
Configuring Events....................................................................................................................... 7
3.5.1.
Source Peripheral.......................................................................................................... 7
3.5.2.
Event System.................................................................................................................7
3.5.3.
Destination Peripheral................................................................................................... 8
4. Special Considerations.............................................................................................. 9
5. Extra Information..................................................................................................... 10
6. Examples................................................................................................................. 11
7. API Overview........................................................................................................... 12
7.1.
7.2.
7.3.
Structure Definitions................................................................................................................... 12
7.1.1.
Struct events_ch_conf................................................................................................. 12
7.1.2.
Struct events_conf....................................................................................................... 12
Macro Definitions........................................................................................................................12
7.2.1.
Macro EVENT_CHANNEL_N...................................................................................... 12
7.2.2.
Macro EVENT_GENERATOR_N.................................................................................12
Function Definitions....................................................................................................................12
7.3.1.
7.3.2.
7.3.3.
7.3.4.
7.3.5.
Function events_ch_clear_overrun_status()................................................................12
Function events_ch_clear_trigger_status()..................................................................13
Function events_ch_configure().................................................................................. 13
Function events_ch_disable()......................................................................................13
Function events_ch_disable_software_trigger().......................................................... 13
7.3.6.
7.3.7.
7.3.8.
7.3.9.
7.3.10.
7.3.11.
7.3.12.
7.3.13.
7.3.14.
7.3.15.
Function events_ch_enable()...................................................................................... 14
Function events_ch_enable_software_trigger()...........................................................14
Function events_ch_get_config_defaults().................................................................. 14
Function events_ch_is_enabled()................................................................................14
Function events_ch_is_overrun()................................................................................ 15
Function events_ch_is_ready()....................................................................................15
Function events_ch_is_triggered().............................................................................. 16
Function events_ch_software_trigger()....................................................................... 16
Function events_disable()............................................................................................16
Function events_enable()............................................................................................ 16
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7.3.16.
7.4.
Function events_get_config_defaults()........................................................................17
7.3.17. Function events_init().................................................................................................. 17
7.3.18. Function events_set_igf_divider()................................................................................17
Enumeration Definitions............................................................................................................. 17
7.4.1.
Enum events_igf_divider............................................................................................. 17
7.4.2.
Enum events_igf_edge................................................................................................ 18
8. Extra Information for Peripheral Event Controller Driver......................................... 19
8.1.
8.2.
8.3.
8.4.
Acronyms....................................................................................................................................19
Dependencies.............................................................................................................................19
Errata..........................................................................................................................................19
Module History............................................................................................................................19
9. Examples for Peripheral Event Controller Driver..................................................... 20
9.1.
9.2.
9.3.
Quick Start Guide for the Peripheral Event Controller Driver..................................................... 20
9.1.1.
Use Cases................................................................................................................... 20
9.1.2.
Basic Use Case........................................................................................................... 20
9.1.3.
Setup Steps................................................................................................................. 20
9.1.4.
Basic Usage.................................................................................................................21
Example for the Peripheral Event System - AST/PDCA.............................................................21
9.2.1.
Introduction.................................................................................................................. 21
9.2.2.
Main Files.................................................................................................................... 21
9.2.3.
Compilation Information...............................................................................................22
9.2.4.
Device Information.......................................................................................................22
9.2.5.
Configuration Information............................................................................................ 22
Example for the Peripheral Event System - GPIO/PDCA...........................................................22
9.3.1.
Introduction.................................................................................................................. 22
9.3.2.
Main Files.................................................................................................................... 22
9.3.3.
Compilation Information...............................................................................................22
9.3.4.
Device Information.......................................................................................................22
9.3.5.
Configuration Information............................................................................................ 22
10. Document Revision History..................................................................................... 24
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1.
Software License
Redistribution and use in source and binary forms, with or without modification, are permitted provided
that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice, this list of conditions and the
following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
following disclaimer in the documentation and/or other materials provided with the distribution.
3. The name of Atmel may not be used to endorse or promote products derived from this software without
specific prior written permission.
4. This software may only be redistributed and used in connection with an Atmel microcontroller product.
THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE EXPRESSLY AND SPECIFICALLY
DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.
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2.
Prerequisites
There are no prerequisites for this module.
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3.
Module Overview
Peripherals within the SAM4L device are capable of generating two types of actions in response to a
given stimulus; they can set a register flag for later intervention by the CPU (using interrupt or polling
methods), or they can generate event signals which can be internally routed directly to other peripherals
within the device. The use of events allows for direct actions to be performed in one peripheral in
response to a stimulus in another without CPU intervention. This can lower the overall power
consumption of the system if the CPU is able to remain in sleep modes for longer periods, and lowers the
latency of the system response.
The Peripheral Event System is comprised of a number of freely configurable Event Channels, plus a
number of fixed Event Users. Each Event Channel can be configured to select the input peripheral that
will generate the events on the channel, as well as the Event Shaper (EVS) and Input Glitch Filter (IGF)
operating modes. The fixed-function Event Users, connected to peripherals within the device, can then
subscribe to an Event Channel in a one-to-many relationship in order to receive events as they are
generated. An overview of the event system chain is shown in Figure 3-1 Module Overview on page
6.
Figure 3-1 Module Overview
User
Generator
Peripheral
Event System
User/
Generator
Generator
There are many different events that can be routed in the device, which can then trigger many different
actions. For example, an Analog Comparator module could be configured to generate an event when the
input signal rises above the compare threshold, which then triggers a Timer Counter module to capture
the current count value for later use.
3.1.
Event Channels
The Peripheral Event Controller module in the SAM4L device consists of several channels, which can be
freely linked to an Event Generator (i.e. a peripheral within the device that is capable of generating
events). Each channel can be individually configured to select the generator peripheral, signal path, Event
Shaper (EVS), and Input Glitch Filter (IGF) applied to the input event signal, before being passed to any
event user(s).
Event Channels can support multiple users within the device in a standardized manner; when an Event
User is linked to an Event Channel, the channel will automatically handshake with all attached users to
ensure that all modules correctly receive and acknowledge the event.
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3.2.
Event Users
Event Users are able to subscribe to an Event Channel, once it has been configured. Each Event User
consists of a fixed connection to one of the peripherals within the device (for example, an ADC module or
Timer module) and is capable of being connected to a single Event Channel.
3.3.
Event Shaper (EVS)
The Peripheral Event Controller module contains Event Shapers (EVS) for external inputs and general
purpose waveforms (i.e. timer outputs or Generic Clocks) that require synchronisation and/or edge
detection prior to peripheral event propagation.
Each Event Shaper is responsible for shaping one generator input prior to it going through an Event
Channel.
Refer to the module configuration section at the end of the Peripheral Event Controller (PEVC) section in
the device datasheet for the specific configuration of Event Shapers and Input Glitch Filters.
3.3.1.
Input Glitch Filter (IGF)
The Peripheral Event Controller module contains Input Glitch Filters (IGF) specifically to allow I/O inputs
to be sampled periodically. Input Glitch Filtering can be turned on or off in the Event Shaper associated
with the Event Channel.
3.4.
Physical Connection
Figure 3-2 Physical Connection on page 7 shows how this module is interconnected within the device.
Figure 3-2 Physical Connection
Source
Peripherals
3.5.
Source
MUXes
PEVC
Event Channels
Channel
MUXes
PEVC
Event Users
Destination
Peripherals
Configuring Events
Several steps are required to properly configure an event chain, so that hardware peripherals can
respond to events generated by each other, listed below.
3.5.1.
Source Peripheral
1.
2.
3.5.2.
The source peripheral (that will generate events) must be configured and enabled.
The source peripheral (that will generate events) must have an output event enabled.
Event System
1.
2.
The event system channel must be configured and enabled, with the correct source peripheral
selected as the channel's Event Generator.
The event system user must be configured and enabled, with the correct source Event Channel
selected as the source.
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3.5.3.
Destination Peripheral
1.
2.
The destination peripheral (that will receive events) must be configured and enabled.
The destination peripheral (that will receive events) must have an input event enabled.
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4.
Special Considerations
There are no special considerations for this module.
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5.
Extra Information
For extra information, see Extra Information for Peripheral Event Controller Driver. This includes:
•
Acronyms
•
Dependencies
•
Errata
•
Module History
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6.
Examples
For a list of examples related to this driver, see Examples for Peripheral Event Controller Driver.
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7.
API Overview
7.1.
Structure Definitions
7.1.1.
Struct events_ch_conf
Configuration structure for an Event Channel.
Table 7-1 Members
7.1.2.
Type
Name
Description
uint32_t
channel_id
Channel to configure (user)
uint32_t
generator_id
Event generator to connect to the channel
enum events_igf_edge
igf_edge
Edge detection for Event Channels
bool
shaper_enable
Enable Event Shaper (EVS) or not
Struct events_conf
Configuration structure for event module.
Table 7-2 Members
Type
Name
Description
enum events_igf_divider
igf_divider
Input Glitch Filter divider
7.2.
Macro Definitions
7.2.1.
Macro EVENT_CHANNEL_N
#define EVENT_CHANNEL_N
Maximum number for Event Channels (users).
7.2.2.
Macro EVENT_GENERATOR_N
#define EVENT_GENERATOR_N
Maximum number for event generator.
7.3.
Function Definitions
7.3.1.
Function events_ch_clear_overrun_status()
Clear the overrun status of an Event Channel.
void events_ch_clear_overrun_status(
uint32_t channel_id)
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Table 7-3 Parameters
7.3.2.
Data direction
Parameter name
Description
[in]
channel_id
Event Channel ID
Function events_ch_clear_trigger_status()
Clear the trigger status of an Event Channel.
void events_ch_clear_trigger_status(
uint32_t channel_id)
Table 7-4 Parameters
7.3.3.
Data direction
Parameter name
Description
[in]
channel_id
Event Channel ID
Function events_ch_configure()
Configure an Event Channel.
void events_ch_configure(
struct events_ch_conf *const config)
Table 7-5 Parameters
7.3.4.
Data direction
Parameter name
Description
[in, out]
config
Configuration settings for the Event Channel
Function events_ch_disable()
Disable an Event Channel.
void events_ch_disable(
uint32_t channel_id)
Table 7-6 Parameters
7.3.5.
Data direction
Parameter name
Description
[in]
channel_id
Event Channel ID
Function events_ch_disable_software_trigger()
Disable the software trigger for an Event Channel.
void events_ch_disable_software_trigger(
uint32_t channel_id)
Table 7-7 Parameters
Data direction
Parameter name
Description
[in]
channel_id
Event Channel ID
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7.3.6.
Function events_ch_enable()
Enable an Event Channel.
void events_ch_enable(
uint32_t channel_id)
Table 7-8 Parameters
7.3.7.
Data direction
Parameter name
Description
[in]
channel_id
Event Channel ID
Function events_ch_enable_software_trigger()
Enable the software trigger for an Event Channel.
void events_ch_enable_software_trigger(
uint32_t channel_id)
Table 7-9 Parameters
7.3.8.
Data direction
Parameter name
Description
[in]
channel_id
Event Channel ID
Function events_ch_get_config_defaults()
Initialize an Event Channel configuration structure to defaults.
void events_ch_get_config_defaults(
struct events_ch_conf *const config)
The default configuration is as follows:
•
Channel ID is initialized to invalid number
•
Generator ID is initialized to invalid number
•
Event shaper is disabled
•
Event Input Glitch Filter is disabled
Table 7-10 Parameters
7.3.9.
Data direction
Parameter name
Description
[out]
config
Configuration structure to initialize to default values
Function events_ch_is_enabled()
Get the status (enabled or disabled) of an Event Channel.
bool events_ch_is_enabled(
uint32_t channel_id)
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Table 7-11 Parameters
Data direction
Parameter name
Description
[in]
channel_id
Event Channel ID
Returns
The Event Channel enabled/disabled status.
Table 7-12 Return Values
7.3.10.
Return value
Description
true
Event Channel is enabled
false
Event Channel is disabled
Function events_ch_is_overrun()
Get the overrun status of an Event Channel.
bool events_ch_is_overrun(
uint32_t channel_id)
Table 7-13 Parameters
Data direction
Parameter name
Description
[in]
channel_id
Event Channel ID
Returns
The Event Channel overrun status.
Table 7-14 Return Values
7.3.11.
Return value
Description
true
A channel overrun event has occurred
false
A channel overrun event has not occurred
Function events_ch_is_ready()
Get the busy status of an Event Channel.
bool events_ch_is_ready(
uint32_t channel_id)
Table 7-15 Parameters
Data direction
Parameter name
Description
[in]
channel_id
Event Channel ID
Returns
The Event Channel busy status.
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Table 7-16 Return Values
7.3.12.
Return value
Description
true
If the Event Channel is ready to be used
false
If the Event Channel is currently busy
Function events_ch_is_triggered()
Get the trigger status of an Event Channel.
bool events_ch_is_triggered(
uint32_t channel_id)
Table 7-17 Parameters
Data direction
Parameter name
Description
[in]
channel_id
Event Channel ID
Returns
The Event Channel trigger status.
Table 7-18 Return Values
7.3.13.
Return value
Description
true
A channel event has occurred
false
A channel event has not occurred
Function events_ch_software_trigger()
Trigger a Software Event for the corresponding Event Channel.
void events_ch_software_trigger(
uint32_t channel_id)
Table 7-19 Parameters
7.3.14.
Data direction
Parameter name
Description
[in]
channel_id
Event Channel ID
Function events_disable()
Disable the events module.
void events_disable( void )
7.3.15.
Function events_enable()
Enable the events module.
void events_enable( void )
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7.3.16.
Function events_get_config_defaults()
Initialize an events configuration structure to defaults.
void events_get_config_defaults(
struct events_conf *const config)
The default configuration is as follows:
•
Input Glitch Filter Divider is set to EVENT_IGF_DIVIDER_1024
Table 7-20 Parameters
7.3.17.
Data direction
Parameter name
Description
[out]
config
Configuration structure to initialize to default values
Function events_init()
Initialize the events module.
void events_init(
struct events_conf *const config)
Table 7-21 Parameters
7.3.18.
Data direction
Parameter name
Description
[in]
config
Configuration structure to initialize to default values
Function events_set_igf_divider()
Set the Input Glitch Filter Divider.
void events_set_igf_divider(
enum events_igf_divider divider)
Table 7-22 Parameters
Data direction
Parameter name
Description
[in]
divider
Input Glitch Filter divider
Note: As stated in the datasheet, there is one divider value for all Event Shaper (EVS) instances.
7.4.
Enumeration Definitions
7.4.1.
Enum events_igf_divider
Enumerate for the possible division ratios of an Input Glitch Filter.
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Table 7-23 Members
7.4.2.
Enum value
Description
EVENT_IGF_DIVIDER_1
Select a prescaler division ratio of 1
EVENT_IGF_DIVIDER_2
Select a prescaler division ratio of 2
EVENT_IGF_DIVIDER_4
Select a prescaler division ratio of 4
EVENT_IGF_DIVIDER_8
Select a prescaler division ratio of 8
EVENT_IGF_DIVIDER_16
Select a prescaler division ratio of 16
EVENT_IGF_DIVIDER_32
Select a prescaler division ratio of 32
EVENT_IGF_DIVIDER_64
Select a prescaler division ratio of 64
EVENT_IGF_DIVIDER_128
Select a prescaler division ratio of 128
EVENT_IGF_DIVIDER_256
Select a prescaler division ratio of 256
EVENT_IGF_DIVIDER_512
Select a prescaler division ratio of 512
EVENT_IGF_DIVIDER_1024
Select a prescaler division ratio of 1024
EVENT_IGF_DIVIDER_2048
Select a prescaler division ratio of 2048
EVENT_IGF_DIVIDER_4096
Select a prescaler division ratio of 4096
EVENT_IGF_DIVIDER_8192
Select a prescaler division ratio of 8192
EVENT_IGF_DIVIDER_16384
Select a prescaler division ratio of 16384
EVENT_IGF_DIVIDER_32768
Select a prescaler division ratio of 32768
Enum events_igf_edge
Table 7-24 Members
Enum value
Description
EVENT_IGF_EDGE_NONE
Input Glitch Filter is disabled
EVENT_IGF_EDGE_RISING
Event detection through Input Glitch Filter on rising edge
EVENT_IGF_EDGE_FALLING
Event detection through Input Glitch Filter on falling edge
EVENT_IGF_EDGE_BOTH
Event detection through Input Glitch Filter on both edges
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8.
Extra Information for Peripheral Event Controller Driver
8.1.
Acronyms
Below is a table listing the acronyms used in this module, along with their intended meanings.
8.2.
Acronym
Definition
ADC
Analog to Digital Converter
AST
Asynchronous Timer
EVS
Event Shaper
IGF
Input Glitch Filter
PDCA
Peripheral DMA Controller
Dependencies
This driver has the following dependencies:
•
8.3.
None
Errata
There are no errata related to this driver.
8.4.
Module History
An overview of the module history is presented in the table below, with details on the enhancements and
fixes made to the module since its first release. The current version of this corresponds to the newest
version in the table.
Changelog
Initial document release
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9.
Examples for Peripheral Event Controller Driver
This is a list of the available Quick Start Guides (QSGs) and example applications for SAM4L Peripheral
Event Controller (PEVC) Driver. QSGs are simple examples with step-by-step instructions to configure
and use this driver in a selection of use cases. Note that a QSG can be compiled as a standalone
application or be added to the user application.
•
•
•
9.1.
Quick Start Guide for the Peripheral Event Controller Driver
Example for the Peripheral Event System - AST/PDCA
Example for the Peripheral Event System - GPIO/PDCA
Quick Start Guide for the Peripheral Event Controller Driver
This is the quick start guide for the SAM4L Peripheral Event Controller (PEVC) Driver, with step-by-step
instructions on how to configure and use the driver for a specific use case.
The use cases contain several code fragments. The code fragments in the steps for setup can be copied
into a custom initialization function, while the steps for usage can be copied into, e.g., the main
application function.
9.1.1.
Use Cases
•
9.1.2.
Basic Use Case
Basic Use Case
This use case will demonstrate how to use the Peripheral Event Controller on SAM4L_EK. In this use
case, one Event Channel is configured as:
•
Configure AST periodic event 0 as a generator
•
Configure PDCA channel 0 as a user to transfer one word
•
Enable the event shaper for the generator
9.1.3.
Setup Steps
9.1.3.1.
Prerequisites
This module requires the following service:
•
Clock Management (Sysclock)
9.1.3.2.
Code Example
Copy-paste the following setup code to your application:
static void init_events(void)
{
struct events_conf
events_config;
struct events_ch_conf ch_config;
/* Initialize event module */
events_get_config_defaults(&events_config);
events_init(&events_config);
events_enable();
/*
* Configure an event channel
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* - AST periodic event 0 --- Generator
* - PDCA channel 0
--- User
*/
events_ch_get_config_defaults(&ch_config);
ch_config.channel_id = PEVC_ID_USER_PDCA_0;
ch_config.generator_id = PEVC_ID_GEN_AST_2;
ch_config.shaper_enable = true;
ch_config.igf_edge = EVENT_IGF_EDGE_NONE;
events_ch_configure(&ch_config);
}
/* Enable the channel */
events_ch_enable(PEVC_ID_USER_PDCA_0);
Add this to the main loop or a setup function:
/* Initialize AST as event generator. */
init_ast();
/* Initialise events for this example. */
init_events();
/* Initialize the PDCA as event user */
init_pdca();
9.1.3.3.
Workflow
1.
Initialize AST to generate periodic event 0. see sam/drivers/events/example1 for more detail:
init_ast();
2.
Initialize the event module and enable it:
init_events();
3.
Initialize PDCA channel 0 to transfer data to USART. see sam/drivers/events/example1 for more
detail:
init_pdca();
9.1.4.
Basic Usage
After the channel is configured correctly and enabled, each time a new event from AST occurs, a
character is sent to the USART via PDCA without the use of the CPU.
9.2.
Example for the Peripheral Event System - AST/PDCA
9.2.1.
Introduction
This example shows how to use the Peripheral Event Controller. In the example, the AST generates a
periodic event which is transmitted to the PDCA. Each time a new event occurs, a character is sent to the
USART without the use of the CPU. The main loop of the function is a delay 500ms and toggle a LED
continuously to show CPU activity.
9.2.2.
Main Files
•
•
events.c: Events driver
events.h: Events driver header file
Atmel AT06863: SAM4L Peripheral Event Controller (PEVC) Driver [APPLICATION NOTE]
Atmel-42312B-SAM4L-Peripheral-Event-Controller-PEVC-Driver_AT06863_Application Note-07/2015
21
•
9.2.3.
events_example1.c: Events example 1 application
Compilation Information
®
®
This software is written for GNU GCC and IAR Embedded Workbench for Atmel . Other compilers may
or may not work.
9.2.4.
Device Information
SAM4L device can be used.
9.2.5.
Configuration Information
This example has been tested with the following configuration:
•
PC terminal settings:
•
115200 baud
•
8 data bits
•
no parity bit
•
1 stop bit
•
no flow control
9.3.
Example for the Peripheral Event System - GPIO/PDCA
9.3.1.
Introduction
This example shows how to use the Peripheral Event Controller. In the example, an I/O pin is configured
to trigger a GPIO event when detecting a falling edge. Each time a new event occurs, it will trigger the
PDCA to send a character to the USART without CPU usage.
9.3.2.
Main Files
•
•
•
9.3.3.
events.c: Events driver
events.h: Events driver header file
events_example2.c: Events example 2 application
Compilation Information
This software is written for GNU GCC and IAR Embedded Workbench for Atmel. Other compilers may or
may not work.
9.3.4.
Device Information
SAM4L device can be used.
9.3.5.
Configuration Information
This example has been tested with the following configuration:
•
PC terminal settings:
•
115200 baud
•
8 data bits
•
no parity bit
•
1 stop bit
Atmel AT06863: SAM4L Peripheral Event Controller (PEVC) Driver [APPLICATION NOTE]
Atmel-42312B-SAM4L-Peripheral-Event-Controller-PEVC-Driver_AT06863_Application Note-07/2015
22
•
no flow control
Atmel AT06863: SAM4L Peripheral Event Controller (PEVC) Driver [APPLICATION NOTE]
Atmel-42312B-SAM4L-Peripheral-Event-Controller-PEVC-Driver_AT06863_Application Note-07/2015
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10.
Document Revision History
Doc. Rev.
Date
Comments
42312B
07/2015
Updated title of application note and added list of supported devices
42312A
05/2014
Initial document release
Atmel AT06863: SAM4L Peripheral Event Controller (PEVC) Driver [APPLICATION NOTE]
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