modm API documentation

#include <modm/platform/i2c/i2c_master_4.hpp>

Inheritance diagram for modm::platform::I2cMaster4:
modm::I2cMaster modm::PeripheralDriver modm::I2c

Public Typedefs

using ConfigurationHandler = void (*)()
 The signature of the configuration function.
 

Public Types

enum  DetachCause : uint8_t { DetachCause::NormalStop, DetachCause::ErrorCondition, DetachCause::FailedToAttach }
 
enum  Error : uint8_t {
  Error::NoError, Error::SoftwareReset, Error::AddressNack, Error::DataNack,
  Error::ArbitrationLost, Error::BusCondition, Error::BusBusy, Error::Unknown
}
 Errors that can happen during master operation. More...
 
enum  PullUps { PullUps::External, PullUps::Internal }
 
enum  ResetDevices : uint32_t { ResetDevices::NoReset = 0, ResetDevices::LowSpeed = 10'000, ResetDevices::Standard = 100'000, ResetDevices::Fast = 400'000 }
 
enum  TransactionState : uint8_t { TransactionState::Idle, TransactionState::Busy, TransactionState::Error }
 State of a I2c Transaction. More...
 
enum  Operation : uint8_t { Operation::Stop = 0, Operation::Restart = 1, Operation::Write = 2, Operation::Read = 3 }
 All possible I2C Operations. More...
 
enum  OperationAfterRead : uint8_t { OperationAfterRead::Stop = uint8_t(Operation::Stop), OperationAfterRead::Restart = uint8_t(Operation::Restart) }
 Further operations after read operation. More...
 
enum  OperationAfterStart : uint8_t { OperationAfterStart::Stop = uint8_t(Operation::Stop), OperationAfterStart::Write = uint8_t(Operation::Write), OperationAfterStart::Read = uint8_t(Operation::Read) }
 Further operations after start operation. More...
 
enum  OperationAfterWrite : uint8_t { OperationAfterWrite::Stop = uint8_t(Operation::Stop), OperationAfterWrite::Restart = uint8_t(Operation::Restart), OperationAfterWrite::Write = uint8_t(Operation::Write) }
 Further operations after write operation. More...
 

Static Public Member Functions

template<class... Signals>
static void connect (PullUps pullups=PullUps::External, ResetDevices reset=ResetDevices::Standard)
 
template<class SystemClock , baudrate_t baudrate = kBd(100), percent_t tolerance = pct(5)>
static void initialize (uint8_t isrPriority=10u)
 
static bool start (I2cTransaction *transaction, ConfigurationHandler handler=nullptr)
 
static Error getErrorState ()
 
static void reset ()
 
static void acknowledgeInterruptFlag ()
 
template<uint64_t available, uint64_t requested, percent_t tolerance>
static void assertBaudrateInTolerance ()
 
template<double available, double requested, percent_t tolerance>
static void assertDurationInTolerance ()
 
static void configurePurpose ()
 configures a peripheral for a specific purpose
 
static bool getInterruptFlag ()
 Read an interrupt flag.
 
static void getParameter ()
 returns a parameter
 
template<class SystemClock , baudrate_t baudrate = 100_kBd, percent_t tolerance = 5_pct>
static void initialize ()
 
static void initialize ()
 initializes the peripheral, must be called before use.
 
template<class Scl >
static void resetDevices (uint32_t baudrate=100'000)
 
static void setParameter ()
 sets a parameter
 

Static Public Attributes

static constexpr size_t TransactionBufferSize = 8
 
static constexpr uint8_t Read = 0x01
 Add the Read bit to the slave address.
 
static constexpr uint8_t Write = 0x00
 Add the Write bit to the slave address.
 

Detailed Description

I2cMaster implementation of I2C4 module.

Interrupts must be enabled.

Author
Georgi Grinshpun
Niklas Hauser
Sascha Schade (strongly-typed)

Member Enumeration Documentation

enum modm::I2c::DetachCause : uint8_t
inheritedstrong

This tells the I2cTransaction why it was detached

See also
I2cTransaction
Enum ValuesDocumentation
NormalStop 

All operations finished normally.

ErrorCondition 

A bus error occurred and the bus was reset.

FailedToAttach 

The I2cTransaction failed to attach to the I2cMaster.

enum modm::I2cMaster::Error : uint8_t
inheritedstrong

Errors that can happen during master operation.

Enum ValuesDocumentation
NoError 

No Error occurred.

SoftwareReset 

The master was reset in software.

AddressNack 

Address was transmitted and NACK received.

DataNack 

Data was transmitted and NACK received.

ArbitrationLost 

Arbitration was lost during writing or reading.

BusCondition 

Misplaced Start or Stop condition.

BusBusy 

Bus is busy during Start condition.

Unknown 

Unknown error condition.

enum modm::I2c::Operation : uint8_t
inheritedstrong

All possible I2C Operations.

I2C Operations that the I2cTransaction can give the master on callback

See also
I2cTransaction
Enum ValuesDocumentation
Stop 

Generate a Stop Condition.

Restart 

Generate a Restart.

Write 

Write data to the slave.

Read 

Read data from the slave.

enum modm::I2c::OperationAfterRead : uint8_t
inheritedstrong

Further operations after read operation.

Enum ValuesDocumentation
Stop 

Generate a Stop Condition.

Restart 

Generate a Restart.

enum modm::I2c::OperationAfterStart : uint8_t
inheritedstrong

Further operations after start operation.

Enum ValuesDocumentation
Stop 

Generate a Stop Condition.

Write 

Write data to the slave.

Read 

Read data from the slave.

enum modm::I2c::OperationAfterWrite : uint8_t
inheritedstrong

Further operations after write operation.

Enum ValuesDocumentation
Stop 

Generate a Stop Condition.

Restart 

Generate a Restart.

Write 

Write data to the slave.

enum modm::I2cMaster::PullUps
inheritedstrong
Enum ValuesDocumentation
External 

External pull-ups exists in SDA and SCL.

Internal 

Use weak internal pull-ups on SDA and SCL.

enum modm::I2cMaster::ResetDevices : uint32_t
inheritedstrong
Enum ValuesDocumentation
NoReset 

Do not reset devices.

LowSpeed 

Low-Speed datarate of 10kHz.

Standard 

Standard datarate of 100kHz.

Fast 

Fast datarate of 400kHz.

enum modm::I2c::TransactionState : uint8_t
inheritedstrong

State of a I2c Transaction.

Enum ValuesDocumentation
Idle 

No error occurred, detached normally.

Busy 

The transaction object is busy with data transfer.

Error 

An error occurred, check the masters getErrorCode()

Member Function Documentation

static void modm::PeripheralDriver::acknowledgeInterruptFlag ( )
inheritedstatic

Acknowledge an interrupt flag.

We use acknowledge here, since it describes the intention rather than the actual implementation.

template<uint64_t available, uint64_t requested, percent_t tolerance>
static void modm::PeripheralDriver::assertBaudrateInTolerance ( )
inheritedinlinestatic

Since baudrates are usually generated by prescaling a system clock, only several distinct values can be generated. This method checks if the user requested baudrate is within error tolerance of the system achievable baudrate.

template<class SystemClock , baudrate_t baudrate = 100_kBd, percent_t tolerance = 5_pct>
static void modm::I2cMaster::initialize ( )
inheritedstatic

Initializes the hardware and sets the datarate.

Template Parameters
SystemClockthe currently active system clock
baudratethe desired baudrate in Hz
tolerancethe allowed absolute tolerance for the resulting baudrate
template<class SystemClock , baudrate_t baudrate = kBd(100), percent_t tolerance = pct(5)>
static void modm::platform::I2cMaster4::initialize ( uint8_t  isrPriority = 10u)
inlinestatic

Set up the I2C module for master operation.

Parameters
rateStandard or Fast, High datarate is not supported
template<class Scl >
static void modm::I2c::resetDevices ( uint32_t  baudrate = 100'000)
inheritedinlinestatic

Reset all slave devices connected to an I2C bus.

During normal operation, I2C slave device may pull the SDA line low. However, if the master is reset during a transaction, the I2C clock may stop while the slave is outputting a low data bit and the slave will continue to hold this bit (forever, and ever and ever). The I2C master is then unable to generate a I2C start condition, since SDA is still held low by the slave device, resulting in a deadlock.

"You can always get it back to standby mode by allowing the SDA line to float high and give it 9 clocks. This assures that the device will not receive the acknowledge bit at the end the current byte and will abort the command and go to standby."

See also
Application Note AN572 by Microchip
Warning
Must be called before connecting SDA and SCL to I2cMaster!
Template Parameters
SclThe clock pin of the bus to be reset.

The documentation for this class was generated from the following files: