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Wire: Define WIRE_HAS_TIMEOUT #362

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11 changes: 5 additions & 6 deletions libraries/Wire/src/Wire.cpp
View file Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -97,24 +97,23 @@ void TwoWire::setClock(uint32_t clock)
* master that has claimed the bus).
*
* When a timeout is triggered, a flag is set that can be queried with `getWireTimeoutFlag()` and is cleared
* when `clearWireTimeoutFlag()` or `setWireTimeoutUs()` is called.
* when `clearWireTimeoutFlag()` or `setWireTimeout()` is called.
*
* Note that this timeout can also trigger while waiting for clock stretching or waiting for a second master
* to complete its transaction. So make sure to adapt the timeout to accomodate for those cases if needed.
* A typical timeout would be 25ms (which is the maximum clock stretching allowed by the SMBus protocol),
* but (much) shorter values will usually also work.
*
* In the future, a timeout will be enabled by default, so if you require the timeout to be disabled, it is
* recommended you disable it by default using `setWireTimeoutUs(0)`, even though that is currently
* recommended you disable it by default using `setWireTimeout(0)`, even though that is currently
* the default.
*
* @param timeout a timeout value in microseconds, if zero then timeout checking is disabled
* @param reset_with_timeout if true then TWI interface will be automatically reset on timeout
* @param reset_on_timeout if true then TWI interface will be automatically reset on timeout
* if false then TWI interface will not be reset on timeout

*/
void TwoWire::setWireTimeout(uint32_t timeout, bool reset_with_timeout){
twi_setTimeoutInMicros(timeout, reset_with_timeout);
void TwoWire::setWireTimeout(uint32_t timeout, bool reset_on_timeout){
twi_setTimeoutInMicros(timeout, reset_on_timeout);
}

/***
Expand Down
10 changes: 9 additions & 1 deletion libraries/Wire/src/Wire.h
View file Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -25,11 +25,19 @@

#include <inttypes.h>
#include "Stream.h"
#include "utility/twi.h"

#define BUFFER_LENGTH 32

// WIRE_HAS_END means Wire has end()
#define WIRE_HAS_END 1
// WIRE_HAS_TIMEOUT means Wire has setWireTimeout(), getWireTimeoutFlag
// and clearWireTimeoutFlag()
#define WIRE_HAS_TIMEOUT 1

// When not configured, these settings are used for the timeout
#define WIRE_DEFAULT_TIMEOUT TWI_DEFAULT_TIMEOUT
#define WIRE_DEFAULT_RESET_ON_TIMEOUT TWI_DEFAULT_RESET_ON_TIMEOUT

class TwoWire : public Stream
{
Expand All @@ -55,7 +63,7 @@ class TwoWire : public Stream
void begin(int);
void end();
void setClock(uint32_t);
void setWireTimeout(uint32_t timeout = 25000, bool reset_with_timeout = false);
void setWireTimeout(uint32_t timeout = 25000, bool reset_on_timeout = false);
bool getWireTimeoutFlag(void);
void clearWireTimeoutFlag(void);
void beginTransmission(uint8_t);
Expand Down
10 changes: 5 additions & 5 deletions libraries/Wire/src/utility/twi.c
View file Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -51,9 +51,9 @@ static volatile uint8_t twi_inRepStart; // in the middle of a repeated start
// and twi_do_reset_on_timeout could become true
// to conform to the SMBus standard
// http://smbus.org/specs/SMBus_3_1_20180319.pdf
static volatile uint32_t twi_timeout_us = 0ul;
static volatile uint32_t twi_timeout_us = TWI_DEFAULT_TIMEOUT;
static volatile bool twi_timed_out_flag = false; // a timeout has been seen
static volatile bool twi_do_reset_on_timeout = false; // reset the TWI registers on timeout
static volatile bool twi_do_reset_on_timeout = TWI_DEFAULT_RESET_ON_TIMEOUT; // reset the TWI registers on timeout

static void (*twi_onSlaveTransmit)(void);
static void (*twi_onSlaveReceive)(uint8_t*, int);
Expand Down Expand Up @@ -451,13 +451,13 @@ void twi_releaseBus(void)
* Function twi_setTimeoutInMicros
* Desc set a timeout for while loops that twi might get stuck in
* Input timeout value in microseconds (0 means never time out)
* Input reset_with_timeout: true causes timeout events to reset twi
* Input reset_on_timeout: true causes timeout events to reset twi
* Output none
*/
void twi_setTimeoutInMicros(uint32_t timeout, bool reset_with_timeout){
void twi_setTimeoutInMicros(uint32_t timeout, bool reset_on_timeout){
twi_timed_out_flag = false;
twi_timeout_us = timeout;
twi_do_reset_on_timeout = reset_with_timeout;
twi_do_reset_on_timeout = reset_on_timeout;
}

/*
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8 changes: 8 additions & 0 deletions libraries/Wire/src/utility/twi.h
View file Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -34,6 +34,14 @@
#define TWI_BUFFER_LENGTH 32
#endif

#ifndef TWI_DEFAULT_TIMEOUT
#define TWI_DEFAULT_TIMEOUT 0
#endif

#ifndef TWI_DEFAULT_RESET_ON_TIMEOUT
#define TWI_DEFAULT_RESET_ON_TIMEOUT 0
#endif

#define TWI_READY 0
#define TWI_MRX 1
#define TWI_MTX 2
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