2 Replies Latest reply on Sep 30, 2019 11:49 PM by gisc_1091076

    Reset device with sleep and I2C !


      I development a firmware, with the Psoc 5, that it need to received data from the I2C when is in sleep. I have a problem, that casually the device resets. In the loop i execute only sleep function and i clear the Wdt. Inside of the loop i don't use the functions to receive from the i2c though the master send me the same the data through the i2c. if I unplug the cable manually, that i use for the i2c communication, the firmware does not reset. I have configured the I2C module in this mode:



      Slave address:0x23

      Implementation: fixed function

      Address decode:hardware



      And this is the sleep function:


      void    Sleep ( void )


          // Stop Global Interrupt

      CYGlobalIntDisable ;


          Enable_3_3V_Write ( OFF ) ;   


      PSoCBlockOFF ( ) ;

      InOutOFF ( ) ;


      Custom_Delay ( TIME_1_MS ) ;


      // Sleep and wait for PICU interrupt

      CyPmSaveClocks ( ) ;


          // Mi risveglio con il timer o quando ricevo dati dall'I2C


      CyPmRestoreClocks ( ) ;


      InOutON ( ) ;

      PSoCBlockON ( ) ;


      update_Global_Time_from_sleep ( ) ;


          Enable_3_3V_Write ( ON ) ;


          // Start Global Interrupt

      CYGlobalIntEnable ;


      // Aggiorno il watchdog

      CyWdtClear ( ) ;




      I have urgency to resolve the problem. Can you help me ?

        • 1. Re: Reset device with sleep and I2C !



          According to my understanding the reset is occurring due to Watchdog Timer (WDT).


          1) In the code you have used CyGlobalIntDisable; This will disable interrupts from I2C and WDT.


          2) The device is then sent to Sleep using the API: CyPmSleep ( PM_SLEEP_TIME_NONE , PM_ALT_ACT_SRC_CTW | PM_SLEEP_SRC_I2C ). However, since there is no interrupt from I2C due to interrupts being disabled the device will remain in Sleep.


          3) The  WDT counter increaments by  one whenever a WDT interrupt occurs. Since the interrupts are disabled the WDT interrupt will not occur. But the WDT Counter will increament by one each time the central timewheel crosses the programmed tap point. When the counter reaches three, WDT asserts a hardware reset to the device.


          You can try enabling the interrupts so that the device wakesup from Sleep and WDT is cleared.


          I have created two test projects to test this. In both the projects I have disabled the global interrupts. In the project with sleep api the device is reset after some time (noticed by the blinking of the led) since the Cywdtclear(); is not executed as the device does not wake from Sleep. However the project in which I have not sent the device to sleep, reset does not occur as the wdt is periodically cleared by the Cywdtclear(); api.


          Please let me know if this helps. In case this does not resolve you issue please attach you project so that we can recreate the issue at our side.


          Best Regards


          • 2. Re: Reset device with sleep and I2C !

            Good morning, with yours advices we have resolved. Thanks.