QDK PIC24/dsPIC-XC16 - Quantum Leaps

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QDK PIC24/dsPIC-XC16 www.state-machine.com/pic (15) The QK-specific ISR exit starts with placing the current SR into the this_sr local variable, which the XC16 compiler decided to place in the w8 register. (16) The IPL bits from the current SR are right-shifted into w0. (17) All other SR bits, except the IPL bits in w0 are masked off in w0. (18-19) The bitmask (1
QDK PIC24/dsPIC-XC16 www.state-machine.com/pic void QK_onIdle(void) { Listing 10: QK_onIdle() callback for PIC24/dsPIC. #ifdef Q_SPY while (U2STAbits.UTXBF == 0U) { /* TX Buffer not full */ uint16_t b; QF_INT_DISABLE(); b = QS_getByte(); QF_INT_ENABLE(); if (b == QS_EOD) { /* End-Of-Data reached */ break; /* break out of the loop */ } U2TXREG = (uint8_t)b; /* stick the byte to TXREG for transmission */ } #elif defined NDEBUG Idle(); /* transition to Idle mode */ #endif } 4.4 Testing QK Preemption Scenarios The technique described in this section will allow you to use the MPLAB debugger to trigger an interrupt at any machine instruction and observe the preemptions it causes. The interrupt used for the testing purposes is the GPIOA interrupt (INTID == 0). The ISR for this interrupt is shown below: The DPP example application for the preemptive QK kernel includes special ISR (INT0 ISR) for convenient testing of various preemption scenarios, defined as follows: #define INT0_ISR_PRIO 6 QK_ISR(auto_psv) _INT0Interrupt() { static QEvt const eat_evt = { EAT_SIG, 0U, 0U }; _INT0IF = 0; QACTIVE_POST(AO_Table, &eat_evt, &l_INT0Interrupt); QK_ISR_EXIT(); /* inform QK about exiting the ISR */ } The INT0 ISR, is assigned priority 6, which is higher than the priority of the system clock tick ISR. Figure 10 shows how to trigger the INT0 interrupt from the MPLABX debugger. From the debugger you need to first open the “File Registers” window (menu View | File Registers) as shown in Figure 10. You scroll to the IFS0 register at address 0x0084. To trigger the INT0 interrupt you need to write 1 to the leastsignificant bit (bit #0) of the IFS0 register. Copyright © Quantum Leaps, LLC. All Rights Reserved. 23 of 35
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QDK PIC24/dsPIC-XC16 - Quantum Leaps

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