diff --git a/src/portable/ti/msp430x5xx/dcd_msp430x5xx.c b/src/portable/ti/msp430x5xx/dcd_msp430x5xx.c index c3b3b240..f1d350dc 100644 --- a/src/portable/ti/msp430x5xx/dcd_msp430x5xx.c +++ b/src/portable/ti/msp430x5xx/dcd_msp430x5xx.c @@ -623,7 +623,18 @@ void dcd_int_handler(uint8_t rhport) handle_setup_packet(); } - uint16_t curr_vector = USBVECINT; + // Workaround possible bug in MSP430 GCC 9.3.0 where volatile variable + // USBVECINT is read from twice when only once is intended. The second + // (garbage) read seems to be triggered by certain switch statement + // configurations. + uint16_t curr_vector; + #if __GNUC__ > 9 || (__GNUC__ == 9 && __GNUC_MINOR__ > 2) + asm volatile ("mov %1, %0" + : "=r" (curr_vector) + : "m" (USBVECINT)); + #else + curr_vector = USBVECINT; + #endif switch(curr_vector) {