From 238cda0b90c3ac4ae8acc7c298391b8d449d83a2 Mon Sep 17 00:00:00 2001 From: JF Date: Fri, 19 Jun 2020 22:10:30 +0200 Subject: [PATCH] Apply fix for errata 87 (FPU issue). --- src/FreeRTOS/port_cmsis_systick.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/src/FreeRTOS/port_cmsis_systick.c b/src/FreeRTOS/port_cmsis_systick.c index 58c51bb7..b2cc14cd 100644 --- a/src/FreeRTOS/port_cmsis_systick.c +++ b/src/FreeRTOS/port_cmsis_systick.c @@ -251,6 +251,14 @@ void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime ) else #endif { + // Fix ERRATA 87 (https://infocenter.nordicsemi.com/index.jsp?topic=%252Fcom.nordic.infocenter.sdk5.v11.0.0%252Findex.html&cp=4_0_0) + // Clear FPU interrupt before going to sleep. This prevent unexpected wake-up. + #define FPU_EXCEPTION_MASK 0x0000009F + /* Clear exceptions and PendingIRQ from the FPU unit */ + __set_FPSCR(__get_FPSCR() & ~(FPU_EXCEPTION_MASK)); + (void) __get_FPSCR(); + NVIC_ClearPendingIRQ(FPU_IRQn); + /* No SD - we would just block interrupts globally. * BASEPRI cannot be used for that because it would prevent WFE from wake up. */