From 06aa13c350af0f3910b2d99303548f31a85c0d9c Mon Sep 17 00:00:00 2001
From: Damien George <damien.p.george@gmail.com>
Date: Fri, 16 Mar 2018 23:48:29 +1100
Subject: [PATCH] stm32/can: Use explicit byte extraction instead of casting to
 word ptr.

Casting the Data array to a uint32_t* leads to strict aliasing errors on
older gcc compilers.
---
 ports/stm32/can.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/ports/stm32/can.c b/ports/stm32/can.c
index b1bcd1c3e..5b5c4ad3f 100644
--- a/ports/stm32/can.c
+++ b/ports/stm32/can.c
@@ -222,8 +222,16 @@ STATIC int can_receive(CAN_TypeDef *can, int fifo, CanRxMsgTypeDef *msg, uint32_
     msg->RTR = box->RIR & 2;
     msg->DLC = box->RDTR & 0xf;
     msg->FMI = box->RDTR >> 8 & 0xff;
-    *(uint32_t*)&msg->Data[0] = box->RDLR;
-    *(uint32_t*)&msg->Data[4] = box->RDHR;
+    uint32_t rdlr = box->RDLR;
+    msg->Data[0] = rdlr;
+    msg->Data[1] = rdlr >> 8;
+    msg->Data[2] = rdlr >> 16;
+    msg->Data[3] = rdlr >> 24;
+    uint32_t rdhr = box->RDHR;
+    msg->Data[4] = rdhr;
+    msg->Data[5] = rdhr >> 8;
+    msg->Data[6] = rdhr >> 16;
+    msg->Data[7] = rdhr >> 24;
 
     // Release (free) message from FIFO
     *rfr |= CAN_RF0R_RFOM0;