stm32m0 单片机按地址写长整数,地址必须是4的整数倍?

老麦Mac 提问时间：2016-5-13 18:42 /

一段以前用的很多的程序,以前在别的工程用过很多了(stm32 M3系列, 51单片机)
今天拿到m0单片机的工程里一运行就hard fault
找来找去似乎是这么个问题: 用指针往一个地址里写长整数数据, 这个地址必须是4的整数倍?
类似这样:
{
int* a;
int* b;
a = (int*)(0x20000410);
*a = 0; //okay
b = (int*)(0x20000421);
*b = 0; //hard fault
}
我用的是mdk5, 感觉应该是cpu什么模式没设置对吧? 应该怎么解决这个问题?
thx

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9个回答

老麦Mac 回答时间：2016-5-13 19:46:30

晕, 还真是这样?

Important
It is important to make sure the memory address accessed is aligned. For example, a word size
access can only be carried out on address locations when address bits[1:0] are set to zero, and
a half word size access can only be carried out on address locations when an address bit[0] is
set to zero. The Cortex-M0 processor does not support unaligned transfers. Any attempt at
unaligned memory access results in a hard fault exception. Byte-size transfers are always aligned
on the Cortex-M0 processor.

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