10 串口设备的rx_fifo为RT_NULL为空，怎么改呢？

发布于 2022-09-28 15:20:53 浏览：1076 订阅该版

分散加载文件如下

```c
LR_IROM1 0x08000000 0x00100000  {    ; load region size_region
  ER_IROM1 0x08000000 0x00100000  {  ; load address = execution address
   *.o (RESET, +First)
   *(InRoot$$Sections)
   .ANY (+RO)
  }
  RW_IRAM1 0x20000000 0x00020000  {  ; RW data
   .ANY (+RW +ZI)
  }
  	   RW_IRAM2 0x10000000 0x00010000  { 
   main.o  (+RW +ZI) 
	screen_read.o  (+RW +ZI)  
	screen_write.o (+RW +ZI)
	;startup_stm32f407xx.o  (+RW +ZI)
	;drv_usart.o (+RW +ZI)
	;myiic.o  (+RW +ZI)
	}
}

```
其中具体的是
![screenshot_图片.png](https://oss-club.rt-thread.org/uploads/20220928/3cea0873657658f1a7d526de6d7f8b7d.png)

当前用了2个串口，一个buf是256，另一个是4096，只要开串口，就报这个断言错误
(rx_fifo != RT_NULL) assertion failed at function:rt_serial_open, line number:629 
注释掉一个串口，另一个串口也会报错，我把这3个放在了那个64KB的位置，计算一下，加起来也没有65536个字节啊，为什么总报错呢？
堆栈空间截图

![screenshot_图片.png](https://oss-club.rt-thread.org/uploads/20220928/5417bd0ea41ff51b84e1a5b38c8f47bb.png)
谢谢

------------

更新，发现缩小串口的buf，程序可以跑起来，这里4096改成10可以运行

![screenshot_图片.png](https://oss-club.rt-thread.org/uploads/20220928/dc8fa217d7eacbf02aff93a217715730.png.webp)
但是我对比了正常和不正常的map文件，差别非常小，没有发现哪个特别大，我应该怎么调呢

![screenshot_图片.png](https://oss-club.rt-thread.org/uploads/20220928/69c8b550cdea62cedf1ef545f91fdffc.png)

3 个回答

出出啊 2022-09-28

恃人不如自恃，人之为己者不如己之自为也

伊森亨特 2022-09-28

这家伙很懒，什么也没写！

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追加回复

伊森亨特 2022-09-28

这家伙很懒，什么也没写！

因为是rx fifo失败，申请空间的函数是

```c
rx_fifo = (struct rt_serial_rx_fifo*) rt_malloc (sizeof(struct rt_serial_rx_fifo) +
                serial->config.bufsz);
            RT_ASSERT(rx_fifo != RT_NULL);
```
调用这个函数

```c
RT_WEAK void *rt_malloc(rt_size_t size)
{
    rt_base_t level;
    void *ptr;

/* Enter critical zone */
    level = _heap_lock();
    /* allocate memory block from system heap */
    ptr = _MEM_MALLOC(size);
    /* Exit critical zone */
    _heap_unlock(level);
    /* call 'rt_malloc' hook */
    RT_OBJECT_HOOK_CALL(rt_malloc_hook, (ptr, size));
    return ptr;
}
```
然后这个宏定义在这，相当于初始化之后，有一个systemheap

```c
#define _MEM_INIT(_name, _start, _size) \
    system_heap = rt_smem_init(_name, _start, _size)
#define _MEM_MALLOC(_size)  \
    rt_smem_alloc(system_heap, _size)
```

![screenshot_图片.png](https://oss-club.rt-thread.org/uploads/20220928/59de4ef8d8b3bd1ef45f2eaff8e2b1ed.png.webp)
这里调用了rt_system_heap_init函数

![screenshot_图片.png](https://oss-club.rt-thread.org/uploads/20220928/0419654c770244d32812d7f2b37d5aca.png)
出现heapbegin heapend，找到board.h

```c
#define STM32_SRAM_SIZE        (128)
#define STM32_SRAM_END         (0x20000000 + STM32_SRAM_SIZE * 1024)

#if defined(__ARMCC_VERSION)
extern int Image$$RW_IRAM1$$ZI$$Limit;
#define HEAP_BEGIN      (&Image$$RW_IRAM1$$ZI$$Limit)
#elif __ICCARM__
#pragma section="CSTACK"
#define HEAP_BEGIN      (__segment_end("CSTACK"))
#else
extern int __bss_end;
#define HEAP_BEGIN      (&__bss_end)
#endif

#define HEAP_END        STM32_SRAM_END
```