串口似乎只收到了一个字节，信号量要如何用？

pswarfound

lpc2378串口发送收到的数据，线程代码是参考的网络转串口项目里的代码，用到了信号量，现在只能发送收到的第一个字符，要怎么改啊？

#include <rtthread.h>
#include "lpc23xx.h"
struct rt_semaphore rx_sem;
rt_device_t dev_uart1;

unsigned int usart_bytes_sent = 0;
unsigned int usart_bytes_recv = 0;

rt_err_t usart_rx_indicate(rt_device_t dev, rt_size_t size)
{
    while(size--)
    {
        rt_sem_release(&rx_sem);
    }
    return RT_EOK;
}

#define RX_BUF_SIZE 1024
static char rx_buf[RX_BUF_SIZE];
static short rx_buf_offset = 0;

void usart_rx_thread_entry(void *p)
{

    while( rt_sem_take(&rx_sem,RT_WAITING_FOREVER) == RT_EOK )
    {
        register rt_base_t temp;

        // if rj45 not connected, we should route data between 232 and 485.
      
            // we split rx_buf to 2 parts in order to save space.
            int len1;
            // Clear the semaphore.
            temp = rt_hw_interrupt_disable();
            rx_sem.value = 0;
            rt_hw_interrupt_enable(temp);
                // recv usart1
                //rt_sem_take(&tx1_sem,RT_WAITING_FOREVER);
                len1 = rt_device_read(dev_uart1,0,rx_buf,RX_BUF_SIZE/2);
                if( len1 )
                    dev_uart1->write(dev_uart1, 0, rx_buf, len1);
                else
                    rt_sem_release(&tx1_sem);
                                                                                      
                         //  rt_sem_release(&tx1_sem);  
                                  rt_sem_release(&rx_sem);

    }
    rt_kprintf("Error taking semaphore, usart rx exit!\n");
}

void rt_init_thread_entry(void *parameter)
{                    
    rt_thread_t usart_rx_thread;
       
    rt_sem_init(&rx_sem,"semrx",0,RT_IPC_FLAG_FIFO);
    rt_sem_init(&tx1_sem,"semtx0",1,RT_IPC_FLAG_FIFO);

    dev_uart1 = rt_device_find("uart1");
    if( dev_uart1 == RT_NULL )
    {
        rt_kprintf("uart1 not found!!\n");
        return;
    }
  
    rt_device_set_rx_indicate(dev_uart1,usart_rx_indicate);
   
    usart_rx_thread = rt_thread_create("urx",usart_rx_thread_entry, RT_NULL,1024, 3, 5);
    rt_thread_startup(usart_rx_thread);
}


/* 用户应用程序入口点 */
int rt_application_init()
{
        rt_thread_t init_thread;
        init_thread = rt_thread_create("init", rt_init_thread_entry, RT_NULL, 1024, 8, 5);
        rt_thread_startup(init_thread);
       return 0;   
}

fgcx

直接看书，太简单。