dsPIC30F5015 UART pheripal停止工作

HiCPU:dsPIC30F5015 MPLAB XXC16:v1.26ICD3I有一个由两个处理器A和C组成的系统，它们通过半双工RS485线路相互通信。因为两边都是半双工的，所以大部分时间都在监听，但是C每半秒就发送一个“ping”。当系统启动时，A处理器对这个“ping”作出响应，并带有“ACK”消息（这也意味着A和B在发送时需要改变各自RS 465收发信机上的“方向”）。半双工发送和接收工作大约4秒钟，然后A停止对来自C的ping的响应。我可以看到C处理器上的发送和接收通过两个闪光的LED进行，闪光灯位于“C处理器RS 485收发信机内，即直接在C处理器UART传输上”。奇怪的是，如果我在第一个字节被写到U1TXREG之前在一行上设置断点（在A的源代码中，在A已经“停止”之后），A就发送响应（如果我继续按IDE中的运行按钮，A就继续发送消息），但是如果我设置了当A应该已经发送了所有字节时，A处理器不发送消息。为什么A发送只在启动时“工作”大约4秒钟，并且只有当我使用断点时才继续？有没有看到这个，有一些硅勘误表可以帮助我吗？ICD3“冻结外围设备”重载CPU吗？问候/斯特凡



      以下为原文

    Hi

CPU: dsPIC30F5015
MPLAB X
XC16: v1.26
ICD3


I have a system here consisting of two processors, A and C, which are communicating with each other via a half duplex RS485 line. Because of the half duplex both sides most of the time is listening but C sends a "pings" every half second.
The A processor respond on this "ping" with an "ACK" message (this also means that A and B need to change "direction" on their respective RS 465 transceiver when sending)

When the system starts the half duplex sending and receiving works for some 4 seconds and then the A stops responding on the ping from C.

I can see the transmit and receive on the C processor via two LED's that flashes that sits "inside the C processor RS 485 transceiver, that is directly on the C processor UART transmit and receive pins.


The strange thing is that if I set a break point (in the source code for A after A have "stalled") on a line just before the first byte is written to U1TXREG the A sends it respond (and if I continue to press the run button in the IDE the A continue to send messages)
but if I set a break point on a line when the A is supposed to have sent all bytes, the A processor is not sending the messages.

How come the A sending only "works" for some 4 seconds at start up and only continue if I use a break point?

Have any seen this, is there some silicon errata that might help me?
Do the ICD3 "freeze peripherals" ghosting the CPU ?

Regards

/Stefan