外部的WDT连接到PIC32 MX150 F128B但不能编程UC

嗨，试试电阻，值在470到1kHMIN之间（WDT/RST信号引脚）和（上拉电阻，/MCLR引脚）。参见：MCP1316的数据表：图5-4：具有ICSP特性的PIC®微控制器的典型应用电路。迈西尔



      以下为原文

    Hi,
Try with Resistor, value between 470 to 1kOhm
between (WDT /RST signal pin) and (Pullup resistor , /MCLR pin).
See: Datasheet for MCP1316: 
FIGURE 5-4: Typical Application Circuit for PIC® Microcontroller with the ICSP™ Feature.
 
   Mysil

谢谢！我刚刚看到了。我看了4-19！



      以下为原文

    Thanks! I just saw it. I`ve watched 4-19!

嗨，又来了！还有一个问题。我注意到WDT引脚必须被驱动低，所以MPC1316可以开始工作。所以，如果我从来没有驱动WDT引脚低，根本不是开始！我怎么解决这个问题？我想确定WDT每次都在工作。我能把WDT连接到下拉电阻吗？所以，如果控制器不启动（我的主要担心），WDT重置它？我假设PIC引脚在电源上处于高阻抗状态！谢谢！



      以下为原文

    Hi, again! One more question. I`ve noticed the WDT pin has to be driven low so MPC1316 could start working. So if I never drive WDT pin low is doesn`t start at all! How can I fix this? I want to be sure WDT is working every time. 
Can I connected WDT to pull-down resistor? So if the controller doesn`t start(which my major worry), the WDT to reset it?! I assume the PIC pins are in high impedance state on power on!
Thanks!

嗨，又来了！还有一个问题。我注意到WDT引脚必须被驱动低，所以MPC1316可以开始工作。所以，如果我从来没有驱动WDT引脚低，根本不是开始！我怎么解决这个问题？我想确定WDT每次都在工作。我能把WDT连接到下拉电阻吗？所以，如果控制器不启动（我的主要担心），WDT重置它？我假设PIC引脚在电源上处于高阻抗状态！谢谢！



      以下为原文

    Hi, again! One more question. I`ve noticed the WDT pin has to be driven low so MPC1316 could start working. So if I never drive WDT pin low is doesn`t start at all! How can I fix this? I want to be sure WDT is working every time. 
Can I connected WDT to pull-down resistor? So if the controller doesn`t start(which my major worry), the WDT to reset it?! I assume the PIC pins are in high impedance state on power on!
Thanks!

嗨，WDT pin？我在MPC1316的数据表中找不到这样一个PIN。MPC1316数据表中有WDI引脚。这个引脚在MPC1316设备上有微弱的上拉。将弱拉上连接到一个弱下拉电阻，可能会导致一个未定义的逻辑信号电平，这是不好的。迈西尔



      以下为原文

    Hi,
WDT pin ?
I cannot find such a pin in datasheet for MPC1316.
There is WDI pin in MPC1316 datasheet.
This pin have weak pull-up in the MPC1316 device.
Connecting a weak pull-up to a weak pull down resistor, may cause a undefined logic signal level, which is not good.
 
   Mysil

好啊！我看见了！有没有办法解决这个问题？确保即使在没有微控制器的情况下，WDT也会在上电后开始反击。！



      以下为原文

    Ok! I saw it! Is there a way to fix this? To ensure WDT will start countering after power up, even without microcontroller?!

嗨，在我看来，MPC1316的目的是不干扰微控制器启动，直到微控制器确认它是第一次活着。在我的理解中，PIC32 MX没有达到主功能的主要原因是晶体振荡器不工作。配置位设置为启用IESO＝ON（启用双速启动），这将使程序达到主要，即使晶体振荡器不工作。也考虑使用故障安全时钟监视器：FCKSM＝CSEME时钟开关使能，FSCM在启动代码中有附加的可能性。在执行其他启动操作之前，有一个钩子在重置后调用函数。如果你提供这样的函数，它将在重置后立即调用。迈西尔



      以下为原文

    Hi,
Seem to me, that MPC1316 is designed to Not interfere with microcontroller startup,
until the microcontroller confirm that it is alive first time. 
 
In my understanding, the main reason for PIC32MX not reaching start of main() function, would be Crystal oscillator not working.
You may make sure that configuration bits are set to enable IESO = ON 
(Two-Speed Start-up is enabled), this will make program reach main, even if crystal oscillator is not working.
Also consider using FailSafe Clock Monitor:  FCKSM = CSECME Clock Switch Enable, FSCM Enabled


There is an additional possibility,
In Startup code, there is a hook to call a function after reset, before other startup actions are performed.
If you provide a function like this, it will be called immediately after Reset.
void  on_reset (void)
{                                        /* Change to correct bit for WDI pin connection. */
    LATBCLR = _LATB_LATB2_MASK;          /* Toggle the hardware watchdog first time here. */
    TRISBCLR = _TRISB_TRISB2_MASK;
//    Nop(); Nop(); Nop(); Nop();          /* WDI pulse 50 nanosecond minimum. */
//    TRISBSET = _TRISB_TRISB2_MASK;
}  
 
   Mysil

好啊！但只是为了记录！我可以通过在MCP1316和UC之间增加一个反相器来修复这个bug吗？我会在逆变器输入上加上一个上拉电阻，它应该把逆变器保持在0状态。谢谢！



      以下为原文

    Ok! But just for the record! Can I fix this bug by adding an inverter between MCP1316 and the uC? I`ll put an pull-up resistor on the inverter input which should hold the inverter out in 0 state. 
Thanks!