MCP2515数据手册中的振荡器起振定时器（OST）值出错怎么解决？

我刚才看到一个有趣的行为比较WaKIF中断有关晶体振荡。它似乎有两个阶段的唤醒。功率晶体，但不振荡（ChanSTAT= 0x24睡眠+ WAKIF）晶体振荡（ChanSTAT＝0x64侦听+WAKIF）正常模式（CANSTAT＝0x00正常）也许128个ToSC只在唤醒的第二阶段有效吗？？？？我希望这能帮助你帮助我！！！！当做，



      以下为原文

    I just saw an interesting behavior when comparing the WAKIF interrupt related to the crystal oscillation. It seems to have two stage in Wake Up.

• Power to crystal but not oscillating (CANSTAT = 0x24 Sleep + WAKIF)
  
• Crystal oscillating (CANSTAT = 0x64 Listen Only + WAKIF)
  
• Normal mode (CANSTAT = 0x00 Normal)
  

Maybe the 128 Tosc is only valid in the second stage of the wakeup???
 
I hope that will help you to help me!!!
 
Regards,
   Attached Image(s)

嗨，这是Microchip支持团队的第一个答案。我在等待更多的细节。---------------嗨，贾景晖，你好。你说得对。128ToSc适用于振荡器开始振荡的时刻。



      以下为原文

    Hi,
Here is the first answer from the Microchip support team. I'm waiting for more details.
-------------------
Hi Marc, 
Good Day. 
You're right. The 128Tosc applies at the moment the oscillator starts oscillating. 
Regards, 
MJ
-------------------
Regards,

感谢您报告您的支持票的结果。对于一个20MHz的振荡器来说，毫秒似乎有点长——我本来期望几百微秒最大。什么连接到复位引脚？是否有一个可以解释延迟的RC复位电路？



      以下为原文

    Thanks for reporting the results of your support ticket. A millisecond does seem a bit long for a 20MHz oscillator to get going - I would have expected a couple hundred microseconds max. What's connected to the Reset pin? Is there an RC reset circuit that could explain the delay?

谢谢你的回答，复位引脚直接连接到C的GPIO，当C准备就绪时它被强制高。在我的用例中，（总线活动唤醒中断），C已经准备好，模块永远不会复位（通过复位引脚或SPI复位命令EIDER）。



      以下为原文

    Thank you mbrowning for your answer,
 
The reset pin is directly connected to a GPIO of the µC and it's forced high when the µC is ready.
 
In my use case, (Bus Activity Wake-up Interrupt), the µC is ready and the module is never reset (eider by the reset pin or by SPI reset command)

嗨，这是Microchip支持团队的答案。嗨，贾景晖，请看我们的业务单元的响应。通常超过1ms的唤醒时间是可以接受的。客户有特殊的唤醒要求吗？也许在MCP2515 DS 56页底部列出的注释是有用的。客户可以尝试调谐RS和C1和C2以优化启动时间。不幸的是，不可能对振荡器启动作出一般性陈述。这必须在客户应用程序中进行测试。Microchip有很多应用程序，讨论振荡器的设计，见MCP2517FD FRM第13节的一个简短列表：http://WW1.Microchip .com……EVICEDOC/2000 5678A。



      以下为原文

    Hi, here is the answer from Microchip Support team.
 
Hi Marc,

Please see response from our business unit.

Usually wake up times of more than 1ms are acceptable. 
Does the customer have special wake up requirements?

Maybe the notes listed on the bottom of page 56 of the MCP2515 DS are helpful.
The customer could try to tune RS and C1 and C2 to optimize the start up time.

Unfortunately, it is not possible to make general statements regarding oscillator start up. This has to be tested inside the customer application.

Microchip has lots of application notes that discuss oscillator design, see MCP2517FD FRM section 13.0 for a short list:
http://ww1.microchip.com/...eviceDoc/20005678A.pdf

Regards,
MJ