以下是关于AN5439关于外部晶体振荡器的摘录:
如果没有使用MHz或KHz ECO,ECO引脚上的外部时钟信号可以使用KHz或MHz的晶体输入引脚将外部时钟信号路由到ECO时钟网络上。这允许使用这些时钟网络代替时钟树中通常的DSI时钟网络。外部时钟可以通过KHz和MHz XTALIN引脚路由到该部分。XTALOUT引脚应该允许浮动。理想情况下,外部信号应该是轨到轨正弦或方波。如果信号的幅度太低,则它们不能被正确地翻译成数字信号。这些信号必须在ECOS的额定频率,在32.768 kHz或4-25兆赫。外部时钟也可以到部分使用GPIO路由。详情见an60631 PSoC 3和PSoC -®5lp时钟资源。
我想用MEMS振荡器为MHz的32kHz生态和生态。这听起来像我可以配合他们每个生态输入正确,但它不说我需要设置的创造者。它具有所有微调晶体如故障恢复,参数调整的幅度,并参考水平。有人知道我在这种情况下会用到什么设置吗?同时,它说它应该是轨到轨输入,但铁路是我们在谈论什么?我打算用5V只有一个或两个端口,但MEMS振荡器似乎是3.3V的最大多数时间。似乎为港口生态VDDIO引脚都不会有任何的影响由于引脚被用在一个不同的方式,对吗?我们将不胜感激。
以上来自于百度翻译
以下为原文
Here's an excerpt from AN54439 about external crystal oscillators:
Using an External Clock Signal on the ECO Pins
If the MHz or kHz ECO is not being used, an external clock signal may be routed onto the ECO clock nets using the kHz or MHz crystal input pins. This allows the use of these clock nets in place of the usual DSI clock net in the clock tree. External clocks can be routed into the part through the kHz and MHz XtalIn pins. The XtalOut pins should be allowed to float. Ideally, the external signals should be rail-to-rail sine or square waves. If the amplitude of the signals is too low, they may not be properly translated into digital signals. These signals must be within the frequency ra
tings of the ECOs, either at 32.768 kHz or 4-25 MHz.
External clocks can also be routed into the part using the GPIOs. For more details, see AN60631 - PSoC® 3 and PSoC 5LP Clocking Resources.
I want to use MEMS oscillators for both the MHz ECO and the 32khz ECO. It sounds like I can tie them right to the input of each ECO, but it doesn't say anything about how I would need to set it up in Creator. It has all the parameters for fine tuning the crystal such as fault recovery, amplitude adjustment, and reference levels. Anyone know what settings I would use in this case? Also, it says it should be a rail to rail input, but which rail are we talking about? I'm planning on using 5V for all but one or two ports, but the MEMS oscillators seem to be 3.3V max most of the time. It seems like the VDDIO for the port where the ECO pins are located would not have any effect since the pin is being used in a different mode, right? Some guidance would be greatly appreciated.