Recently I am considering to design a macro USB dongle for Android (as HID/CDC device). Due to its limited space, I am trying to find a USB micro which can operate without external crystal. I know Microchip/Cypress can do, but STM claims that USB has to work with external crystal.
Can I use IRC(4MHz) of KL24/25Z as clock source for USB OTG?
Allan
已解决! 转到解答。
It is impossible to use IRC for USB module because the internal reference clock does not have required accuracy which is strictly needed for peripheral USB.
Regard
Pavel