To avoid damage to the CP2102N device, a resistor divider MUST used in all power supply configurations when the VBUS pin is connected to a 5V USB VBUS supply. This is true whether the device is self-powered (i.e. VREGIN and VDD supplied from an external power supply) or the device is bus powered (i.e. VREGIN supplied from 5V USB VBUS and VDD is used as the 3.3 V internal regulator output.
There are two electrical specifications for this device that come into play in these situations. The first is the absolute maximum voltage requirement for all GPIO pins (including VBUS), given as VIO - 2.5 V in Table 3.10 on page 15 of the CP2102N datasheet, Rev. 1.2:
The second is the input high voltage for GPIO pins (including VBUS), which must be met for VBUS to accurately sense the device connection to USB. This spec is given in Table 3.7 on page 13 of the CP2102N datasheet, Rev. 1.2:
On devices with no VIO pin, then VIO = VDD for the purposes of the above specifications. The voltage divider requirement is necessary for self powered configurations to avoid exceeding the absolute maximum VBUS voltage specification in the case where the device is not powered but connected to USB. The voltage divider is necessary for bus-powered configuration in which the internal regulator is used in order to avoid damage to the device when VBUS = VREGIN = 5V but the regulator output (VDD) has not yet come up to 3.3 V.
The following diagrams show the correct use of the voltage divider with the recommended resistor values of 22.1 kOhm and 47.5 kOhm between USB VBUS supply and GND.
Self Powered mode:
Bus powered mode:
This information has been updated in the device datasheet and is reflected in the CP2102N datasheet, revision 1.2.
It is possible to use the CP2615 USB-to-Audio bridge with a codec that does not have an I2C interface. However, an incorrect configuration of the CP2615 can prevent correct operation.
Primarily of concern is that the CP2615, if it is programmed to send I2C data to the codec, will hang if no I2C device is present. This occurs because the CP2615 will retry any failed I2C transactions forever. To prevent this from occurring, clear all I2C Strings from the configuration of the CP2615.
Also make sure to disable [Enable Playback Mute via Register] to prevent the CP2615 from attempting to use I2C commands to mute the codec.
What is a Universal Windows Driver? Does Silicon Labs provide a Universal Windows Driver for CP210x?
A Universal Windows Driver is a single driver package that runs on all versions of Windows 10. Silicon Labs provides a Universal Windows Driver for CP210x. See VCP driver page: https://www.silabs.com/products/development-tools/software/usb-to-uart-bridge-vcp-drivers
CP2104的串口最大波特率2Mbps，波特率由48MHz系统主频分频而来，具体参考datasheet中的 Baud Rate Generation 章节。
CP2105的的standard串口最大波特率921.6kbps，而enhanced串口最大波特率2Mbps，波特率由48MHz系统主频分频而来，具体参考datasheet中的 Baud Rate Generation 章节。
CP2108的串口波特率最大2Mbps，波特率由系统主频80MHz分频而来，具体参考datasheet中的 Baud Rate Generation 章节。