TI中文支持网大牛们：
大家好，关于CC3100R11MRGCR WIFI模块有几个问题想咨询一下：
1、模块的SPI和UART的作用分别是什么？规格书上描述uart是用作程序升级。那我们需要实现MCU和WIFI模块的通信，在原理图设计上，SPI和UART是否都需要连接到MCU，UART接口是否需要接到外部接口作程序升级用？
2、datasheet推荐的设计参考，有两种电源方案，一种是3.3V，一种是1.85V。如果用3.3V的供电方案，接口的电压是3.3V的，而MCU的接口电压为1.8V，所以电路上比较麻烦。如果用1.85V的方案，则1.85V需求的电流高达900mA。在datasheet上没有找到芯片的内部结构图，我想问一下是否能够将VIN_DCDC_PA和VIN_IO的供电分开，VIN_DCDC_PA供3.3V，VIN_IO供1.8V。
PEI ZENG：
回复 Albin Zhang:
谢谢AZ，那个我咨询了下，是只能接单路电源的，不能接多路电源。现在还有个问题，在datasheet的第一页描述中有说CC3100是具有内部振荡器的40MHz时钟。 但是在规格书里没有找到任何的内部振荡器的说明。麻烦AZ帮忙了解一下，谢谢
Terry Han：
回复 PEI ZENG:
数据手册上，CC3100内部带有internal oscillators，但是外部还要增加一个40MHz的晶振，详细的介绍如下，
A fast clock running at 40 MHz is used by the device for the internal processor and the WLAN subsystem
The device features internal oscillators that enable the use of cheaper crystals rather than dedicated TCXOs for these clocks.
<1>The RTC can also be fed externally to provide reuse of an existing clock on the system and reduce overall cost.
The CC3200 device also incorporates an internal crystal oscillator to support a crystal-based fast clock. The XTAL is fed directly between WLAN_XTAL_P (pin 23) and WLAN_XTAL_N (pin 22) with suitable loading capacitors.
<2>The CC3200 device can accept an external TCXO/XO for the 40-MHz clock. In this mode of operation, the clock is connected to WLAN_XTAL_P (pin 23). WLAN_XTAL_N (pin 22) is connected to GND. The external TCXO/XO can be enabled by TCXO_EN (pin 21) from the device to optimize the power consumption of the system. If the TCXO does not have an enable input, an external LDO with an enable function can be used. Using the LDO improves noise on the TCXO power supply.
