update luat/demo/spi/air8000/spi_tf_wan/main.lua.

Signed-off-by: 梁健 <liangjian@airm2m.com>

luat/demo/spi/air8000/spi_tf_wan/main.lua

@@ -49,7 +49,7 @@ local function tf_wan_init()
     -- 使用较低的统一速度以兼容TF卡和CH390
     spi.setup(spi_id, pin_cs, 0, 0, 8, SPI_SPEED)
     gpio.setup(pin_cs, 1)
-    fatfs.mount(fatfs.SPI, "/sd", spi_id, pin_cs, SPI_SPEED)
+    fatfs.mount(fatfs.SPI, "/sd", spi_id, pin_cs, SPI_SPEED)     -- 初始化TF 卡的时候，带入片选GPIO
 
     local data, err = fatfs.getfree("/sd")
     if data then
@@ -136,7 +136,7 @@ local function tf_wan_init()
     -- socket.LWIP_ETH 网络适配器编号
     -- netdrv.CH390外挂CH390
     -- SPI ID 1, 片选 GPIO12
-    netdrv.setup(socket.LWIP_ETH, netdrv.CH390, {spi=1,cs=12})
+    netdrv.setup(socket.LWIP_ETH, netdrv.CH390, {spi=1,cs=12})    -- 初始化以太网的时候，带入片选GPIO
     netdrv.dhcp(socket.LWIP_ETH, true)
     
     log.info("tf_wan", "WAN口初始化完成")