add lte gsm nb-IoT some description

docs/en/module/gsm.md

@@ -29,6 +29,8 @@ Power Operation:
 
 *The Global System for Mobile Communications (GSM) is a standard developed by the European Telecommunications Standards Institute (ETSI) to describe the protocols for second-generation (2G) digital cellular networks used by mobile devices such as mobile phones and tablets.*
 
+!> **M5Stack Fire** has occupied GPIO16 / 17 to connect with the PSRAM by default, it's conflict with TXD / RXD (GPIO16, GPIO17) of GSM module. Therefore, when using the GSM module with the M5Stack Fire, you might have to cut the TXD and RXD from GSM module and wire fly to another set of UART pin, if you gonna use the PSRAM.
+
 ## Product Features
 Product Feature:
 - Serial communication: Uart 16/17

docs/en/module/lte.md

@@ -22,6 +22,8 @@ M8321  is 4V power input, so in the hardware of LTE-4G module, we added a Bidire
 
 *In telecommunication, Long-Term Evolution (LTE) is a standard for wireless broadband communication for mobile devices and data terminals, based on the GSM/EDGE and UMTS/HSPA technologies. It increases the capacity and speed using a different radio interface together with core network improvements.*
 
+!> **M5Stack Fire** has occupied GPIO16 / 17 to connect with the PSRAM by default, it's conflict with TXD / RXD (GPIO16, GPIO17) of LTE module. Therefore, when using the LTE module with the M5Stack Fire, you might have to cut the TXD and RXD from LTE module and wire fly to another set of UART pin, if you gonna use the PSRAM.
+
 ## Product Features
 Product Feature:
 - Double Antenna

docs/en/module/nb-iot.md

@@ -33,6 +33,9 @@ Power Operation:
 
 *More info about NB-IoT: NarrowBand-Internet of Things (NB-IoT) is a standards-based low power wide area (LPWA) technology developed to enable a wide range of new IoT devices and services. NB-IoT significantly improves the power consumption of user devices, system capacity and spectrum efficiency, especially in deep coverage. Battery life of more than 10 years can be supported for a wide range of use cases.Supported by all major mobile equipment, chipset and module manufacturers, NB-IoT can co-exist with 2G, 3G, and 4G mobile networks. It also benefits from all the security and privacy features of mobile networks, such as support for user identity confidentiality, entity authentication, confidentiality, data integrity, and mobile equipment identification. NB-IoT focuses specifically on indoor coverage, low cost, long battery life, and high connection density. NB-IoT uses a subset of the LTE standard, but limits the bandwidth to a single narrow-band of 200kHz. It uses OFDM modulation for downlink communication and SC-FDMA for uplink communications*
 
+!> **M5Stack Fire** has occupied GPIO16 / 17 to connect with the PSRAM by default, it's conflict with TXD / RXD (GPIO16, GPIO17) of NB-IoT module. Therefore, when using the NB-IoT module with the M5Stack Fire, you might have to cut the TXD and RXD from NB-IoT module and wire fly to another set of UART pin, if you gonna use the PSRAM.
+
+
 ## Product Features
 - Serial communication: UART
 - Product Power in : 5V

docs/zh_CN/module/gps.md

@@ -26,7 +26,7 @@ M5Core与GPS模块之间使用UART通信协议，通过连接引脚**UART2 (GPIO
 
 <img src="assets/img/product_pics/module/module_gps_06.png" width="70%" height="70%">
 
-**M5Stack Fire** 中的 GPIO 16 / 17 默认与PSRAM连接，这使得GPS模块的TXD / RXD（GPIO16，GPIO17）与其产生冲突.因此，当你使用 M5Stack Fire 去驱动 GPS 模块时，你需要将 GPS 模块的 TXD 与 RXD 切断，然后通过飞线引至另一组 UART 引脚.
+!>**M5Stack Fire** 中的 GPIO 16 / 17 默认与PSRAM连接，这使得GPS模块的TXD / RXD（GPIO16，GPIO17）与其产生冲突.因此，当你使用 M5Stack Fire 去驱动 GPS 模块时，你需要将 GPS 模块的 TXD 与 RXD 切断，然后通过飞线引至另一组 UART 引脚.
 
 ## 产品特性
 

docs/zh_CN/module/gsm.md

@@ -14,6 +14,8 @@
 <img src="assets\img\product_pics\module\gsm\gsm_03.jpg" width="30%" height="30%"> <img src="assets\img\product_pics\module\gsm\gsm_04.jpg" width="30%" height="30%">
 
 
+!>**M5Stack Fire** 中的 GPIO 16 / 17 默认与PSRAM连接，这使得GSM模块的TXD / RXD（GPIO16，GPIO17）与其产生冲突.因此，当你使用 M5Stack Fire 去驱动 GSM 模块时，你需要将 GSM 模块的 TXD 与 RXD 切断，然后通过飞线引至另一组 UART 引脚.
+
 ## 产品特性
 
 - SIM卡类型: Nano

docs/zh_CN/module/lte.md

@@ -14,6 +14,8 @@
 
  <img src="assets\img\product_pics\module\lte\lte_03.jpg" width="30%" height="30%">
 
+!>**M5Stack Fire** 中的 GPIO 16 / 17 默认与PSRAM连接，这使得LTE模块的TXD / RXD（GPIO16，GPIO17）与其产生冲突.因此，当你使用 M5Stack Fire 去驱动 LTE 模块时，你需要将 LTE 模块的 TXD 与 RXD 切断，然后通过飞线引至另一组 UART 引脚.
+
 ## 产品特性
 
 - SIM卡类型: Nano
@@ -22,6 +24,7 @@
 - 板载扬声器信号输出接口
 - 板载USB测试点
 - 单路开关机按钮
+- 串行通信：Uart2 16/17
 - 工作温度范围：-40°C 至+ 85°C
 - 频段:
     LTE-TDD：B38/B39/B40/B41 

docs/zh_CN/module/nb-iot.md

@@ -24,6 +24,8 @@
 - GPIO26高电平模块复位
 
 
+!>**M5Stack Fire** 中的 GPIO 16 / 17 默认与PSRAM连接，这使得NB-IoT模块的TXD / RXD（GPIO16，GPIO17）与其产生冲突.因此，当你使用 M5Stack Fire 去驱动 NB-IoT 模块时，你需要将 NB-IoT 模块的 TXD 与 RXD 切断，然后通过飞线引至另一组 UART 引脚.
+
 ## 产品特性
 
 - SIM卡类型: Nano