AirM2M_ESP8266 WiFi module user manual V3.2
Shanghai AirM2M Communication Technology Co., Ltd
http://www.airm2m.com
Page 13
For the 18 fixed pins, A6501S and A6501 are totally identically defined. The newly added pins S1---S6 ,
except “5V”, are defined in the same way as 5 of the fixed pins but the space between the added pins is
2.54mm. The purpose of leading out the 6 pins that are often used is to make it easy for debugging.
Details are as following:
Table 4
A6501S S1---S6 Pin definition
Main distinctions between A6501S and A6501 are
：
(1) One LDO is added
：
AMS1117, developer can use the 5V power of serial port line USB2TTL directly for
power supply ;
(2) 6 pins are added whose space between each other is 2.54mm
：
5V
、
GND
、
U1RXD
、
U1TXD
、
U1RTS
、
U1CTS;
(3)Shielding case is not welded in the developer’s versions of modules for easy developments.
(4)The dimension is added from 16mm*24mm*3.3mm
（
A6501
）
to 16mm*32mm*3.3mm
（
A6501S
）；
(5)USB2TTL Serial port line will be enough for debugging directly, no need for development board.
PIN
Function
Description
S1
GND
GND
S2
U1RTS
identical to PIN2
S3
U1CTS
identical to PIN1
S4
U1TXD
identical to PIN15
S5
U1RXD
identical to PIN14
S6
5V
module power supply
