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14
MTX-GTW II | 2017/12
MTX © by MATRIX ELECTRONICA S.L.U.
mtxm2m.com | [email protected]
1.1.3 COM1
The UART3 interface of the iMX6UL-IND/IOT drives the RS232 interface of the MTX-GTW II by default. The
ST ST3232EBDR is used as a driver.
iMX6UL
DB9 F
COM1
ST3232
Transfer rate:
Up to 250Kbit/s
Interface on module: AUART3
Handshake:
RTS/CTS or XON/XONFF
ESD protection:
±15kV human body model
The pin 6 of DB9 connector is used like a extra digital input signal active low. This signal is routed to GPIO
expander chip in order to read its state from iMX6UL-IND/IOT using I2C bus. The following figure shows
simple input schematic.
GPIO IN RS 1
DB9 PIN6
Ri113
+3V3
100K
Di13
Ri112
1K
BAT54C
COM1 female
5
9
4
8
3
7
2
6
1
IRS 2
DB TXD2
DB CTS2
DB RXD2
DB RTS2