Specifications

AT Command Set Reference
Ver. 1.00
GSM1308AT001 Page 235 Ver. 1.00 – 10/29/2008
4.4.5 $IOPULEN GPIO Pullup Enable
(continued)
Examples
AT$ IOPULEN =11111111000000000000
Enable pullup feature on GPIOs 1 and 3-8
and disable on GPIOs 9-20.
AT$ IOPULEN?
$IOPULEN: 0x000000111111111111
GPIOs 1 and 3-8 have the pullup feature
disabled. GPIOs 9-20 have it enabled.