Specifications

SIM900 AT Commands Set
SIM900_ATC_V1.01 153 23.06.2010
the GPIO level, otherwise the module will return
“ERROR”.
<GPIO> the GPIO you want to set.( it has relations with the
hardware, Please refer to the hardware manual)
<function> Only when <Operation> is set as 0, this option takes
effect.
0 set the GPIO to input.
1 set the GPIO to output
2 set the GPIO to keypad
<level> 0 set the GPIO low level
1 set the GPIO high level
Reference Note
Only GPIO1, GPIO2, GPIO3, GPIO4, GPIO6, GPIO7, GPIO8, GPIO9 can
b
e used as Keypad. And if one of them is set to gpio function, others will
be set to GPIO output and low level automatically.
6.2.46 AT+SPWM Generate the Pulse-Width-Modulation
AT+SPWM Generate the Pulse-Width-Modulation
Response
+SPWM: (1-2),(0-126),(0-100)
OK
Test Command
AT+SPWM=?
Parameters
See Write Command
Response
OK
ERROR
Write Command
AT+SPWM=<in
dex>,
<period>,<level>
Parameters
<index> integer type: the index number of PWM port, which value is
1-2
<period> value can be converted to frequency. The output frequency
equal to (26MHz/8)/(period+1)
<level> the PWM pulse high time which can be convert to pulse
duty factor
Reference
Note
z We have a 26MHz crystal oscillator. The frequency of PWM is
26/8=3.25Mhz.
z The equation of final frequency and <period> is this: 3.25/(period+1)
= frequency. If <period> is set to 100, we get a frequency: 3.25/101 =
32.178Khz.