SIM900D Hardware Design
Table9: AT Command usually used in Charge-only mode
AT command
Function
AT+CCLK
Set data and time of RTC
AT+CPOWD
Power down
AT+CBC
Indicated charge state and voltage
AT+CFUN
Start or close the protocol
Set AT command
“AT+CFUN =1
”, module
can be transferred from Charge-only mode to
Charging in normal mode. In Charge-only
mode, the default value is 0.
3.5.5 Charger requirements
Following is the requirements of charger for SIM900D.
- Simple transformer power plug
- Output voltage: 5.0V-6V
- Minimum supply current: 750mA
- A 10V peak voltage is allowed for maximum 1ms when charging current is switched off.
- A 1.6A peak current is allowed for maximum 1ms when charging current is switched on
3.6 Summary of State Transitions (except SLEEP mode)
The following figure shows how module enters one mode from another mode.
Figure13: Charge State Transition
SIM900D_Hardware Design_V1.04
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