Smart Machine Smart Decision
SIM2000S_Hardware_Design_V1.00
28
2014-02-27
Table 9: VBUS operation voltage
Pin
Min
Typ
Max
Unit
VBUS
4.4
5
5.5
V
4.4.4
Software Upgrade and Debug
Customer could upgrade module’s firmware through USB.
If upgrading through USB port, it is necessary to power on SIM2000S first, and then connect VBUS, USB_DP,
USB_DM, and GND to PC. User should press the PWRKEY button before PC could detect USB port and could
communicate normally with USB_DP and USB_DM, then user should press the start button, the module will
enter download mode.
4.4.5
Multiplexing function of serial port and SD interface
If full modem is not necessary, it could be multiplexed with GPIO port, the details could be found in the
following table:
Table 10: Multiplexing function of serial port
Pin name
Pin number
Mode 0(default)
Mode 1
DTR
3
DTR
GPIO1
RI
4
RI
GPIO2
DCD
5
DCD
GPIO3
CTS
7
CTS
GPIO4
RTS
8
RTS
GPIO5
TXD
9
TXD
GPIO6
RXD
10
RXD
GPIO7
Note: Multiplexing function need different software supply. If user wants this function, the firmware must be
customized. Please contact SIMCom for more details.
Table 11: Multiplexing function of SD interface
Pin name
Pin number
Mode 0(default)
Mode 1
Mode 2
DTR
3
DTR
GPIO1
SDCC_CLK
DBG_TXD
27
DBG_TXD
GPIO12
SDCC_DATA_0
RI
4
RI
GPIO2
SDCC_DATA_1
DBG_RXD
28
DBG_RXD
GPIO13
SDCC_DATA_2
DCD
5
DCD
GPIO3
SDCC_DATA_3
PWM
35
PWM
GPIO18
SDCC_PWR_EN
STATUS
66
STATUS
GPIO32
SDCC_CMD
4.5.
RI behaviors
Table 12: RI behaviors