Software Upgrade And Debug; Multiplexing Function Of Serial Port And Sd Interface; Ri Behaviors - SIM Tech SIMCom SIM2000S Hardware Design

Table 9: VBUS operation voltage
Pin
VBUS
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
DTR
RI
DCD
CTS
RTS
TXD
RXD
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
DTR 3
DBG_TXD 27
RI 4
DBG_RXD 28
DCD 5
PWM 35
STATUS 66

4.5. RI behaviors

Table 12: RI behaviors
SIM2000S_Hardware_Design_V1.00
Min Typ
4.4 5
Pin number
3
4
5
7
8
9
10
Mode 0(default)
DTR
DBG_TXD
RI
DBG_RXD
DCD
PWM
STATUS
Max
5.5
Mode 0(default)
DTR
RI
DCD
CTS
RTS
TXD
RXD
Mode 1
GPIO1
GPIO12
GPIO2
GPIO13
GPIO3
GPIO18
GPIO32
28
Smart Machine Smart Decision
Unit
V
Mode 1
GPIO1
GPIO2
GPIO3
GPIO4
GPIO5
GPIO6
GPIO7
Mode 2
SDCC_CLK
SDCC_DATA_0
SDCC_DATA_1
SDCC_DATA_2
SDCC_DATA_3
SDCC_PWR_EN
SDCC_CMD
2014-02-27