Neo_M680 GPRS Module Hardware User Guide
Copyright © Neoway Technology Co., Ltd
20
Upon receipt of the unsolicited messages, the host MCU should pull DTR high firstly, otherwise the
module will resume sleep mode shortly. And then the host MCU can process the voice call, received
data, or SMS. After processing is finished, pull DTR low again to put the module into sleep mode.
4.
Pull DTR high, the module will exit from sleep mode actively, and furthermore enable the UART.
Thus the voice call, received data, or SMS can be processed through UART. After processing
finished pull it low again, to take the module back to sleep mode.
3.4.2 RING Signal Indicator
Calling: Once a voice call is coming, UART output "RING" character strings and meanwhile the
RING pin outputs 250 ms low pulses at 4s period. After the call is answered, the high level restores.
Figure 3-16
RING indicator for incoming call
SMS: Upon receipt of SMS, the module outputs one 600 ms low pulse.
Figure 3-17
RING indicator for SMS
3.5
SIM Card Interface
Table 3-5
SIM Card Interface
Signal
I/O
Function Description
Remarks
VSIM
P
SIM card power supply output
1.8V/3.0V
SIM_CLK
DO
SIM card clock output
SIM_RST
DO
SIM card reset output
SIM_DATA
DI/O
SIM card data IO
Internal pull-up
M680 supports 3.0 V and 1.8 V SIM cards. VSIM supplies power for SIM card with 30 mA.
SIM_DATA is internally pulled up by a resistor. External pull-up resistor is not needed.
4s
250 ms
250 ms
600 ms
