Specifications

SIM7912&SIM7906 Hardware Design V1.02
www.simcom.com 19 / 85
V
MAX
=1.9V
V
MIN
=1.7V
For 3.0V
SIM:
V
MAX
=3.05V
V
MIN
=2.75V
automatically.
If unused, please keep
open
SIM1_DATA
29
DIO
P4
SIM1 card data signal,
which has been pulled
up to SIM1_VDD by a
20K resistor internally
SIM1_CLK
27
DO
P4
SIM1 clock signal
SIM1_RST
28
DO
P4
SIM1 reset signal
SIM1_DET
25
DI
P3
SIM1 card detect signal,
which need pulled up to
VDD_EXT by a 470K
resistor externally
SIM2_VDD
74
PO
For 1.8V
SIM:
V
MAX
=1.9V
V
MIN
=1.7V
For 3.0V
SIM:
V
MAX
=3.05V
V
MIN
=2.75V
Power supply for SIM2
card
SIM2_DATA
77
DIO
P4
SIM2 card data, which
has been pulled up to
SIM2_VDD by a 20K
resistor internally
SIM2_CLK
80
DO
P4
SIM2 clock signal
SIM2_RST
79
DO
P4
SIM2 reset signal
SIM2_DET
78
DI
P3
SIM2 card detect, which
need pulled up to
VDD_EXT by a 470KR
resistor externally
SPI interface
Pin name
Pin
No.
Electrical description
Description
Comment
SPI_CS_N
DO
P3
SPI chip select
SPI_CLK
DO
P3
SPI clock
SPI_MOSI
DO
P3
Master output slaver
input
SPI_MISO
DI
P3
Master input slaver
output
Main UART interface