Hardware interfaces
Version 8 dated 15.03.00
24
Siemens Information and Communication Products
Table 4-4
Timing characteristics of DAI
4.3.8
SIM card interface
In general the SIM interface is specified in GSM 11.11.
Note
: the M20 supports 3V SIM cards.
Notes
:
1
) All information provided on the SIM card interface complies with GSM 11.11 and 11.12.
Contacts C4, C6 and C8 are not provided by M20.
2
) When using a SIM card reader without a CCIN switch, SIM card removal must be avoided when voltage is applied to
the M20. This should be avoided by the mechanical integration of the SIM card reader in the application.
4.3.9
Power supply indicator
The power supply indicator is only used by the inbuilt MMI software. This allows the M20 MMI software to indicate the
actual base unit power supply status on the display.
Note
: this functionality is not available when controlling the M20 via the AT command interface.
t
94
VSDI hold time after VSCLK low
7
ns
t
95
VSDO delay after VSCLK high
0
15
ns
Signal
Function
I/O
Level
Comments
CCVCC
SIM card power supply
O
2.8 V
Contact C1
1)
CCRST
SIM card Reset
O
2.8 V
Contact C2
1)
CCIO
SIM card data in/out
I/O
2.8 V
Contact C7
1)
CCCLK
SIM card clock
O
2.8 V
Contact C3
1)
CCIN
SIM card Inserted switch
I
2.8 V
must be connected to GND, if SIM card reader does not
provide a CCIN switch.
2
)
GND
Ground
0 V
Contact C5
1)
Signal
Function
I/O
Level
Comments
GPCS
GP chip select
O
2.8 V
reserved
may be disconnected if unused
GPIO0
GP port pin 0
I
2.8 V
Supply source indicator (by mains or battery)
if unused, connect to a 10kOhm - 100 kOhm pull-down resistor
GPIO1
GP port pin 1
I
2.8 V
Battery load indicator (full or below warning level)
if unused, connect to a 10kOhm - 100 kOhm pull-down resistor
GPIO 1
GPIO 0
Description
0
0
Base unit supplied by mains, battery full (= normal state)
0
1
Base unit supplied by battery, battery full
1
0
Base unit supplied by mains, battery voltage below warning level
1
1
Base unit supplied by battery, battery voltage below warning level