User's Manual
Table Of Contents
- Contents
- Figures
- Tables
- Document history
- Introduction
- Product concept
- GSM application interface
- GSM/GPRS operating modes
- Power supply
- Power up / down scenarios
- Automatic GPRS Multislot Class change
- Charging control of the GSM part
- Power saving
- Summary of state transitions (except SLEEP mode)
- RTC backup for GSM part of XT55/56
- Serial interfaces of the XT55/56 GSM part
- Audio interfaces
- SIM interface
- Control signals
- GPS application interface
- GSM and GPS antenna interfaces
- Electrical, reliability and radio characteristics
- Mechanics
- Reference approval
- Example applications
- List of parts and accessories
XT55/56 Hardware Interface Description
Confidential / Released
s
XT55/56_hd_v02.06a Page 92 of 125 17.12.2004
Function Signal name IO Signal form and level Comments
GSM_CCIN I
R
I
100kΩ
V
IL
max = 0.5V
V
IH
min = 2.15V at I = 20µA,
V
IH
max=3.3V at I = 30µA
GSM_CCRST O
R
O
47Ω
V
OL
max = 0.25V at I = 1mA
V
OH
min = 2.3V at I = -1mA
V
OH
max = 2.73V
GSM_CCIO IO
R
I
10kΩ
V
IL
max = 0.5V
V
IH
min = 1.95V, V
IH
max=3.3V
R
O
220Ω
V
OL
max = 0.4V at I = 1mA
V
OH
min = 2.15V at I = -1mA
V
OH
min = 2.55V at I = -20µA
V
OH
max = 2.96V
GSM_CCCLK O
R
O
220Ω
V
OL
max = 0.4V at I = 1mA
V
OH
min = 2.15V at I = -1mA
V
OH
max = 2.73V
GSM_CCVCC O
R
O
max = 5Ω
GSM_CCVCCmin = 2.84V,
GSM_CCVCCmax = 2.96V
Imax = -20mA
SIM interface
GSM_CCGND Ground
GSM_CCIN = high, SIM
card holder closed (no card
recognition)
Maximum cable length
200mm to SIM card holder.
All signals of SIM interface
are protected against ESD
with a special diode array.
Usage of GSM_CCGND is
mandatory.
GSM_RXD0 O
GSM_TXD0 I
GSM_CTS0 O
GSM_RTS0 I
GSM_DTR0 I
GSM_DCD0 O
GSM_DSR0 O
ASC0
interface
GSM_RING0 O
V
OL
max = 0.2V at I = 1mA
V
OH
min = 2.35V at I = -1mA
V
OH
max = 2.73V
V
IL
max = 0.5V
V
IH
min = 1.95V, V
IH
max=3.3V
GSM_DTR0, GSM_RTS0: Imax = -90µA
at V
IN
= 0V
GSM_TXD0: Imax = -30µA at V
IN
= 0V
First serial interface for AT
commands or data stream.
To avoid floating if output
pins are high-impedance,
use pull-up resistors tied to
GSM_VDD or pull-down
resistors tied to GND. See
Chapter 3.3.2.1.
If unused keep pins open.
GSM_RXD1 O
GSM_TXD1 I
GSM_CTS1 O
ASC1
interface
GSM_RTS1 I
V
OL
max = 0.2V at I = 1mA
V
OH
min = 2.35V at I = -1mA
V
OH
max = 2.73V
V
IL
max = 0.5V
V
IH
min = 1.95V, V
IH
max=3.3V
I
I
max = -90µA at V
IN
= 0V
Second serial interface for
AT commands.
To avoid floating if output
pins are high-impedance,
use pull-up resistors tied to
GSM_VDD or pull-down
resistors tied to GND. See
Chapter 3.3.2.1.
If unused keep pins open.
GSM_RFSDAI I
GSM_RXDDAI I
GSM_SCLK I
GSM_TFSDAI O
Digital audio
interface
GSM_TXDDAI O
V
OL
max = 0.2V at I = 1mA
V
OH
min = 2.35V at I = -1mA
V
OH
max = 2.73V
V
IL
max = 0.5V
V
IH
min = 1.95V, V
IH
max=3.3V
I
I
max = 330µA at V
IN
= 3.3V
If unused keep pins open.