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 93 of 125 17.12.2004
Function Signal name IO Signal form and level Comments
GSM_EPP2 O
GSM_EPN2 O
V
O
max = 3.7Vpp
See also Table 32.
The audio output is
balanced and can directly
operate an earpiece.
If unused keep pins open.
GSM_EPP1 O
GSM_EPN1 O
V
O
max = 3.7Vpp
See also Table 32.
Balanced audio output. Can
be used to directly operate
an earpiece.
If unused keep pins open.
GSM_MICP1 I
GSM_MICN1 I
R
I
50kΩ differential
V
I
max = 1.03Vpp
See also Table 33.
Balanced microphone input.
To be decoupled with 2
capacitors (C
K
= 100nF), if
connected to a microphone
or another device.
If unused keep pins open.
GSM_MICP2 I
Analog audio
interfaces
GSM_MICN2 I
R
I
= 2kΩ differential
V
I
max = 1.03Vpp
See also Table 33.
Balanced microphone input.
Can be used to directly feed
an active microphone.
If used for another signal
source, e.g. op amp, to be
decoupled with capacitors.
If unused keep pins open.
Antenna
power
GPS_VANT I Max. 8V DC
Max. 25 mA
Power supply for active
antenna; in case of 3V
antenna can be connected
to GPS_VCC_RF
Internal
antenna
power
GPS_VCC_RF O Typ.: 3.0V ±5% DC
Max: 25 mA
Regulates 3V output for
feeding a 3V active GPS
antenna
GPS power GPS_VCC I Typ.: 3.3V ±5% DC
Typ. 80 mA (without feeding
GPS_VCC_RF)
50 mV ripple
Digital Input /
Output
GPS_GPIO0 I/O CMOS 3.3V DC level See Chapter 4.5
Digital Input /
Output
GPS_GPIO1 I/O CMOS 3.3V DC level See Chapter 4.5
Digital Input /
Output
GPS_GPIO3 I/O CMOS 3.3V DC level See Chapter 4.5
Digital Input /
Output
GPS_GPIO4 I/O CMOS 3.3V DC level Output for Trickle Power
mode. Connect externally to
GPS_RFPC1. Usable as
LED control output, see
Chapter 4.7
Digital Input /
Output
GPS_GPIO5 I/O CMOS 3.3V DC level See Chapter 4.5
Digital Input /
Output
GPS_GPIO6 I/O CMOS 3.3V DC level See Chapter 4.5
Digital Input /
Output
GPS_GPIO7 I/O CMOS 3.3V DC level See Chapter 4.5
Digital Input /
Output
GPS_GPIO8 I/O CMOS 3.3V DC level Output for Trickle Power
mode. Connect externally to
GPS_RFPC0. Usable as
LED control output, see
Chapter 4.7
Digital Input /
Output
GPS_GPIO10 I/O CMOS 3.3V DC level See Chapter 4.5
Digital Input /
Output
GPS_GPIO13 I/O CMOS 3.3V DC level See Chapter 4.5
Explanation of signal names:
P = positive, N = negative