User's Manual
Table Of Contents
- 1: Purpose
- 2: Scope
- 3: VAM-CM Overview
- 4: VAM-CM interfaces
- 4.1: Absolute maximum ratings
- 4.2: VAM Control interface description
- 4.2.1: System USB description
- 4.2.2: USIM interface description
- 4.2.3: VAM control UART interface description
- 4.2.4: Analog Audio interface description
- 4.2.5: Digital Audio interface description
- 4.2.6: Power Supply interface description
- 4.2.7: External VRTC Supply Functionality
- 4.2.8: Control and ID interface description
- 4.3: Radio interface description
- 4.4: VAM-CM Power Management Handling
- 4.5: Mechanical interface
- 4.6: Environmental conditions
- 5: Evaluation tools
DRAFT
4: VAM-CM interfaces
4.2.3.1:Voltage levels
The UART control bus is equipped with level shifter in VAM-CM board. This solution enables VAM to
adjust I/O voltage system by applying own V_io voltage to VAM control interface connector. Voltage
requirements for logic levels are shown in
Table 2
. More details in chapter Power Supply
interface description on page 16.
4.2.3.2:Interface control
UART control interface operation modes can be set using AT commands. More detailed information
about communication mode settings can be found in
Standard and Proprietary AT Commands
.
4.2.3.3:Data formats
UART control interface uses protocol with 8 data bits and 1 stop bit. Parity bits are not used in UART
communication. UART communication speed is 115200bps (bits per second).
4.2.4:Analog Audio interface description
The Analog audio interface is dedicated for simple audio interface for VAM terminals having analog
audio devices. Extensive care needs to be taken in analog audio interface design to avoid introducing
additional noise into audio signals.
Analog audio signals are located in VAM Control interface as described in
Table 6
.
PIN Signal Description
Parameter min typ max unit
#48 Audio Input Input resistance 50 60 70 ohm
Input capacitance 0 200 pF
#49 Audio Output Load resistance 14 16 ohm
Load capacitance 100 pF
peak output 0dBFs 1,5 Vpp
Peak output with 0dB gain settings
#50 GND Audio GND
Table 6. Analog audio interface pins
4.2.5:Digital Audio interface description
The Digital audio interface is dedicated for simple audio interfacing in cases where VAM terminal has
digital audio processing applied. The Digital audio interface is connected via level shifter circuit which
allows VAM terminal to determine the signal voltage level using V_io pin in VAM-CM system
connector.
Digital audio interface signals are located in VAM Control interface as described in
Table 7
Pin Signal In/Out Description
#29 dig_Au_FS In / Out Frame sync
#31 dig-Au_CLK In / Out Clock
#35 dig_Au_Dx Out Data out
14:GSPS Core Module 2.0 VAM-CM HW Description
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