User's Manual
Table Of Contents
- GC864 Hardware User Guide
- APPLICABILITY TABLE
- 1. Introduction
- 2. Overview
- 3. GC864 Mechanical Dimensions
- 4. GC864-QUAD/PY Module Connections
- 5. Hardware Commands
- 6. Power Supply
- 7. Antenna
- 8. Logic Level Specifications
- 9. Serial Ports
- 10. Audio Section Overview
- 11. General Purpose I/O
- 11.1. GPIO Logic Levels
- 11.2. Using a GPIO Pad as INPUT
- 11.3. Using a GPIO Pad as OUTPUT
- 11.4. Using the RF Transmission Control GPIO4
- 11.5. Using the RFTXMON Output GPIO5
- 11.6. Using the Alarm Output GPIO6
- 11.7. Using the Buzzer Output GPIO7
- 11.8. Magnetic Buzzer Concepts
- 11.9. Using the Temperature Monitor Function
- 11.10. Indication of Network Service Availability
- 11.11. RTC Bypass Out
- 11.12. VAUX1 Power Output
- 12. DAC and ADC Section
- 13. Mounting the GC864-QUAD/PY on the Board
- 14. Packing System
- Conformity Assessment Issues
GC864 Hardware User Guide
1vv0300733 Rev.12 – 2009-06-04
10. Audio Section Overview
The Baseband chip was developed for the cellular phones, which needed two
separated amplifiers both in RX and in TX section.
A couple of amplifiers had to be used with internal audio transducers while the other
couple of amplifiers had to be used with external audio transducers.
To distinguish the schematic signals and the Software identifiers, two different
definitions were introduced, with the following meaning:
• internal audio transducers Æ
HS/MT
(from HandSet or MicroTelephone )
• external audio transducers Æ
HF
(from HandsFree )
Actually the acronyms have not the original importance.
In other words this distinction is not necessary, being the performances between the
two blocks like the same.
Only if the customer needs higher output power to the speaker , he has a constraint.
Otherwise the choice could be done in order to overcome the PCB design difficulties.
For these reasons we have not changed the HS and HF acronyms, keeping them in
the Software and on the schematics.
The Base Band Chip of the GC864Telit Module maintains the same architecture.
For more information refer to Telit document :
“
80000NT10007a Audio Settings Application Note
“.
10.1. Selection mode
Only one block can be active at a time , and the activation of the requested audio
path is done via hardware by
AXE
line or via software by
AT#CAP
command .
Moreover the Sidetone functionality could be implemented by the amplifier fitted
between the transmit path and the receive path, enabled at request in both modes.
Reproduction forbidden without Telit Communications S.p.A’s. written authorization - All Rights Reserved. Page 45 of 69