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
9. Serial Ports
The serial port on the Telit GC864-QUAD/PY is the core of the interface between the
module and OEM hardware.
2 serial ports are available on the module:
• MODEM SERIAL PORT
• MODEM SERIAL PORT 2 (DEBUG)
9.1. MODEM SERIAL PORT
Several configurations can be designed for the serial port on the OEM hardware, but
the most common are:
• RS232 PC com port
• microcontroller UART @ 2.8V – 3V (Universal Asynchronous Receive
Transmit)
• microcontroller UART@ 5V or other voltages different from 2.8V
Depending from the type of serial port on the OEM hardware a level translator circuit
may be needed to make the system work. The only configuration that does not need a
level translation is the 2.8V UART.
The serial port on the GC864-QUAD/PY is a +2.8V UART with all the 7 RS232 signals.
It differs from the PC-RS232 in the signal polarity (RS232 is reversed) and levels. The
levels for the GC864-QUAD/PY UART are the CMOS levels:
Absolute Maximum Ratings –Not Functional
Parameter Min Max
Input level on any
digital pad when on
-0.3V +3.6V
Input voltage on
analog pads when on
-0.3V +3.0 V
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