Hardware Guide
Table Of Contents
- Introduction
- 2. Overview
- 3. GE865 Mechanical Dimensions
- 4. GE865 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. Indication of network service availability
- 11.9. RTC Bypass out
- 11.10. External SIM Holder Implementation
- 12. DAC and ADC section
- 13. Mounting the GE865 on your Board
- 14. Packing system
- 15. Conformity Assessment Issues
- 17. Document History
GE865 Hardware User Guide
1vv0300799 Rev.15– 2012-04-23
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved page 16 of 77
5. Hardware Commands
5.1. Turning ON the GE865
To turn on the GE865 the pad ON# must be tied low for at least 1 second and then released.
When the power supply voltage is lower than 3.4V the pad ON# must be tied low at least 5
seconds.
The maximum current that can be drained from the ON# pad is 0,1 mA.
A simple circuit to do it is:
NOTE:
Don't use any pull up resistor on the ON# line, it is internally pulled up. Using pull up resistor
may bring to latch up problems on the GE865 power regulator and improper power on/off of the
module. The line ON# must be connected only in open collector configuration.
NOTE:
In this document all the lines that are inverted, hence have active low signals are labelled with a
name that ends with”#" or with a bar over the name.
TIP:
To check if the device has powered on, the hardware line PWRMON should be monitored. After
900ms the line raised up the device could be considered powered on.
NOTE:
It is mandatory to avoid sending data to the serial ports during the first 200mS of the module
start-up.