User's Manual

GE866-DUAL Hardware User Guide
1VV0301051 Rev. 2 – 2014-04-07 7
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Mod. 0805 2011-07 Rev.2
7.3. GSM Antenna - installation Guidelines .................... 39
8. Logic levels specifications ................................. 40
8.1. Reset signal ............................................. 41
9. Serial Ports ................................................ 43
9.1. Modem Serial Port ........................................ 43
9.2. RS232 levels translation ................................. 46
10. Audio Section Overview ...................................... 48
10.1. MIC Connection ......................................... 48
10.2. EAR Connection ......................................... 48
10.3. Electrical Characteristics ............................. 50
10.3.1. Input lines .............................................. 50
10.3.2. Output lines ............................................. 51
11. General Purpose I/O ......................................... 52
11.1. GPIO Logic Levels ...................................... 53
11.2. Using a GPIO Pad as INPUT .............................. 54
11.3. Using a GPIO Pad as OUTPUT ............................. 54
11.4. Using the RF Transmission Control GPIO4 ................ 54
11.5. Using the RFTXMON Output GPIO5 ......................... 55
11.6. Using the ALARM/BUZZER output GPIO6 .................... 55
11.7. Magnetic Buzzer Concepts ............................... 57
11.7.1. Short Description ........................................ 57
11.7.2. Frequency Behaviour ...................................... 58
11.7.3. Power Supply Influence ................................... 58
11.7.4. Working Current Influence ................................ 58
11.8. STAT LED Indication of network service availability .... 59
11.9. SIMIN detect function .................................. 60
11.10. RTC Bypass out ......................................... 60
11.11. SIM Holder Implementation .............................. 60
12. DAC and ADC section ......................................... 61
12.1. DAC Converter .......................................... 61
12.1.1. Description .............................................. 61
12.1.2. Enabling DAC ............................................. 61