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Telit Wireless Solutions UC864-G, Hardware User'S Manual

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Telit Wireless Solutions UC864-G Hardware User'S Manual Download Page 41

 
 
 
 

 

 

UC864-G Hardware User Guide 

 DRAFT

 - 29/10/07    

  

Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved 

 

page 41 of 66 

 

10.4   Microphone Biasing 

The electret microphones usually need a biasing voltage to work properly. Refer to your microphone 
provider for the characteristics required. 
 

NOTE: The microphones have a hot wire were the positive biasing must be connected. Usually 
it is indicated by a + symbol or a red point. If the polarity of the bias is reversed, then the 
microphone will not work properly. For this reason be sure to respect the mic. biasing polarity.  

 

10.4.1  Balanced Microphone Biasing 

 
The balanced microphone bias voltage should be obtained from a dedicated voltage regulator, in order 
to eliminate the noise present on the power lines. This regulator can be the same for all the audio 
paths. The microphone should be supplied from a capacitor multiply circuit. 
For example a circuit for the balanced microphone biasing can be: 
 

Summary of Contents for UC864-G

Page 1: ...UC864 G Hardware User Guide DRAFT 29 10 07 ...

Page 2: ... Hardware User Guide DRAFT 29 10 07 Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 2 of 66 This document is relating to the following products UC864 G ...

Page 3: ... 5 2 1 1 5V input Source Power Supply Design Guidelines 18 5 2 1 2 12V input Source Power Supply Design Guidelines 19 5 2 1 3 Battery Source Power Supply Design Guidelines 21 5 2 1 4 Battery Charge control Circuitry Design Guidelines 21 5 2 2 Thermal Design Guidelines 23 5 2 3 Power Supply PCB layout Guidelines 24 6 Antenna 25 6 1 GSM WCDMA Antenna Requirements 25 6 2 GSM WCDMA Antenna Installatio...

Page 4: ...ise Filtering 51 11 4 Handset Earphone Design 52 11 5 Hands Free Earphone Low Power Design 53 11 6 Car Kit Speakerphone Design 54 12 General Purpose I O 55 12 1 Logic level specifications 56 12 2 Using a GPIO Pad as INPUT 57 12 3 Using a GPIO Pad as OUTPUT 57 12 4 Using the RFTXMON Output GPIO5 57 12 5 Using the Alarm Output GPIO6 57 12 6 Using the Buzzer Output GPIO7 58 12 7 Indication of network...

Page 5: ...UC864 G Hardware User Guide DRAFT 29 10 07 Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 5 of 66 14 Document Change Log 66 ...

Page 6: ...egoing Telit does not make any warranty as to the information contained herein and does not accept any liability for any injury loss or damage of any kind incurred by use of or reliance upon the information Telit disclaims any and all responsibility for the application of the devices characterized in this document and notes that the application of the device must comply with the safety standards o...

Page 7: ...n user application shall be done according to the design rules described in this manual IT L integrazione del modulo cellulare GSM GPRS EGPRS WCDMA HSDPA UC864 G all interno dell applicazione dell utente dovrà rispettare le indicazioni progettuali descritte in questo manuale DE Die integration des UC864 G GSM GPRS EGPRS WCDMA HSDPA Mobilfunk Moduls in ein Gerät muß gemäß der in diesem Dokument bes...

Page 8: ... 29 10 07 Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 8 of 66 2 Mechanical Dimensions The Telit UC864 G module overall dimensions are Length 45 mm Width 30 mm Thickness 4 8mm ...

Page 9: ...utput phase Audio 10 EAR_HF AO Hands free ear output phase Audio 11 EAR_MT AO Handset earphone signal output phase Audio 12 EAR_MT AO Handset earphone signal output phase Audio 13 MIC_HF AI Hands free microphone input phase nominal level 3mVrms Audio 14 MIC_HF AI Hands free microphone input phase nominal level 3mVrms Audio 15 MIC_MT AI Handset microphone signal input phase nominal level 50mVrms Au...

Page 10: ...used to sense whether a peripheral device is connected and determine the peripheral type a host or a peripheral Analog 36 PCM_CLOCK I O PCM clock out CMOS 2 6V DAC and ADC 37 ADC_IN1 AI Analog Digital converter input A D 38 ADC_IN2 AI Analog Digital converter input A D 39 ADC_IN3 AI Analog Digital converter input A D 40 DAC_OUT AO Digital Analog converter output D A PDM Miscellaneous Functions 45 ...

Page 11: ...GPIO CMOS 2 6V 67 TGPIO_08 I O Telit GPIO8 Configurable GPIO CMOS 2 6V 68 TGPIO_06 ALARM I O Telit GPIO6 Configurable GPIO ALARM CMOS 2 6V 70 TGPIO_01 I O Telit GPIO1 Configurable GPIO CMOS 2 6V 71 TGPIO_17 PCM_SYNC I O Telit GPIO17 Configurable GPIO PCM Sync CMOS 2 6V 72 TGPIO_21 I O Telit GPIO21 Configurable GPIO CMOS 2 6V 73 TGPIO_07 BUZZER I O Telit GPIO7 Configurable GPIO Buzzer CMOS 2 6V 74 ...

Page 12: ...upply 3 VBATT Main power supply 4 VBATT Main power supply 5 GND Ground 6 GND Ground 7 GND Ground 46 GND Ground 25 C103 TXD Serial data input TXD from DTE 26 C104 RXD Serial data output to DTE 31 C105 RTS Input for Request to send signal RTS from DTE 53 ON OFF Input command for switching power ON or OFF toggle command 54 RESET Reset input 3 1 1 UC864 G Antenna connector The UC864 G module is equipp...

Page 13: ...to the USB_VBUS pin before the module turns on To check if the UC864 G has powered on the hardware line PWRMON should be monitored When PWRMON goes high the module has powered on 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 UC864 G power regulator and improper power on off of the module The line ON must b...

Page 14: ...lit Communications S p A written authorization All Rights Reserved page 14 of 66 For example 1 Let s assume you need to drive the ON pad with a totem pole output of a 3 5 V microcontroller uP_OUT1 2 Let s assume you need to drive the ON pad directly with an ON OFF button 1s 10k ...

Page 15: ...t you MUST cut off supplying power to the USB_VBUS pin then the pad ON must be tied low for at least 2 seconds and then released The same circuitry and timing for the power on shall be used The device shuts down after the release of the ON pad NOTE To turn OFF UC864 G first of all you MUST cut off supplying power to the USB_VBUS or the module does not turn off TIP To check if the device has powere...

Page 16: ...oper functioning of the module The line RESET must be connected only in open collector configuration TIP The unconditional hardware Restart should be always implemented on the boards and software should use it as an emergency exit procedure For example 1 Let s assume you need to drive the RESET pad with a totem pole output of a 3 5 V microcontroller uP_OUT2 Reset Signal Operating levels Signal Min...

Page 17: ...MA mode TBD Average current during idle Power Saving disabled during WCDMA mode TBD Average current during Power Saving with CFUN 5 during GSM GPRS mode TBD Average current during idle Power Saving disabled during GSM GPRS mode 37mA Average GPS current during Power Saving TBD In GSM GPRS mode RF transmission is not continuous and it is packed into bursts at a base frequency of about 216 Hz and the...

Page 18: ...5 2 1 1 5V input Source Power Supply Design Guidelines The desired output for the power supply is 3 8V hence there s not a big difference between the input source and the desired output and a linear regulator can be used A switching power supply will not be suited because of the low drop out requirements When using a linear regulator a proper heat sink shall be provided in order to dissipate the p...

Page 19: ... transient response This allows the regulator to respond quickly to the current peaks absorption For car PB battery the input voltage can rise up to 15 8V and this should be kept in mind when choosing components all components in the power supply must withstand this voltage A Bypass low ESR capacitor of adequate capacity must be provided in order to cut the current absorption peaks a 100µF tantalu...

Page 20: ...UC864 G Hardware User Guide DRAFT 29 10 07 Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 20 of 66 ...

Page 21: ...s for Li Ion Batteries can be divided into 4 phases Qualification and trickle charging Fast charge 1 constant current Final charge constant voltage or pulsed charging Maintenance charge The qualification process consists in a battery voltage measure indicating roughly its charge status If the battery is deeply discharged that means its voltage is lower than the trickle charging threshold then the ...

Page 22: ...h again few hundreds of ms and a duty cycle around 5 or less This last phase is not implemented in the UC864 G internal charging algorithm so that the battery once charged is left discharging down to a certain threshold so that it is cycled from full charge to slight discharge even if the battery charger is always inserted This guarantees that anyway the remaining charge in the battery is a good p...

Page 23: ... for 930mA maximum RMS current or even could be the simple chip package no heat sink Moreover in the average network conditions the device is requested to transmit at a lower power level than the maximum and hence the current consumption will be less than the 930mA being usually around 150mA For these reasons the thermal design is rarely a concern and the simple ground plane where the power supply...

Page 24: ...nt peaks frequency of 216 Hz that will reflect on all the components connected to that supply introducing the noise floor at the burst base frequency For this reason while a voltage drop of 300 400 mV may be acceptable from the power loss point of view the same voltage drop may not be acceptable from the noise point of view If your application doesn t have audio interface but only uses the data fe...

Page 25: ...for this transmitter must be installed to provide a separation distance of at least 20 cm from all persons and must not be co located or operating in conjunction with any other antenna or transmitter End Users must be provided with transmitter operation conditions for satisfying RF exposure compliance OEM integrators must ensure that the end user has no manual instructions to remove or install the...

Page 26: ...an extremely poor GPS reception and also the combination antenna requires additional diplexer and adds a loss in the RF route GPS ANTENNA REQUIREMENTS Frequency range 1575 42 MHz GPS L1 band Bandwidth 2 MHz Gain TBD Impedance 50 ohm Amplification TBD Supply voltage Must accept from 3 to 4V DC Current consumption TBD If the device is developed for the US market and or Canada market it shall comply ...

Page 27: ...G interface circuits For 2 6V CMOS signals Absolute Maximum Ratings Not Functional UC864 G Parameter Min Max Input level on any digital pin when on 0 3V 3 0V Input voltage on analog pins when on 0 3V 3 0 V Operating Range Interface levels UC864 G Level Min Max Input high level 2 0V 2 9 V Input low level 0 3V 0 6V Output high level 2 2V 2 6V Output low level 0V 0 35V For 2 0V signals Operating Rang...

Page 28: ...rmally shutting down the device but only as an emergency exit in the rare case the device remains stuck waiting for some network response The RESET is internally controlled on start up to achieve always a proper power on reset sequence so there s no need to control this pin on start up It may only be used to reset a device already on that is not responding to any command NOTE do not use this signa...

Page 29: ...er 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 doesn t need a level translation is the 2 8V UART The serial port on UC864 G is a 2 6V UART with all the 7 RS232 signals It differs from the PC RS232 in the signal polarity RS232 is reversed and leve...

Page 30: ... DSR dsr_uart 27 Data Set Ready Output from the UC864 G that indicates the module is ready 7 RTS rts_uart 31 Request to Send Input to the UC864 G that controls the Hardware flow control 8 CTS cts_uart 28 Clear to Send Output from the UC864 G that controls the Hardware flow control 9 RI ri_uart 30 Ring Indicator Output from the UC864 G that indicates the incoming call condition NOTE According to V ...

Page 31: ...ator from the 0 3V UART level to the RS232 level while the receiver is the translator from RS232 level to 0 3V UART In order to translate the whole set of control lines of the UART you will need 5 drivers 3 receivers NOTE The digital input lines working at 2 6V CMOS have an absolute maximum input voltage of 3 0V therefore the level translator IC shall not be powered by the 3 8V supply of the modul...

Page 32: ...n forbidden without Telit Communications S p A written authorization All Rights Reserved page 32 of 66 An example of level translation circuitry of this kind is The RS232 serial port lines are usually connected to a DB9 connector with the following layout ...

Page 33: ...t from 2 6 3V then a circuitry has to be provided to adapt the different levels of the two set of signals As for the RS232 translation there are a multitude of single chip translators For example a possible translator circuit for a 5V TRANSMITTER RECEIVER can be TIP This logic IC for the level translator and 2 8V pull ups not the 5V one can be powered directly from PWRMON line of UC864 G Note that...

Page 34: ...G input lines connected to open collector outputs in order to avoid latch up problems on UC864 G Care must be taken to avoid latch up on UC864 G and the use of this output line to power electronic devices shall be avoided especially for devices that generate spikes and noise such as switching level translators micro controllers failure in any of these condition can severely compromise the UC864 G ...

Page 35: ...Mbps Hence you need to interface UC864 G to your applications in full speed 12Mbits s mode You can use USB for the following purposes communication with external peripheral devices debug monitor USB Pin No Signal UC864 G Pad No Usage 1 USB_VBUS 48 Power supply for the internal USB transceiver This pin is configured as an analog input or an analog output depending upon the type of peripheral device...

Page 36: ...nction HF lines is suited for hands free function car kit These two blocks can be active only one at a time selectable by AXE hardware line or by AT command The audio characteristics are equivalent in transmit blocks but are different in the receive ones and this should be kept in mind when designing Differential Line Out Drivers Fully Differential Power Buffers EXTERNAL AMPLIFIER 12dBFS 16 8 16 1...

Page 37: ...le the Mic_HF audio path is suited for hands free function car kit The Earphone applications should be made using the Mic_HF audio path but DISABLING the echo canceller by software AT command If the echo canceller is left active with the Earphone then some echo might be introduced by the echo cancel algorithm UC864 G Mic_MT 1st differential microphone path line coupling AC line type balanced coupl...

Page 38: ...al equivalent signal that means During a call this level varies according to the volume of the talker voice usually the following rough thumb rule for the dynamic range may be used 1 the talker is screaming This is the strongest voice level condition the signal increases by 20dB 2 the talker is whispering This is the lowest voice level condition the voice level decreases by 50dB These changes must...

Page 39: ... distinguish two different types the earphones having the microphone sustained close to the mouth and the ones having the microphone on the earpiece cable The same considerations for the additional voice attenuation due to the distance from the microphone and the noise pick up can be made for the earphone having the microphone on the earpiece cable while the other kind of earphone shall be threate...

Page 40: ...CB balanced and unbalance the path close to the microphone wire connector if possible For the microphone biasing voltage use a dedicated voltage regulator and a capacitor multiply circuit Make sure that the microphone traces in the PCB don t cross or run parallel to noisy traces especially the power line If possible put all around to the microphone lines a ground trace connected to the ground plan...

Page 41: ... must be connected Usually it is indicated by a symbol or a red point If the polarity of the bias is reversed then the microphone will not work properly For this reason be sure to respect the mic biasing polarity 10 4 1 Balanced Microphone Biasing The balanced microphone bias voltage should be obtained from a dedicated voltage regulator in order to eliminate the noise present on the power lines Th...

Page 42: ...changes with the value of R2 and R3 Usually the microphones are characterized with 2kΩ biasing resistance so try to keep the sum of R2 and R3 around 2kΩ Refer to your microphone manufacturer for the mic characteristics 10 4 2 Unbalanced Microphone Biasing The unbalanced microphone biasing voltage should be obtained from a dedicated voltage regulator in order to eliminate the noise present on the p...

Page 43: ...he MIC pad MIC_HF or MIC_MT depending on the audio path chosen or if possible it should be placed close to the shielded cable connector If the ground return path is well designed then it is possible to eliminate the C3 capacitor provided the buffer is close to the mic input NOTE The cable to the microphone should be shielded NOTE The microphone changes with the value of R2 Usually the microphone s...

Page 44: ...circuit shall be placed close to the microphone or close to the microphone wire connector 10 5 1 Buffered Balanced Mic A sample circuit can be This circuit has a gain of 10 times 20 dB and is therefore suited for the Mic_MT input if you have a microphone with a sensitivity close to the suggested one 45 dBVrms Pa If your microphone has a different sensitivity or if the buffer is connected to the Mi...

Page 45: ...e path Mic_MT inputs in normal spoken conditions at acoustic pressure of 4 7dBPa As reported at page 33 the electrical level output from the microphone will be corresponding to When the talker is screaming we will have a signal of 330 mVrms on the Mic_MT inputs due to a 20dB higher Mic Level see TIP 1 with a buffer gain GA GA 20 log AmplifierOutput MicVoltage 20 log 330 10 3 33 10 3 20 log 10 20dB...

Page 46: ...amplifier you will obtain the requested gain because of doubling the microphone signal path in fact by the use of two amplifiers the upper as inverting and the lower as not inverting configuration we obtain an additional 6dB gain 2 times Remember the not inverting amplifier section gain shall not be less than 1 Like for the balanced buffered microphone the amplifier overall gain can be modify chan...

Page 47: ...ken conditions at acoustic pressure of 4 7dBPa As reported at page XX the electrical level output from the microphone will be but we have to consider 20dB loss due to the higher distance from the mouth of the talker 50cm corresponding to In order to have a signal of 1 mVrms at the Mic_HF inputs as suggested at TIP environment consideration the buffer must have a gain or 10 dB Keeping in mind that ...

Page 48: ...uction forbidden without Telit Communications S p A written authorization All Rights Reserved page 48 of 66 C726 1 2π 4000 R719 7 10 10 9 F C727 1 2π 4000 R711 2 65 10 9 F modified in 6 8nF fc1 4181Hz and 2 7nF fc2 3931Hz because of commercial values ...

Page 49: ... or directly a 32 Ω earpiece at 12dBFS Æ the Ear_HF lines EPPA1_2 and EPPA2 are the Fully Differential Power Buffers they can directly drive a 32Ω speaker in differential balanced or single ended unbalanced operation mode FS acronym of Full Scale It is equal to 0dB the maximum Hardware Analog Receive Gain of BaseBand Chip The Ear_MT audio path should be used for handset function while the Ear_HF a...

Page 50: ...acitance 500pF max differential output impedance 1 Ω max 1 02KHz signal bandwidth 150 4000 Hz 3 dB differential output voltage 1060mVrms typ 0dBm0 SW volume level step 2dB number of SW volume steps 10 Ear_HF differential output path line coupling DC line type differential output load resistance 32 Ω max load capacitance 500pF max differential output impedance 1 Ω max 1 02KHz signal bandwidth 150 4...

Page 51: ... to 5 10W required in a car cabin application All the designs shall comply with the following guidelines Where possible use a bridged earphone circuitry to achieve the maximum power output from the device Keep the earphone traces on the PCB and wires as short as possible If your application requires a single ended earpiece and you want a direct connection then leave one of the two output lines ope...

Page 52: ... the power output capability of the UC864 G which is limited and for some particular applications may not be enough For these reasons when the power output of the UC864 G is not enough or if the speaker characteristics are different from the suggested then it is preferable to use an amplifier to increase the power and current output capabilities Again the output from the UC864 G is bridged and bot...

Page 53: ...ld be Some amplifier require a low impedance load at high frequency in order to avoid auto oscillation this can be made with a capacitor 100nF in series with a resistor 15Ω When designing your application remember to provide an adequate bypass capacitor to the amplifier and place it close to the power input pin of the IC keeping the traces as short as possible 11 5 Hands Free Earphone Low Power De...

Page 54: ...as a fixed gain then it can be adjusted to the desired value by reducing the input signal with a resistor divider network The amplifier shall have a mute control to be used while not in conversation This provides two benefits eliminating the background noise when not in conversation and saving power The power to the amplifier should be decoupled as much as possible from the UC864 G power supply by...

Page 55: ...pad at the read time output pads can only be written or queried and set the value of the pad output an alternate function pad is internally controlled by the UC864 G firmware and acts depending on the function implemented Not all GPIO pads support all these three modes GPIO5 supports all three modes and can be input output RFTX monitor output Alternate function GPIO6 supports all three modes and c...

Page 56: ...interface circuits Absolute Maximum Ratings Not Functional UC864 G Parameter Min Max Input level on any digital pin when on 0 3V 3 0V Input voltage on analog pins when on 0 3V 3 0 V For 2 6V CMOS signals Operating Range Interface levels UC864 G Level Min Max Input high level 2 0V 2 9 V Input low level 0 3V 0 6V Output high level 2 2V 2 6V Output low level 0V 0 35V For 2 0V signals Operating Range ...

Page 57: ...4 Using the RFTXMON Output GPIO5 The GPIO5 pin when configured as RFTXMON Output is controlled by the UC864 G module and will rise when the transmitter is active and fall after the transmitter activity is completed For example if a call is started the line will be HIGH during all the conversation and it will be again LOW after hanged up The line rises up 300ms before first TX burst and will become...

Page 58: ... and will drive with appropriate square waves a Buzzer driver This permits to your application to easily implement Buzzer feature with ringing tones or melody played at the call incoming tone playing on SMS incoming or simply playing a tone or melody when needed by your application A sample interface scheme is included below to give you an idea of how to interface a Buzzer to the GPIO7 NOTE To cor...

Page 59: ...e network service availability and Call status In the UC864 G modules the STAT_LED usually needs an external transistor to drive an external LED Therefore the status indicated in the following table is reversed with respect to the pin status LED status Device Status Permanently off Device off Fast blinking Period 1s Ton 0 5s Net search Not registered turning off Slow blinking Period 3s Ton 0 3s Re...

Page 60: ... To this power output a backup capacitor can be added in order to increase the RTC autonomy during power off of the battery NOTE NO Devices must be powered from this pin 12 9 VAUX1 power output A regulated power supply output is provided in order to supply small devices from the module This output is active when the module is ON and goes OFF when the module is shut down The operating range charact...

Page 61: ...ry Min Max Units Voltage range filtered 0 2 6 Volt Range 0 65535 Steps The precision is 16 bits so if we consider that the maximum voltage is 2V the integrated voltage could be calculated with the following formula Integrated output voltage 2 value 65535 DAC_OUT line must be integrated for example with a low band pass filter in order to obtain an analog voltage 13 1 2 Enabling DAC An AT command is...

Page 62: ...UC864 G Hardware User Guide DRAFT 29 10 07 Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 62 of 66 13 1 1 Low Pass Filter Example ...

Page 63: ...ut Voltage range 0 2 6 Volt AD conversion 8 bits Resolution 11 mV The UC864 G module provides 3 Analog to Digital Converters The input lines are ADC_IN1 available on Pin 37 and Pin 19 of PL102 on EVK2 Board CS1203 ADC_IN2 available on Pin 38 and Pin 20 of PL102 on EVK2 Board CS1203 ADC_IN3 available on Pin 39 and Pin 21 of PL102 on EVK2 Board CS1203 13 2 2 Using ADC Converter An AT command is avai...

Page 64: ... S p A written authorization All Rights Reserved page 64 of 66 13 3 Mounting UC864 G on your board The position of the Molex board to board connector and the pin 1 are shown in the following picture NOTE metal tabs present on UC864 G should be connected to GND MOVABLE RF GSM WCDMA MOVABLE RF GPS ...

Page 65: ...debug the mounting of the UC864 G we strongly recommend to foreseen test pads on the host PCB in order to check the connection between the UC864 G itself and the application and to test the performance of the module connecting it with an external computer Depending by the customer application these pads include but are not limited to the following signals TXD RXD ON OFF RESET GND VBATT TX_TRACE RX...

Page 66: ...v vi is si io on n D Da at te e C Ch ha an ng ge es s DRAFT 29 10 07 Regulatory Notices This device is compliant with Parts 15 22 and 24 of the FCC Rules Operation of this device is subject to the following two conditions 1 This device may not cause harmful interference and 2 This device must accept any interference received including interference that may cause undesirable operations ...

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