MC75 Siemens Cellular Engine Version: DocID: 00.190a MC75_V00.
MC75 Hardware Interface Description Strictly confidential / Draft s Document Name: MC75 Hardware Interface Description Version: 00.190a Date: February 15, 2005 DocId: MC75_V00.190a Status: Strictly confidential / Draft General note Product is deemed accepted by Recipient and is provided without interface to Recipient´s products. The Product constitutes pre-release version and code and may be changed substantially before commercial release.
MC75 Hardware Interface Description Strictly confidential / Draft s Contents 0 Document History .........................................................................................................6 1 Introduction ...................................................................................................................8 1.1 Related Documents ...............................................................................................8 1.2 Terms and Abbreviations..........................
MC75 Hardware Interface Description Strictly confidential / Draft s 3.12.2.2 Differential Microphone Input .................................................................51 3.12.2.3 Line Input Configuration with OpAmp ....................................................52 3.12.3 Loudspeaker Circuit ...............................................................................53 3.12.4 Digital Audio Interface DAI.....................................................................54 3.
MC75 Hardware Interface Description Strictly confidential / Draft s Table 16: Signal description ...................................................................................................67 Table 17: Measured electrostatic values................................................................................ 72 Table 18: Summary of reliability test conditions .....................................................................
MC75 Hardware Interface Description Strictly confidential / Draft 0 s Document History Preceding document: "MC75 Hardware Interface Description" Version 00.111 New document: "MC75 Hardware Interface Description" Version 00.190a Chapter What is new 2.3 Updated Figure 2 8.2 Added notes regarding FCC regulations Preceding document: "MC75 Hardware Interface Description" Version 00.111 New document: "MC75 Hardware Interface Description" Version 00.190 Chapter What is new 3.4.
MC75 Hardware Interface Description Strictly confidential / Draft s Preceding document: "MC75 Hardware Interface Description" Version 00.02 New document: "MC75 Hardware Interface Description" Version 00.65 Chapter What is new --- Deleted section about limitations of MC75 Preview Release. Throughout manual Supply voltage range now 3.2V – 4.3V (instead of 3.2V – 4.2V) 2.1 / 5.3 Operating temperature specified. 3.2.2.2 Added section Leakage Current in Power Down Mode. 3.
MC75 Hardware Interface Description Strictly confidential / Draft 1 s Introduction This document describes the hardware of the Siemens MC75 module that connects to the cellular device application and the air interface. It helps you quickly retrieve interface specifications, electrical and mechanical details and information on the requirements to be considered for integrating further components. 1.1 [1] [2] [3] [4] [5] Related Documents MC75 AT Command Set MC75 Release Notes 00.
MC75 Hardware Interface Description Strictly confidential / Draft 1.2 s Terms and Abbreviations Abbreviation Description ADC Analog-to-Digital Converter AGC Automatic Gain Control ANSI American National Standards Institute ARFCN Absolute Radio Frequency Channel Number ARP Antenna Reference Point ASC0 / ASC1 Asynchronous Controller.
MC75 Hardware Interface Description Strictly confidential / Draft s Abbreviation Description ESD Electrostatic Discharge ETS European Telecommunication Standard FCC Federal Communications Commission (U.S.
MC75 Hardware Interface Description Strictly confidential / Draft Abbreviation Description PSK Phase Shift Keying PSU Power Supply Unit R&TTE Radio and Telecommunication Terminal Equipment RAM Random Access Memory RF Radio Frequency RMS Root Mean Square (value) ROM Read-only Memory RTC Real Time Clock RTS Request to Send Rx Receive Direction SAR Specific Absorption Rate SD Secure Digital SELV Safety Extra Low Voltage SIM Subscriber Identification Module SMS Short Message Serv
MC75 Hardware Interface Description Strictly confidential / Draft 1.3 s Type Approval MC75 is designed to comply with the directives and standards listed below. Please note that the product is still in a pre-release state and, therefore, type approval and testing procedures have not yet been completed.
MC75 Hardware Interface Description Strictly confidential / Draft s Requirements of quality IEC 60068 Environmental testing DIN EN 60529 IP codes Compliance with international rules and regulations Manufacturers of mobile or fixed devices incorporating MC75 modules are advised to have their completed product tested and approved for compliance with all applicable national and international regulations.
MC75 Hardware Interface Description Strictly confidential / Draft 1.4 s Safety Precautions The following safety precautions must be observed during all phases of the operation, usage, service or repair of any cellular terminal or mobile incorporating MC75. Manufacturers of the cellular terminal are advised to convey the following safety information to users and operating personnel and to incorporate these guidelines into all manuals supplied with the product.
MC75 Hardware Interface Description Strictly confidential / Draft SOS s IMPORTANT! Cellular terminals or mobiles operate using radio signals and cellular networks. Because of this, connection cannot be guaranteed at all times under all conditions. Therefore, you should never rely solely upon any wireless device for essential communications, for example emergency calls.
MC75 Hardware Interface Description Strictly confidential / Draft 2 Product Concept 2.
MC75 Hardware Interface Description Strictly confidential / Draft Feature s Implementation CSD • V.110, RLP, non-transparent • 2.4, 4.8, 9.6, 14.4 kbps • USSD PPP-stack for GPRS data transfer SMS • • • • • Fax Group 3; Class 1 Audio Speech codecs: • Half rate HR (ETS 06.20) • Full rate FR (ETS 06.10) • Enhanced full rate EFR (ETS 06.50/06.60/06.
MC75 Hardware Interface Description Strictly confidential / Draft Feature s Implementation ASC1 • 4-wire, unbalanced asynchronous interface • 1.2 kbps to 460 kbps • Autobauding TBD • Supports RTS1/CTS1 hardware handshake and software XON/XOFF flow control USB Supports a USB 2.0 Full Speed (12 Mbit/s) slave interface. I2 C I2C bus for transmission rates up to 400 kbps SD card interface Interface for SD memory card or multimedia card Audio • • SIM interface Supported SIM cards: 3V, 1.
s MC75 Hardware Interface Description Strictly confidential / Draft 2.2 MC75 System Overview MC75 Antenna Interface SD interface Application Interface I2C SIM SIM card USB USB Host I2C Slave Serial 1 Serial 2 (Modem) UART Digital Audio Analog Audio Charge SD memory card Power Supply Audio Codec Headphones or Headset Charging circuit Charger User Application Figure 1: MC75 system overview MC75_V00.190a Page 19 of 91 15.02.
s MC75 Hardware Interface Description Strictly confidential / Draft 2.
MC75 Hardware Interface Description Strictly confidential / Draft 3 s Application Interface MC75 is equipped with an 80-pin board-to-board connector that connects to the external application. The host interface incorporates several sub-interfaces described in the following chapters: • • • • • • • • • • • Power supply - see Section 3.1 Charger interface – Section 3.4 SIM interface - see Section 3.6 Serial interface ASC0 - see Section 3.7 Serial interface ASC1 - see Section 3.
s MC75 Hardware Interface Description Strictly confidential / Draft 3.1 Power Supply MC75 needs to be connected to a power supply at the B2B connector (5 pins each BATT+ and GND). The power supply of MC75 has to be a single voltage source at BATT+. It must be able to provide the peak current during the uplink transmission. All the key functions for supplying power to the device are handled by the power management section of the analog controller.
s MC75 Hardware Interface Description Strictly confidential / Draft 3.1.2 Measuring the Supply Voltage VBATT+ The reference points for measuring the supply voltage VBATT+ on the module are BATT+ and GND, both accessible at a capacitor located close to the board-to-board connector of the module. Reference point BATT+ Reference point GND Figure 4: Position of the reference points BATT+ and GND 3.1.
MC75 Hardware Interface Description Strictly confidential / Draft 3.2 s Power Up / Power Down Scenarios In general, be sure not to turn on MC75 while it is beyond the safety limits of voltage and temperature stated in Chapter 5. MC75 would immediately switch off after having started and detected these inappropriate conditions. In extreme cases this can cause permanent damage to the module. 3.2.
s MC75 Hardware Interface Description Strictly confidential / Draft If configured to a fix baud rate (AT+IPR≠0), the module will send the URC “^SYSSTART” to notify that it is ready to operate. If autobauding is enabled (AT+IPR=0) there will be no notification. BATT+ tmin = 300ms IGT HiZ PWR_IND 120ms EMERG_RST VEXT TXD0/TXD1/RTS0/RST1/DTR0 (driven by the application) CTS0/CTS1/DSR0/DCD0 Undefined Serial interfaces ASC0 and ASC1 Active ca.
s MC75 Hardware Interface Description Strictly confidential / Draft BATT+ tmin = 300ms HiZ IGT PWR_IND 120ms EMERG_RST VEXT TXD0/TXD1/RTS0/RST1/DTR0 (driven by the application) CTS0/CTS1/DSR0/DCD0 Undefined Serial interfaces ASC0 and ASC1 Active ca. 500 ms Figure 6: Power-on with IGT held low before switching on operating voltage at BATT+ 3.2.1.2 Turn on MC75 Using the VCHARGE Signal As detailed in Section 3.4.5, the charging adapter can be connected regardless of the module’s operating mode.
MC75 Hardware Interface Description Strictly confidential / Draft s 3.2.1.3 Reset MC75 via AT+CFUN Command To reset and restart the MC75 module use the command AT+CFUN. You can enter AT+CFUN=,1 or AT+CFUN=x,1, where x may be in the range from 0 to 9. See [1] for details. If configured to a fix baud rate (AT+IPR≠0), the module will send the URC “^SYSSTART” to notify that it is ready to operate. If autobauding is enabled (AT+IPR=0) there will be no notification.
MC75 Hardware Interface Description Strictly confidential / Draft 3.2.2 s Turn off MC75 MC75 can be turned off as follows: • Normal shutdown: Software controlled by AT^SMSO command • Automatic shutdown: Takes effect if board or battery temperature is out of range or if undervoltage or overvoltage conditions occur. 3.2.2.1 Turn off MC75 Using AT Command The best and safest approach to powering down MC75 is to issue the AT^SMSO command.
s MC75 Hardware Interface Description Strictly confidential / Draft PWR_IND See note 1 VEXT CTS0/CTS1/DSR0/DTR0 TXD0/TXD1/RTS0/RTS1/DTR0 (driven by the application) Active Undefined Serial interfaces ASC0 and ASC1 Figure 7: Signal states during turn-off procedure Note 1: Depending on capacitance load from host application 3.2.2.
MC75 Hardware Interface Description Strictly confidential / Draft 3.2.3 s Automatic Shutdown Automatic shutdown takes effect if • the MC75 board is exceeding the critical limits of overtemperature or undertemperature • the battery is exceeding the critical limits of overtemperature or undertemperature • undervoltage or overvoltage is detected The automatic shutdown procedure is equivalent to the Power-down initiated with the AT^SMSO command, i.e.
MC75 Hardware Interface Description Strictly confidential / Draft s Table 1: Temperature dependent behavior Sending temperature alert (15 s after MC75 start-up, otherwise only if URC presentation enabled) ^SCTM_A: 1 Caution: Tamb of battery close to overtemperature limit. ^SCTM_B: 1 Caution: Tamb of board close to overtemperature limit. ^SCTM_A: -1 Caution: Tamb of battery close to undertemperature limit. ^SCTM_B: -1 Caution: Tamb of board close to undertemperature limit.
MC75 Hardware Interface Description Strictly confidential / Draft 3.2.3.4 s Undervoltage Shutdown if no Battery NTC is Present The undervoltage protection is also effective in applications, where no NTC connects to the BATT_TEMP terminal. Thus, you can take advantage of this feature even though the application handles the charging process or MC75 is fed by a fixed supply voltage. All you need to do is executing the write command AT^SBC= which automatically enables the presentation of URCs.
MC75 Hardware Interface Description Strictly confidential / Draft 3.3 s Automatic EGPRS/GPRS Multislot Class Change Temperature control is also effective for operation in EGPRS Multislot Class 10 and GPRS Multislot Class 12.
MC75 Hardware Interface Description Strictly confidential / Draft 3.4 s Charging Control MC75 integrates a charging management for rechargeable Lithium Ion and Lithium Polymer batteries. You can skip this chapter if charging is not your concern, or if you are not using the implemented charging algorithm. MC75 has no on-board charging circuit. To benefit from the implemented charging management you are required to install a charging circuit within your application according to the Figure 39.
s MC75 Hardware Interface Description Strictly confidential / Draft Figure 8 shows the circuit diagram of a typical battery pack design that includes the protection elements described above. to BATT+ to BATT_TEMP to GND ϑ NTC Protection Circuit + Figure 8: Battery pack circuit diagram Battery cell Polyfuse Table 2: Specifications of battery packs suitable for use with MC75 Battery type Rechargeable Lithium Ion or Lithium Polymer battery Nominal voltage 3.6V / 3.
MC75 Hardware Interface Description Strictly confidential / Draft 3.4.3 s Charger Requirements For using the implemented charging algorithm and the reference charging circuit recommended in [4] and in Figure 39, the charger has to meet the following requirements: Output voltage: 5.2Volts ±0.2V (stabilized voltage) Output current: 500mA Chargers with a higher output current are acceptable, but please consider that only 500mA will be applied when a 0.
s MC75 Hardware Interface Description Strictly confidential / Draft 3.4.5 Operating Modes during Charging Of course, the battery can be charged regardless of the engine's operating mode. When the GSM module is in Normal mode (SLEEP, IDLE, TALK, GPRS IDLE or GPRS DATA mode), it remains operational while charging is in progress (provided that sufficient voltage is applied). The charging process during the Normal mode is referred to as Charge mode.
s MC75 Hardware Interface Description Strictly confidential / Draft 3.5 RTC Backup The internal Real Time Clock of MC75 is supplied from a separate voltage regulator in the analog controller which is also active when MC75 is in POWER DOWN status. An alarm function is provided that allows to wake up MC75 without logging on to the GSM network. In addition, you can use the VDDLP pin on the board-to-board connector to backup the RTC from an external capacitor or a battery (rechargeable or non-chargeable).
MC75 Hardware Interface Description Strictly confidential / Draft 3.6 s SIM Interface The baseband processor has an integrated SIM interface compatible with the ISO 7816 IC Card standard. This is wired to the host interface (board-to-board connector) in order to be connected to an external SIM card holder. Six pins on the board-to-board connector are reserved for the SIM interface. The SIM interface supports 3V and 1.8V SIM cards.
s MC75 Hardware Interface Description Strictly confidential / Draft 3.7 Serial Interface ASC0 MC75 offers an 8-wire unbalanced, asynchronous modem interface ASC0 conforming to ITU-T V.24 protocol DCE signalling. The electrical characteristics do not comply with ITU-T V.28. The significant levels are 0V (for low data bit or active state) and 2.9V (for high data bit or inactive state). For electrical characteristics please refer to Table 16. MC75 is designed for use as a DCE.
s MC75 Hardware Interface Description Strictly confidential / Draft Table 6: DCE-DTE wiring of ASC0 V.24 circuit DCE DTE Pin function Signal direction Pin function Signal direction 103 TXD0 Input TXD Output 104 RXD0 Output RXD Input 105 RTS0 Input RTS Output 106 CTS0 Output CTS Input 108/2 DTR0 Input DTR Output 107 DSR0 Output DSR Input 109 DCD0 Output DCD Input 125 RING0 Output /RING Input MC75_V00.190a Page 41 of 91 15.02.
s MC75 Hardware Interface Description Strictly confidential / Draft 3.8 Serial Interface ASC1 MC75 offers a 4-wire unbalanced, asynchronous modem interface ASC1 conforming to ITUT V.24 protocol DCE signalling. The electrical characteristics do not comply with ITU-T V.28. The significant levels are 0V (for low data bit or active state) and 2.9V (for high data bit or inactive state). For electrical characteristics please refer to Table 16. MC75 is designed for use as a DCE.
s MC75 Hardware Interface Description Strictly confidential / Draft 3.9 USB Interface MC75 supports a USB 2.0 Full Speed (12 Mbit/s) device interface. It is primarily intended for use as command and data interface and for downloading firmware. The USB I/O-pins are capable of driving the signal at min 3.0V. They are 5V I/O compliant. To properly connect the module’s USB interface to the host a USB 2.0 compatible connector is required.
MC75 Hardware Interface Description Strictly confidential / Draft 3.9.1 s Installing the USB Modem Driver This section assumes you are familiar with installing and configuring a modem under Windows 2000 and Windows XP. As both operating systems use multiple methods to access modem settings this section provides only a brief summary of the most important steps. Take care that the “usbmodem.inf” file delivered with MC75 is at hand.
MC75 Hardware Interface Description Strictly confidential / Draft s You can find the “Siemens AG WM USB Modem” listed under Control Panel | Phone and Modem Options | Modems.
s MC75 Hardware Interface Description Strictly confidential / Draft 3.10 I2C Interface I2C is a serial, 8-bit oriented data transfer bus for bit rates up to 400 kbps in Fast mode. It consists of two lines, the serial data line I2CDAT and the serial clock line I2CCLK. The MC75 module acts as a single master device, e.g. the clock I2CCLK is driven by module. I2CDAT is a bi-directional line.
s MC75 Hardware Interface Description Strictly confidential / Draft 3.11 SD Memory Card Interface The SD card interface is compliant with the “SD Memory Card Specifications / Part 1 Physical Layer Specification, Version 1.01”. The interface supports the following features: • Data rates up to 3250 kByte/s. • The read/write data rate depends on the clock rate.
s MC75 Hardware Interface Description Strictly confidential / Draft SD_CLK VEXT SD_CMD SD_D3 SD_D2 47k 8 7 6 5 4 3 2 1 9 DAT1 DAT0 GND CLK VDD GND CMD lock Baseband controller SD_D1 SD_D0 Write protect slide Card detect unlock SD_DET 80 pole board-to-board connector SD_WP 1) 50k CD/DAT3 DAT2 SD card Analog controller SD card holder 1) Internal switch is closed after power-up and open during regular data transfer. Used for card detection.
s MC75 Hardware Interface Description Strictly confidential / Draft 3.12 Audio Interfaces MC75 comprises three audio interfaces available on the board-to-board connector: • Two analog audio interfaces, both with balanced or single-ended inputs/outputs. • Serial digital audio interface (DAI) designed for PCM (Pulse Code Modulation). This means you can connect up to three different audio devices, although only one interface can be operated at a time.
s MC75 Hardware Interface Description Strictly confidential / Draft 3.12.1 Speech Processing The speech samples from the ADC or DAI are handled by the DSP of the baseband controller to calculate e.g. amplifications, sidetone, echo cancellation or noise suppression depending on the configuration of the active audio mode. These processed samples are passed to the speech encoder.
MC75 Hardware Interface Description Strictly confidential / Draft s The VMIC voltage should be filtered if gains larger than 20dB are used. The filter can be attached as a simple first order RC-network (RVMIC and CF). This circuit is well suited if the distance between microphone and module is kept short. Due to good grounding the microphone can be easily ESD protected as its housing usually connects to the negative terminal. 3.12.2.
MC75 Hardware Interface Description Strictly confidential / Draft 3.12.2.3 s Line Input Configuration with OpAmp Figure 21 shows an example of how to connect an opamp into the microphone circuit. RA = typ. 47k RVMIC = 470Ohm VMIC R CK RVMIC Ck = typ. 100nF CF = typ. 22µF MICPx ~ VMIC = typ. 2.5V R CK GSM module MICNx CF Vbias = typ. ½ VMIC = 1.25V VBias AGND Figure 21: Line input configuration with OpAmp The AC source (e.g.
s MC75 Hardware Interface Description Strictly confidential / Draft 3.12.3 Loudspeaker Circuit The GSM module comprises two analog speaker outputs: EP1 and EP2. Output EP1 is able to drive a load of 8Ohms while the output EP2 can drive a load of 32Ohms. Each interface can be connected in differential and in single ended configuration. See examples in Figure 22 and Figure 23. Loudspeaker impedance EPP1/EPN1 ZL = typ. 8Ohm EPP2/EPN2 ZL = typ.
s MC75 Hardware Interface Description Strictly confidential / Draft 3.12.4 Digital Audio Interface DAI The DAI can be used to connect audio devices capable of PCM (Pulse Code Modulation), for example a codec.
s MC75 Hardware Interface Description Strictly confidential / Draft The timing of a PCM short frame is shown in Figure 25. In PCM mode, 16-bit data are transferred in both directions at the same time. The duration of a frame sync pulse is one BITCLK period, starting at the rising edge of BITCLK. TXDAI data is shifted out at the next rising edge of BITCLK. The most significant bit is transferred first. Data transmitted from RXDAI of the internal application is sampled at the falling edge of BITCLK.
MC75 Hardware Interface Description Strictly confidential / Draft 3.13 Control Signals 3.13.1 Synchronization Signal s The synchronization signal serves to indicate growing power consumption during the transmit burst. The signal is generated by the SYNC pin (pin number 32).
MC75 Hardware Interface Description Strictly confidential / Draft 3.13.2 s Using the SYNC Pin to Control a Status LED As an alternative to generating the synchronization signal, the SYNC pin can be configured to drive a status LED that indicates different operating modes of the MC75 module. To take advantage of this function the LED mode must be activated with the AT^SSYNC command and the LED must be connected to the host application.
s MC75 Hardware Interface Description Strictly confidential / Draft 4 Antenna Interface The RF interface has an impedance of 50Ω. MC75 is capable of sustaining a total mismatch at the antenna connector or pad without any damage, even when transmitting at maximum RF power. The external antenna must be matched properly to achieve best performance regarding radiated power, DC-power consumption, modulation accuracy and harmonic suppression.
s MC75 Hardware Interface Description Strictly confidential / Draft Antenna connected to Hirose connector: Module PAD U.FL Antenna connected to pad: Antenna or measurement equipment Module PAD 50Ohm 50Ohm 50Ohm U.FL Z Z Antenna or measurement equipment 50Ohm Figure 28: Never use antenna connector and antenna pad at the same time No matter which option you choose, ensure that the antenna pad does not come into contact with the holding device or any other components of the host application.
MC75 Hardware Interface Description Strictly confidential / Draft 4.2 s Antenna Pad The antenna can be soldered to the pad, or attached via contact springs. For proper grounding connect the antenna to the ground plane on the bottom of MC75 which must be connected to the ground plane of the application. When you decide to use the antenna pad take into account that the pad has not been intended as antenna reference point (ARP) for the Siemens MC75 type approval.
s MC75 Hardware Interface Description Strictly confidential / Draft 4.3 Antenna Connector MC75 uses an ultra-miniature SMT antenna connector supplied from Hirose Ltd. The product name is: U.FL-R-SMT The position of the antenna connector on the MC75 board can be seen in Figure 30. Figure 30: Mechanical dimensions of U.FL-R-SMT connector Table 11: Product specifications of U.
s MC75 Hardware Interface Description Strictly confidential / Draft Table 12: Material and finish of U.FL-R-SMT connector and recommended plugs Part Material Finish Shell Phosphor bronze Silver plating Male center contact Brass Gold plating Female center contact Phosphor bronze Gold plating Insulator Plug: Receptacle: PBT LCP Black Beige Mating plugs and cables can be chosen from the Hirose U.FL Series. Examples are shown below and listed in Table 13.
MC75 Hardware Interface Description Strictly confidential / Draft s In addition to the connectors illustrated above, the U.FL-LP-(V)-040(01) version is offered as an extremely space saving solution. This plug is intended for use with extra fine cable (up to ∅ 0.81 mm) and minimizes the mating height to 2 mm. See Figure 33 which shows the Hirose datasheet. Figure 33: Specifications of U.FL-LP-(V)-040(01) plug MC75_V00.190a Page 63 of 91 15.02.
s MC75 Hardware Interface Description Strictly confidential / Draft Table 13: Ordering information for Hirose U.FL Series Item Part number HRS number Connector on MC75 U.FL-R-SMT CL331-0471-0-10 Right-angle plug shell for ∅ 0.81 mm cable U.FL-LP-040 CL331-0451-2 Right-angle plug for ∅ 0.81 mm cable U.FL-LP(V)-040 (01) CL331-053-8-01 Right-angle plug for ∅ 1.13 mm cable U.FL-LP-068 CL331-0452-5 Right-angle plug for ∅ 1.32 mm cable U.FL-LP-066 CL331-0452-5 Extraction jig E.
s MC75 Hardware Interface Description Strictly confidential / Draft 5 Electrical, Reliability and Radio Characteristics 5.1 Absolute Maximum Ratings The absolute maximum ratings stated in Table 14 are stress ratings. Stresses beyond any of these limits will cause permanent damage to MC75. Table 14: Absolute maximum ratings Parameter Min Max Unit Supply voltage BATT+ -0.3 5.5 V Voltage at digital pins -0.3 3.05 V Voltage at analog pins -0.3 3.
s MC75 Hardware Interface Description Strictly confidential / Draft 5.3 Pin Assignment and Signal Description The Molex board-to-board connector on MC75 is an 80-pin double-row receptacle. The names and the positions of the pins can be seen from Figure 1 which shows the top view of MC75.
MC75 Hardware Interface Description Strictly confidential / Draft s Please note that the reference voltages listed in Table 16 are the values measured directly on the MC75 module. They do not apply to the accessories connected. Table 16: Signal description Function Signal name Power supply BATT+ IO I Signal form and level Comment VImax = 4.3V VItyp = 3.8V VImin = 3.
MC75 Hardware Interface Description Strictly confidential / Draft s Function Signal name IO Signal form and level Comment Power indicator PWR_IND O VIHmax = 10V VOLmax = 0.4V at Imax = 2mA PWR_IND (Power Indicator) notifies the module’s on/off state. PWR_IND is an open collector that needs to be connected to an external pullup resistor. Low state of the open collector indicates that the module is on. Vice versa, high level notifies the Powerdown mode.
MC75 Hardware Interface Description Strictly confidential / Draft Function Signal name SIM interface CCIN specified for use with 3V SIM card IO I Signal form and level Comment RI ≈ 100kΩ VILmax = 0.6V at I = -25µA VIHmin = 2.1V at I = -10µA, VOmax= 3.05V CCIN = Low, SIM card holder closed Maximum cable length or copper track 100mm to SIM card holder. CCRST O RO ≈ 47Ω VOLmax = 0.25V at I = +1mA VOHmin = 2.5V at I = -0.5mA VOHmax = 2.95V CCIO I/O RI ≈ 4.7kΩ VILmax = 0.75V VILmin = -0.
MC75 Hardware Interface Description Strictly confidential / Draft s Function Signal name IO Signal form and level Comment ASC1 Serial interface RXD1 TXD1 CTS1 RTS1 O I O I VOLmax = 0.2V at I = 2mA VOHmin = 2.55V at I = -0.5mA VOHmax = 3.05V Serial interface for AT commands or data stream. I2CCLK O VOLmax = 0.2V at I = 2mA VOHmin = 2.55V at I = -0.5mA VOHmax = 3.05V I2CDAT I/O VOLmax = 0.2V at I = 2mA VILmax = 0.8V VIHmin = 2.0V I2C interface VILmax = 0.8V VIHmin = 2.
