Motorola Astro Xts5000 Detailed 6881094c31 E Manual

							November 16, 20066881094C31-E
3-12Theory of Operation: Transceiver Board
3.1.3.9.1  Power and Control
Since U104 is powered from switched B+, it makes its own regulated 4.5 Vdc to power the internal 
logic. The supply input is V5EXT at pin 17, and the output is V45 at pin 16. RX at pin 23 is the control 
signal to the antenna switch control circuit.
3.1.3.9.2  Voltage Multiplier
The PCIC contains an internal voltage multiplier. This multiplier produces signal V10 (pin 14), a 10-V 
supply for the PCIC D/A converters (DACs). This enables the DACs outputs to reach 8 V. The FREF 
signal is a 2.1 MHz clock used to switch the multiplier. The voltage multiplier is not used in either the 
VHF, UHF Range 1, UHF Range 2, or 700–800 MHz radio.
3.1.3.9.3  Automatic Level Control (ALC)
In TX mode, the PCIC disables the receiver, turns on the transmitter, and controls the TX power 
level. The automatic level control (ALC) circuit operates as follows:
9 F168 Reference clock input, 2.1 MHz
10, 13 QX, CQX External capacitor for voltage multiplier
11, 12 Q, CQ External capacitor for voltage multiplier
14 V10 Voltage multiplier output
15 VG Internal band-gap reference voltage
16 V45 Regulated 4.5 Vdc output
17 V5EXT Power supply input for internal voltage regulator
18 VAR2 Buffered D/A output
19 VLIM Test point for internal D/A No.2 voltage
20 VAR1 Buffered D/A output
21 RS Asynchronous reset input
22 NA Spare pin
23 RX RX/TX mode control-bit output
24 VAR3 Buffered D/A output
25 GND2 Ground
26 CLK SPI clock input
27 BPOS Power supply input
28 DATA SPI data input/output
29 CEX SPI chip select input
30 TEMP Temperature sensor input
31 RSET External resistor; used to set the temperature cutback rate
32 ANO Switched BPOS output 
Table 3-3.  Power Control IC (U104) Pin Descriptions (Continued)
PinNameDescription 
						

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Theory of Operation: Transceiver Board3-13
The power level is set by programming an internal DAC to a calibrated reference voltage. D/A 
settings for the power set points were determined during radio tuning and stored in EEPROM. An 
internal op-amp compares the D/A reference voltage to the detector voltage at pin 1(RFIN) (TP101) 
and produces an error signal output. This signal is buffered by another op-amp, configured as a low-
pass filter, or integrator, to produce the INT output at pin 4 (TP104). This signal drives the base of 
voltage follower Q108.
Transistor Q108 supplies current to drive the gain control pins of amplifiers U102 and Q107. 
Resistors R105 and R106 determine the voltage ratio between U102 pin 2 (VCNTRL) and the Q107 
gate. Transient response during key-up and key-down is controlled by the power amplifier rise and 
fall times. External capacitors at pins CI, CJ, and CL, along with internal programmable resistors, 
determine the ALC time constants.
3.1.3.9.4  Temperature Cut Back
The PCIC contains a temperature cut-back circuit to protect the power amplifier (PA) from thermal 
damage that might result from incorrect assembly of the radio. External sensor U103 is a linear 
temperature-to-voltage transducer, placed near the hottest spot in the radio: power module Q107. 
The output is a DC voltage at pin 2 (VOUT) proportional to the temperature at pin 3 (GND). VOUT is 
750 mV at 25°C and increases by 10 mV/°C. The PCIC temperature cut-back threshold is 
programmed to correspond to 85 or 90°C. Above this threshold, the ALC gradually cuts back the 
transmitter until it is fully turned off at 125°C. The slope of cut-back versus temperature is set by 
external resistor R111. Diode D104 clamps TEMP to a voltage not much less than VG (pin 15), about 
1.3 V, to improve the transient response of the cut-back circuit.
3.1.3.9.5  D/A Outputs
In RX mode, the PCIC shuts down the transmitter, turns on the receiver, and tunes the RX front-end 
pre-selector filters.
VHF: Signal VAR2 supplies the voltage used to tune both front-end preselector filters. The voltage 
range varies from 1.2 V to 2.4 V across the VHF band.
UHF Range 1: Signal VAR2 tunes both receiver preselector filters. Control voltage is in the 1 to 4 V 
range.
UHF Range 2: Signal VAR2 supplies the voltage used to tune both front-end preselector filters. The 
voltage
range varies from 1.2 V to 3.6 V.
700–800 MHz: Signals VAR1 and VAR2 are D/A outputs to the RX front-end preselector filters. 
Output voltage is in the range of about 1 to 4 V over the frequency band. In TX mode, VAR1 and 
VAR2 disconnect from the D/A and go to 0 Vdc, thus tuning the RX front-end filters out of band.
3.1.4 Frequency Generation Unit (FGU)
The frequency-generation function is performed by several ICs; multiple, discrete, voltage-controlled 
oscillators (VCOs); and associated circuitry. The reference oscillator provides a frequency standard 
to the fractional-N frequency synthesizer (FracN) IC, which controls the VCOs and VCO buffer IC 
(VCOBIC). The VCOBIC amplifies the VCO signal to the correct level for the next stage.
VHF: Two VCOs are employed—one to generate the first LO and the other to generate the transmit-
injection signals.
UHF Range 1: Four VCOs are employed: two transmit and two receive.
UHF Range 2: Three VCOs are employed: one transmit and two receive. 
						

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3-14Theory of Operation: Transceiver Board
700–800 MHz: Three VCOs generate the first LO and transmit-injection signals.
NOTE:Refer to Table 8-1, “List of Transceiver Schematics and Board Overlays,” on page 8-1 for a 
listing of FGU-related schematics that will aid in the following discussion.
3.1.4.1  Reference Oscillator Y200
The radios frequency stability and accuracy derive from the Voltage-Controlled Temperature-
Compensated Crystal Oscillator (VCTCXO), Y200. This 16.8 MHz oscillator is controlled by the 
voltage from the WARP pin of the FracN (fractional-N frequency synthesizer) IC, U202, that can be 
programmed through a serial peripheral interface (SPI). The oscillator output at pin 3 is coupled 
through capacitor C234 to the FracN synthesizer reference oscillator input and through C236 (C237 
for VHF and UHF Range 2) to the non-invertive input of the op-amp, U201.
Op-amp U201 buffers the 16.8 MHz output to the VOCON board. Components L205 and C214 
(C213, L205, and C214 for VHF) form a low-pass filter to reduce harmonics of the 16.8 MHz.
The Digital-to-Analog Converter (DAC) IC, U203, and Switched Capacitors Filter (SCF) IC, FL200, 
form the interface between radios DSP and the analog modulation input of the FracN IC.
3.1.4.2  Fractional-N Frequency Synthesizer (FracN) IC U202
The FracN IC, U202, is a mixed-mode, Motorola-proprietary, CMOS, fractional-N frequency 
synthesizer with built-in dual-port modulation. The XTS 5000 radio uses a low-voltage version of the 
device, sometimes called LVFracN, for compatibility with the 3 V logic used throughout the radio.
The FracN IC incorporates frequency division and comparison circuitry to keep the VCO signals 
stable. The FracN IC is controlled by the MCU through a serial bus. All of the synthesizer circuitry is 
enclosed in rigid metal cans on the transceiver board to reduce interference effects.
Separate power supply inputs are used for the various functional blocks on the IC. Inductors L203 
and L204 provide isolation between supply pins 20 (AVDD) and 36 (DVDD) connected to Vdd3. Host 
control is through a three-wire, smart SPI interface (pins 7, 8, and 9) with a bi-directional data pin. 
FracN functions include frequency synthesis, reference clock generation, modulation control, voltage 
multiplication and filtering, and auxiliary logic outputs.
3.1.4.2.1  Synthesizer
Frequency synthesis functions include a dual-modulus prescaler, a phase detector, a programmable 
loop divider and its control logic, a charge pump, and a lock detector output. Fractional-N synthesizer 
IC principles of operation are covered in detail in the manufacturers literature. No similar discussion 
will be attempted here.
3.1.4.2.2  Clocks
U202, pin 23 (XTAL1), is the 16.8 MHz reference oscillator input from the VCTCXO (Y200).
3.1.4.2.3  Modulation
To support many voice, data, and signaling protocols, XTS 5000 radios must modulate the 
transmitter carrier frequency over a wide audio frequency range, from less than 10 Hz up to more 
than 6 kHz. The FracN supports audio frequencies down to zero Hz by using dual-port modulation. 
The audio signal at pin 10 (MODIN) is internally divided into high- and low-frequency components, 
which modify both the synthesizer dividers and the external VCOs through signal MODOUT (pin 41). 
The IC is adjusted to achieve flat modulation frequency response during transmitter modulation 
balance calibration using a built-in modulation attenuator. 
						

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Theory of Operation: Transceiver Board3-15
3.1.4.2.4  Voltage Multiplier and Superfilter
Pins 12 (VMULT3) and 11 (VMULT4) together with diode arrays D201 and D202 and their associated 
capacitors form the voltage multiplier. The voltage multiplier generates 11.5 Vdc to supply the phase 
detector and charge-pump output stage at pin 47 (VCP).
The superfilter is an active filter that provides a low-noise supply for the VCOs and VCOBIC. The 
input is regulated 5 Vdc from Vdd5 at pin 30 (SFIN). The output is superfiltered voltage FSF at pin 28 
(SFOUT).
The output from pin 15 (VMULT1) is used as a clock for the SCF IC, FL200.
3.1.4.3  Loop Filter
The components connected to pins 43 (IOUT) and 45 (IADAPT) form a 3rd-order, RC low-pass filter. 
Current from the charge-pump output, IOUT, is transformed to voltage VCTRL, which modulates the 
VCOs. Extra current is supplied by IADAPT for rapid phase-lock acquisition during frequency 
changes. The lock detector output pin 4 (LOCK) goes to a logic “1” to indicate when the phased-lock 
loop is in lock.
3.1.4.4  VCO Buffer IC (VCOBIC)
The VCOBIC (U302 for VHF radios or U300 for UHF Range 1 and 700–800 MHz radios) is an 
analog IC containing two NPN transistors for use as oscillators, an active-bias circuit, transmitter and 
receiver buffer amplifiers, and switching circuitry. The VCOBIC has three RF outputs:
• TX_OUT (pin 10)—the modulated transmitter carrier
• RX_OUT (pin 8)—the receiver first LO
• PRESC_OUT (pin 12)—connected to FracN pin 32 (PREIN) through a matching circuit
Transmit/receive control is a single 5.0 Vdc logic input, TRB_IN (pin 19). When TRB_IN is low, the 
receiver buffer is active and the transmitter circuits are disabled. The converse is also true.
VHF: The VCOs in VHF radios use the VCOBIC internal transistors and implement the active bias 
via resistors R304 and R305. Bias to TX_OUT is supplied through resistor R313. Components L309 
and C316 form a matching circuit for the TX_OUT impedance. C319 acts as a DC block, and 
resistors R314, R315, and R316 attenuate an output signal to an optimum level for the PA.
L312 and C320 form a low-pass bias supply filter for the RX_OUT. L310 and C317 are the RX_OUT 
impedance-matching circuit. C322 is a DC block, and resistors R317 and R318 attenuate an output 
signal to an optimum level for the mixer IC.
An NPN/PNP-packaged transistor, Q301, together with the supporting components R308, R309, and 
R310, form the 3.3 Vdc-to-5 Vdc logic-level shifter between the AUX3 pin of the FracN IC, U202, and 
VCOBIC, U302.
UHF Range 1: For these radios, four VCOs are used: two transmit and two receive. Control-logic 
translation is done by level shifter Q310 and Q311, and wired-OR D320.
UHF Range 2: Two VCOs are used for receive and one for Transmit.  The fractional N synthesizer 
selects the appropriate VCO by toggling auxilary lines 2,3, or 4.  The selection of the TX VCO with 
auxilary line 4 also sets TRB_IN high.
700–800 MHz: These radios use three external, discrete, varactor-tuned, Colpitts VCOs based on 
transistors Q301, Q303, and Q308. Bias current to the VCOs is switched on and off by the 
transistors Q302, Q306, and Q309, which are controlled by FracN outputs AUX1, AUX2, and AUX4. 
Transistor Q304 is an additional transmit buffer amplifier reducing frequency pulling on the transmit 
VCO. An additional buffer is switched on and off by the transistor Q305. Bias to TX_OUT is supplied 
through resistor R307. Components L307 and C208 form a low-pass bias supply filter. The RX_OUT 
impedance is matched by a one-component match, coil L310. 
						

							November 16, 20066881094C31-E
3-16Theory of Operation: VOCON Board
Transistors Q307 and Q310 form a 3.3 Vdc-to-5 Vdc logic-level shifter for the signal from the FracN 
AUX3 pin to the VCOBIC.
3.2 VOCON Board
This section provides a detailed circuit description of the ASTRO XTS 5000 VOCON board.
The VOCON board (Figure 3-7 and Figure 3-8) is divided into the following sections:
• Controller and Memory
• Audio and Power
• Interface Support
3.2.1 Interconnections
The VOCON board interconnection diagram (see Figure 3-7 and Figure 3-8) contains three 
functional blocks and five connector symbols.
Figure 3-7.  VOCON Board Interconnections
SRAM
1MByte INTERFACE SUPPORT
ESD Protection and
Side Connector
CircuitryASIC
Clocks and Side
Connector Support
VOCON
Board
CONTROLLER AND  MEMORY
FLASH
8MBytes
Dual-Core
Processor
MCU and DSPKeypad
22 pins
Display
22 pins
Encryption
40 pins AUDIO AND  POWER
Audio
EEPOT
Pre-amp and
Power Amp
GCAP II
and Discrete
Voltage Regulators RF
26 pins
Universal
40 pins
           MAEPF-27413-A  
						

							6881094C31-ENovember 16, 2006
Theory of Operation: VOCON Board3-17
Figure 3-8.  VOCON Board Interconnections (only for NNTN5567)
The functional blocks consist of the following:
•Controller and Memory: The Patriot (U401), the dual-core processor with the microcontroller 
unit (MCU) and a digital signal processor (DSP), the SRAM (U403) and Flash (U402) memory 
devices.
•Audio and Power: The GCAP II (U501), a 5 Vdc linear regulator (U505), a 1.55 Vdc linear 
regulator (NNTN4717 VOCON kit only), the audio pre-amplifier (U502), the audio power 
amplifier (U503), and the dual EEPOT (U509).
NOTE:In kit NNTN5567 (Figure 3-8): the audio, power, and digital support are all embedded into 
the MAKO IC (U501).
•Interface Support: The digital-support IC Flipper (U301), ESD protection circuitry, and side 
connector interface circuitry.
NOTE:Refer to Table 8-2, “List of VOCON Schematics and Board Overlays,” on page 8-1 for a listing 
of VOCON schematics that will aid in the following discussion.
3.2.1.1  Universal Connector J101
This is a 40-pin connector that mates with the universal flex on the housing. A majority of the lines on 
the connector are for user interface: emergency and side buttons (pin 14), monitor button (pin 17), 
secure/clear switch (pin 23), frequency switch (pins 24, 25, 26, and 27), volume knob (pin 31), and 
the three-position switch (pin 34). The LEDs on the universal flex are controlled through pins 20, 21, 
and 22. Connections to the external accessory connector, which include serial communication data 
lines, external audio, and option select lines for controlling audio modes, are present at pins 1 
through 13. Switched battery voltage (B+SENSE) is provided on pin 32. Most of the pins at this 
connector have ESD protection devices and components.
SRAM
1MByte INTERFACE SUPPORT
ESD Protection and
Side Connector
CircuitryASIC
Clocks and Side
Connector Support
VOCON
Board
CONTROLLER AND MEMORY
FLASH
8MBytes
Dual-Core
Processor
MCU and DSPKeypad
22 pins
Display
22 pins
Encryption
40 pins AUDIO AND POWER
RF
26 pins
Universal
40 pinsMAKO IC
Voltage Regulators
Audio Pre-amp
Power Amp
Clocks and 
Digital Support 
						

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3-18Theory of Operation: VOCON Board
3.2.1.2  Encryption Connector J701
This 40-pin connector provides the interface between the VOCON board and the encryption module. 
Two voltages are provided to the encryption board: UNSWB+ and SWB+. The SAP SSI lines, serial 
communication data lines, and general-purpose I/O lines from the Patriot IC are included in the 
interface to the encryption board. A number of jumpers are present on some of the lines so that the 
VOCON board configuration to the encryption board can be changed depending on the encryption 
type present.
3.2.1.3  Keypad Module Connector P107
This 22-pin connector mates the VOCON board to the keypad module flex used on Model II and III 
radios. The keypad module is provided with 5 volts (pins 7 and 8) for the LEDs. The LEDs are 
activated by the signal at pin 6, BL_EN. The row signal lines (pins 13, 14, 15, 16, 17, 18, and 19) and 
column signal lines (pins 1, 2, and 3) are all at the dual-core processor’s GPIO voltage.
3.2.1.4  RF Interface Connector P201
This is a 26-pin compression connector that interfaces between the VOCON board and the 
transceiver board. See Section 3.1.1.2 “ VOCON Connector P1,” on page 3-3 for a detailed 
description of the interface between the VOCON and transceiver boards through P201. Ground clip 
M202 is used on the bottom side of the VOCON board to contact the transceiver shield. This 
additional connection provides a consistent, common ground with the VOCON board and the radio 
chassis.
3.2.1.5  Display Module Connector P301
This 22-pin connector mates the VOCON board to the display module flex used on Model II and III 
radios. The NTN9564 VOCON kit has a parallel data interface to the display module. In this design, 
two voltages are provided to the display module: 1.8 V and 3 V. The display’s parallel data lines (pins 
9, 10, 11, 12, 13, 14, 15, and 16), chip select line (pin 5), read/write line (pin 8), register select line 
(pin 7), and parallel/serial configuration line (pin 4) are at 1.8-V logic levels.
The NNTN4563 and NNTN4819 VOCON kits have a serial data interface to the display module. In 
this design, only 3 V is provided to the display module on pins 17 and 18. The display’s serial data 
line (pin 16), serial clock line (pin 15), chip select line (pin 5), and register select line (pin 7) are at 3 V 
logic levels. The NNTN4717 and NNTN5567 VOCON board has a serial data interface to the display 
module, and all the lines are at 2.9 V logic levels.
3.2.2 Controller and Memory
The controller and memory section contains the following components:
• Patriot IC (U401)
• Static RAM (SRAM) IC (U403)
• Flash memory IC (U402)
The Patriot IC acts as both the microcontroller unit (MCU) and the digital signal processor (DSP) for 
the radio. The MCU controls receive/transmit frequencies, power levels, display programming, user 
interface (PTT, keypad, channel select, etc.), and programming of ICs, as well as other functions. 
The DSP performs voice encoding and decoding, audio filtering, volume control, PL/DPL encode 
and alert-tone generation, squelch control, and receiver/transmitter filtering, as well as other 
functions.
The Patriot IC executes a stored program located in the Flash memory device. The SRAM, a volatile 
device, is used as working memory and shares the address and data bus with the Flash memory 
device. 
						

							6881094C31-ENovember 16, 2006
Theory of Operation: VOCON Board3-19
NOTE:Refer to Table 8-2, “List of VOCON Schematics and Board Overlays,” on page 8-1 for a listing 
of VOCON schematics that will aid in the following discussion.
3.2.2.1  Patriot IC U401
The Patriot IC U401 is a dual-core processor that contains both a 32-bit microcontroller unit (MCU) 
and a 16-bit digital signal processor (DSP) in one IC package. It comes in a 256-pin, ball-grid array 
(BGA) package with 1mm pitch solder balls. On the NTN9564, NNTN4563, and NNTN4819 VOCON 
boards, the dual-core processor is supplied with two voltages: 1.8 V (E401) and 3 V (E402). The 
1.8 V supply is used as the core voltage, as well as the interface voltage, to the memory devices and 
display (1.8 V display interface only for the NTN9564 VOCON board). Most of the pins on the Patriot 
IC operate from the 3 V supply.
The NNTN4717 kit uses a new dual-core processor which requires some different operating 
voltages. The 1.8 V supply is used as the interface to the memory devices, unchanged from the 
original processor.  A 1.55 V supply is used for the core voltage and the clock amplifier module. The 
remaining pins of the processor use a 2.9 V supply.
NOTE:GPIO voltage for the NTN9564, NNTN4563, and NNTN4819 VOCON boards is 3.0 V.
NOTE:GPIO voltage for the NNTN4717 and NNTN5567 VOCON board is 2.9 V.
Two main clocks are provided to the Patriot IC. The CKIH pin (C452) is provided a 16.8 MHz sine 
wave. This is the most important clock since it is internally used to generate the clocks for both the 
MCU and DSP cores, as well as most of the peripherals. A 3 V peak-to-peak 32 kHz square wave 
(32 kHz test point) is generated by the Flipper IC U301 and supplied to the CKIL pin on the Patriot 
IC. While not as widely used as the 16.8 MHz clock, the 32 kHz clock is needed by some 
components in the Patriot including the reset circuitry.
3.2.2.1.1  Microcontroller Unit (MCU)
The MCU portion of the Patriot IC has 22.5k x 32 bits of internal RAM and 1k x 32 bits of internal 
ROM, which is used for the bootstrapping code. The MCU has several peripherals including an 
External Interface Module (EIM), the Multiple Queue Serial Peripheral Interface (MQSPI), two 
Universal Asynchronous Receiver/Transmitter (UART) modules, and the One-Wire Interface 
module. The MCU communicates internally to the DSP through the MCU/DSP Interface (MDI).
External Interface Module (EIM)
The External Interface Module (EIM) is the MCU interface to the SRAM U403 and Flash Memory 
U402, as well as the display (only for the NTN9564 VOCON kit). The EIM lines include 24 external 
address lines, 16 external bi-directional data lines, 6 chip selects lines, read/write line, and output 
enable line among others. All of the EIM lines operate at 1.8-V logic levels, and the EIM operates at 
the MCU clock speed.
Multiple Queue Serial Peripheral Interface (MQSPI)
The Multiple Queue Serial Peripheral Interface (MQSPI) is the MCUs programming interface to other 
ICs. The Patriot IC has two independent SPI busses, and each has its own clock line (test points 
SCKA and SCKB), data-out line (test points MOSIA and MOSIB), and data-in line (test points MISOA 
and MISOB). There are 10 SPI chip selects (SPICS) that are programmable to either SPI A, the 
transceiver board SPI bus, or to SPI B, the dedicated VOCON SPI bus. 
						

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3-20Theory of Operation: VOCON Board
The devices on the SPI A bus include the PCIC and FracN IC on the SPICS4 (R131), the Abacus III 
IC on SPICS5 (R126), an analog-to-digital converter (ADC) on SPICS6 (R133), and the serial 
EEPROM on SPICS7 (R132). The two SPI B chip selects are for the GCAP II IC U501 on SPICS2 
(R539) and the Flipper IC U301 on SPICS3. On the NNTN4563, NNTN4819, and NNTN4717 
VOCON boards, two additional SPI chip select lines are used for the display: SPICS0 (R442) and 
SPICS1 (U407 pin 14). On NNTN5567, one SPI B chip select is used for the MAKO IC U501 on 
SPICS2 (TP_MAKO_CE). See Section 3.2.3.7 “ MAKO IC U501 (for NNTN5567),” on page 3-27 for 
more information on MAKO IC U501. All of the SPI module lines operate at GPIO voltage logic 
levels.
There are several devices on the transceiver board that only have one bi-directional SPI data line. 
Components U404, U405, and U406 are configurable by MCU GPIO pin TOUT13 (MISOA_SEL) to 
route the data line to the appropriate pin on the Patriot IC depending on which SPI device is being 
accessed.
Universal Asynchronous Receiver/Transmitter (UART)
The Patriot IC has two Universal Asynchronous Receiver/Transmitter (UART) modules. UART1 
handles the RS232 lines while UART 2 is connected to the SB9600 lines. Each UART has a receive 
data line (URXD), a transmit data line (UTXD), and hardware flow control signals (RTS–request to 
send) and (CTS–clear to send). All UART lines operate at GPIO voltage logic levels. The translation 
to 5 V logic levels for the accessory side connector is discussed in the Flipper section.
One-Wire Interface
The MCU has a One-Wire Interface module that is used to communicate to a One-Wire device like a 
USB cable or a smart battery using the Dallas Semiconductor protocol. This module has one 
external pin, OWIRE_DAT (Q504 pin 2), and it uses a GPIO voltage logic level.
3.2.2.1.2  Digital Signal Processor (DSP)
The DSP portion of the Patriot IC has 84k x 24 bits of program RAM and 62k x 16 bits of data RAM. 
The DSP has its own set of peripherals including the Baseband Interface Port (BBP), the DSP Timer 
module, and the Serial Audio CODEC Port (SAP). Additionally, the DSP shares some peripherals 
with the MCU, including the USB interface and the General Purpose Input/Output module (GPIO).
Baseband Interface Port (BBP)
The Baseband Interface Port (BBP) module is the DSP’s serial synchronous interface (SSI) to the 
transceiver board. The BBP has independent sections for the receiver and the transmitter. The 
receiver BBP pins include the receive data pin SRDB (R121), the receive clock signal pin SC0B 
(R124), and the receive frame synchronization (sync) signal pin SC1B (R123). The transmitters BBP 
pins include the transmit data pin STDB (R127), the transmit clock signal pin either SCKB (R125) or 
SCKB (TP_SCKB) in NNTN5567, and the transmit frame sync signal pin either SC2B (R119) or 
SC2B in NNTN5567. All BBP lines use GPIO voltage logic levels.
DSP Timer Module
While the BBP receive clock and frame sync signals are supplied by the Abacus III IC from the 
transceiver board, the BBP transmit clock and frame sync signals are generated by the DSP Timer. 
The BBP receive clock, connected to the DSP Timer input pin T10, is reference used to generate the 
BBP transmit clock and frame sync signals. These two signals, along with the BBP transmit data 
signal, are connected to the DAC on the transceiver board. For NNTN5567, the BBP transmit clock 
and frame sync signals are generated by the MAKO IC using the 16.8MHz clock (connected to the 
TCXO_IN M1 pin). 
						

							6881094C31-ENovember 16, 2006
Theory of Operation: VOCON Board3-21
Serial Audio CODEC Port (SAP)
The Serial Audio CODEC Port (SAP) module is the DSP’s serial synchronous interface (SSI) to the 
audio CODEC on the GCAP II IC. However, In NNTN5567, the audio CODEC is on the MAKO IC. 
The SAP also interfaces with the encryption module.
The SAP interface consists of four signals including the SAP clock line pin SCKA (component R405 
or R572 (for NNTN5567) ), the SAP frame sync line pin SC2A (component R406 or R573 (for 
NNTN5567) ), the SAP receive data line pin SRDA (component R402), and the transmit data line pin 
STDA (component R403). On the NTN9564, NNTN4563, and NNTN4819 VOCON boards, the SAP 
clock is generated by the Flipper IC U301, and is a 520 kHz, 3 V peak-to-peak square wave. The 
SAP frame sync signal is also generated by the Flipper IC, and is an 8 kHz, 3 V peak-to-peak square 
wave. 
On NNTN5567 Vocon board, the SAP clock is generated by the MAKO IC (U501) and is a 512 kHz, 
2.9V peak-to-peak wave. The SAP frame sync signal is generated by the MAKO IC U501, and is an 
8kHz, 2.9V peak-to-peak square wave. 
On the NNTN4717 VOCON board, the SAP clock is generated by the dual-core processor U401, 
and is a 256 kHz, 2.9 V peak-to-peak square wave. The SAP frame sync signal is generated by the 
dual-core processor U401, and is an 8 kHz, 2.9 V peak-to-peak square wave.
Universal Serial Bus (USB)
The Patriot IC USB peripheral, shared by the MCU and the DSP, provides the required buffering and 
protocol to communicate on the Universal Serial Bus. The Patriot IC supports USB slave 
functionality.
For receive data, the USB differentially decoded data comes from the Flipper IC URXD_RTS pin into 
the Patriot URTS1 pin, while the single-ended USB data positive signal goes to pin PA2_USB_VPIN, 
and the single-ended USB data minus signal goes to pin URXD1. The two data lines are used to 
detect the single-ended zero state.
On the NNTN5567 VOCON board, the receive data path is routed from the MAKO ICs (U501) 
integrated USB transceiver. Single ended positive data is generated at U501 pin B9 and is sent to 
the Partriot PA2_USB_VPIN pin. USB data minus comes from U501 pin C9 and is sent to URXD1 of 
the Patriot. 
For transmit data, the USB data comes out of the Patriot IC UTXD1 pin and goes to either the Flipper 
IC or MAKO IC (NNTN5567) TXD_USB_VPO pin. The USB transmit single-ended zero signal is 
generated from the Patriot IC PC0_USB_VMOUT pin.
General-Purpose Input/Output (GPIO) Module
The General-Purpose Input/Output (GPIO) module is shared by the MCU and the DSP. This module 
consists of four 16-pin bi-directional ports and a 15 pin bi-directional port. While some of the pins on 
these ports are being used for other functions (UART, SPI, SAP, BBP, and Interrupt pins), the 
remaining pins can be programmed to become GPIOs that can be used by either the DSP or the 
MCU. Each GPIO pin has up to 8 alternate output functions and up to 4 alternate input functions. 
This allows for the GPIO pins to be routed internally to pertinent Patriot IC modules. Additionally, the 
GPIO module adds selectable edge-triggered or level-sensitive interrupt functionality to the GPIO 
pins. Some examples of GPIO pins include the Audio PA control signals (EXT_SPKR_SEL, 
AUDIO_PA_EN, and AUDIO_MODE_SEL), the EEPOT control signals (EEPOT_INC*, 
EEPOT_U_D*, EEPOT_CS*, and EEPOT_CS_EXT*), and the LED control signals (RED_LED and 
GREEN_LED).