Motorola Astro Xts5000 Detailed 6881094c31 E Manual

November 16, 20066881094C31-E
3-32Theory of Operation: VOCON Board
The USB transmitter is enabled when the RS232_USB* and USB_TXENAB signals are both driven 
low by the dual-core processor. The single-ended data is output from the dual-core processor on the 
UTXD1_USB_VPO pin and goes to USB1_DAT_TXD on U501. The data is driven out differentially 
on the USB1_DP and USB1_DM pins, which go to the side connector. The dual-core processor 
sends the single-ended zero signal from pin USB_VMO to the USB1_SE0...

6881094C31-ENovember 16, 2006
Theory of Operation: VOCON Board3-33
Several components on the VOCON board protect the circuitry from ESD. The side connector signal 
lines have ESD protection components on them since they are exposed. These protection 
components include:
• 5.6-V zeners VR205, VR206, VR220, and VR221 on the SB9600 lines, RS232 lines, 
microphone lines, and option-select lines
• 12-V zeners VR201, VR203, and VR209 on the internal and external speaker audio lines
• 13-V zener VR204 on the...

November 16, 20066881094C31-E
3-34Theory of Operation: VOCON Board
3.2.4.4  Universal Connector Interface Circuitry
See Figure 8-63, “NTN9564B VOCON Universal Connector Circuit,” on page 8-97 for schematic 
details of the following discussion.
Some important components on the universal connector interface are two op-amps. The first op-
amp, U201, is used as a comparator for the option-select 1 line. The comparator threshold is 
determined by the voltage-divider network of R257 and R258. Similarly, the...

6881094C31-ENovember 16, 2006
Theory of Operation: VOCON Board3-35
Most of the signals are extensions of circuits described in other areas of this manual. However, there 
are two option select pins (see Table 3-5) used to configure special modes: Option Select 1 and 
Option Select 2. These pins are controlled by accessories connected to the universal connector. 
Table 3-5 outlines their functions as defined at the universal connector. In the case of the XTS 
Vehicular Adapter (XTVA), Option Select 1 pin...

November 16, 20066881094C31-E
3-36Theory of Operation: VOCON Board
3.2.4.6  Keypad Module
The keypad module is either a 6- x 3-button (Model III) or a 2- x 3-button (Model II) module with 
backlighting.
The keypad module is connected to the VOCON board through flex connector J107. The keypad is 
read though a row-and-column matrix made up of ROW1, ROW2, ROW3, ROW4, ROW5, ROW6, 
and COL1, COL2, and COL3. When a key is pressed, a row and a column are connected to each 
another. The Patriot IC determines a...

6881094C31-ENovember 16, 2006
Theory of Operation: VOCON Board3-37
LED D1 is the TX/RX indicator. LEDs D2 through D6 are used for backlighting the frequency knob.
U1 is a binary-coded switch. The output pins from U1, which are connected to GPIO pins on the 
Patriot IC, provide a four-bit binary word (signals RTA0, RTA1, RTA2, and RTA3) to the MCU, 
indicating to which of the 16 positions the rotary is set. This switch provides an additional output, 
TG2, which is typically used for coded or clear mode...

November 16, 20066881094C31-E
3-38Theory of Operation: VOCON Board
The other clock supplied to the Patriot IC is a 32.768 kHz square wave. This clock is generated by 
the Flipper IC internal oscillator and an external 32.768 kHz crystal Y301 and is connected to the 
Patriot IC CKIL pin.
3.2.5 VOCON Audio Paths
This section describes the VOCON transmit and receive audio paths. See Figure 8-67, “NTN9564B 
VOCON Audio and DC Circuits,” on page 8-101 for schematic details of the following discussion.
3.2.5.1...

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3.2.5.2  Transmit Audio Path (for kit NNTN5567A)
Refer to Figure 3-14. The single-ended internal microphone audio enters the VOCON board through 
pin 8 of the M102 contact, and the internal microphone bias is set by circuitry that includes C550, 
R550 and R552. The internal microphone signal is connected to the INT_MIC_P pin, which is the 
input terminal on the Mako IC internal op-amp G1 after the signal is multiplexed. The gain of the G1...

November 16, 20066881094C31-E
3-40Theory of Operation: VOCON Board
3.2.5.3  Receive Audio Path
Refer to Figure 3-15. The receive audio data comes from the Abacus III IC U500 through the RF 
interface connector P201 pin 12 (RX_DATA) to the Patriot IC SRDB pin. The DSP decodes the data 
and sends it out through the CODEC_RX line to the GCAP II IC RX pin. The CODEC filters and 
converts the digital data into an analog audio signal, which, in turn, is sent to a programmable gain 
amplifier. The Patriot IC...

6881094C31-ENovember 16, 2006
Theory of Operation: VOCON Board3-41
The dual-core processor selects whether the amplified audio is routed to the internal speaker or the 
external speaker through the SPI lines based upon which amplifier is turned on as shown in the PA 
control block. The output audio is routed on Mako IC pins INT_SPKR_P and INT_SPKR_M for 
internal and EXT_SPKR_P and EXT_SPKR_M for external speaker lines.
Figure 3-16.  VOCON Receive Audio Path (for kit NNTN5567)
3.2.6 Radio...