Eepot U509; Interface Support Section; Flipper Ic U301 - Motorola ASTRO XTS 5000 Detailed Service Manual

Detailed Theory of Operation
The SELECT pin (U503 pin 6) is used to switch the audio path between internal and external
speaker. The voltage on that pin is determined by the EXT_SPKR_SEL line from the Patriot IC and
the Q505 transistor. When the voltage at the SELECT pin is high (B+), the audio is routed to the
internal speaker lines. When the voltage at the SELECT pin is low (V_select < 0.5V), the audio is
routed to the external speaker lines.

4.3.3.5 EEPOT U509

The EEPOT is a digitally programmable potentiometer with 256 taps and a total resistance of
50 kohms. This 10-pin package contains two independent potentiometers, one for each microphone
line. The EEPOT resistance values are programmed by the Patriot IC GPIOs EEPOT_INC* (U509
pin 9) and EEPOT_U_D* (U509 pin 2). The EEPOT_INC* signal increments the resistance value up
or down, which depends on the EEPOT_U_D* signal. The EEPOT_CS* line (U509 pin 10) is
asserted when the internal microphone gain is being changed. Similarly, the EEPOT_CS_XST*
(U509 pin 1) is asserted for external microphone gain changes. The EEPOT is supplied with 3 volts.
4.3.4

Interface Support Section

The interface support section consists of the following:

• Flipper IC U301

• ESD protection circuitry
• Universal connector interface circuitry.
4.3.4.1 Flipper IC U301
See Figure 9-13. VOCON Flipper Circuit on page 9-19
discussion.
The Flipper IC U301 is an application-specific, integrated circuit (ASIC) device designed for the XTS
radio product line. The Flipper IC is contained in a 64-pin µBGA package with 0.8 mm pitch solder
balls. The Flipper IC is supplied with 5 volts and 3 volts, and it uses the 16.8 MHz clock (C307) as its
master clock. The Flipper IC is programmable by the Patriot IC through the SPI bus.
The Flipper IC supports many functions including the radio side connector interface, bi-directional
logic level translation, boot data path control, USB transceiver, One-Wire option detect support,
watchdog timer, 32 kHz oscillator with CMOS output, 13 MHz reference generation for the GCAP II
IC, and SSI clock and frame sync generator.
4.3.4.1.1 Side Connector Interface, Logic Level Translation, and Boot Data Path Control
The Flipper IC facilitates the interface to the radio's side connector. Some of the side connector lines
are at 5-volt logic levels, so the Flipper IC converts those lines to 3-volt logic levels to interface to the
Patriot IC, as well as the encryption module. These lines include the SB9600 bus busy line
LH_BUSY (TP207), the RS 232 CTS (TP208) and RTS (TP209) lines, the RS232 data-out line
(TP210), and the RS232 data-in line (TP211). The SB9600 data line uses an external, bi-directional,
3- to 5-volt translation circuit that includes Q303, D301, R325, R326, and R327.
Another function that the Flipper IC provides with these lines is boot data path control. The boot data
path is as follows: boot data-in is multiplexed onto the RS232 data-out line while the boot data-out is
multiplexed with the SB9600 data line. This alternate data path is used only to Flash code into a
radio for the first time. The Patriot IC, through the SPI bus, controls this feature.
68P81094C31-O
: VOCON Board
for schematic details of the following
4-19
April 15, 2002