Usb Bus; Figure 3-47. Patriot Ic (U100) Uart Configuration - Motorola ASTRO Digital XTL 5000 Detailed Service Manual

Theory of Operation: Controller Section
The Patriot IC also requires a 32 kHz square-wave clock, provided at the CKIL (J7) pin. This clock is
generated by a 32 kHz crystal (Y0100), with supporting circuitry for oscillation. This clock is utilized
only for the Patriot IC, and is used for reset capability and other Patriot IC functions.
Four additional clocks are also supplied to the daughtercard: a 20 kHz RX frame-sync clock, a
48 kHz TX frame-sync clock, a 1.2 MHz RX data clock, and a 2.4 MHz TX data clock. The
microprocessor also generates the digital audio bus clocks: a 512 kHz data clock and an 8 kHz
frame-sync clock.
3.8.7 RS-232 USB Bus
The XTL 5000 microcontroller in the Patriot IC (U100) has two internal UARTS that can be
configured for RS-232 data communication: UARTA and UARTB
Front connector
(50-pin) - J0401
Pins 25, 26
Pins 31, 31, 33, 34
Pins 27, 28, 29, 30
UARTA is configured for RS-232 data transmission by default, and its data transmission is routed
through an on-board RS-232 transceiver (U0305) to bring the data voltage levels up to EIA RS-232
standards before the data exits the front and rear of the radio. The U0305 is a two-driver, two-
receiver device, protected against ±15 kV electrostatic discharges.
For data output, UARTA transmits data from the microcontroller at 0-V and 2.85-V levels. This data is
sent on an asynchronous serial bus, which is routed to an on-board RS-232 transceiver (U0305) that
converts these low-voltage levels to -9 V and +9 V signal levels. This RS-232-formatted data is
routed out the front of the radio (J0401-27, J0401-28, J0401-29, J0401-30) and to the rear of the
radio (J0402-7, J0402-8, J0402-9, J0402-10).
For data input, U0305 can accept up to ±30-V signal levels. These high levels are converted inside
the U0305 down to 0-V and 5-V levels. Next these data levels are routed thru a buffer stage (U0303)
which lowers the data to 0-V and 2.85-V levels. This is the required voltage levels for the input into
the microcontroller.
6881096C74-B
PATRIOT
U100
UART A
MUX
SWITCH
USB
XCVR
U0304
RS232
Boot_TX, Boot_RX
XCVR
U0305

Figure 3-47. Patriot IC (U100) UART Configuration

(Figure
UART B
SB9600
Circuit
BUS+, BUS-, BUSY, RESET
USB+, USB-, USB_PWR
TXD, RXD, CTS, RTS
3-69
3-47).
Rear connector
(26-pin) - J2
Pins 2, 3, 9, 8
Pins 7, 6, 12
Pins 4, 5, 10, 11
MAEPF-27702-O
May 25, 2005