Motorola MTM800 User Manual page 54

4.1 - 20
RS232 and SB9600 Serial Interfaces
The configuration of the RS232 and SB9600 serial interfaces depends on the terminal setup. If no
expansion head is connected to the terminal, Patriot Bravo module UARTA provides either a 4-wire
RS232 or an SB9600 interface on the 20 pin accessory connector J0400.
If at power up pin BUSY_OUT on the accessory connector J0400 is connected to pin BUSY_IN, the
Patriot Bravo assumes that SB9600 equipment is connected and configures UARTA for the SB9600
interface. If both pins are not connected to each other at power up, the UARTA will be configured for
RS232 interface. The interface comprises lines RS232_TX, RS232_RX, RS232_CTS, RS232_RTS.
These lines are not buffered and at 0 or 3 volts level.
USB
The terminal is a 1.1 USB device with 12Mb/s. The interface comprises lines RS232_TX,
RS232_RX and RS232_RTS. When a USB cable is connected to the terminal via JB the USB
supply voltage is detected on line RS232_RTS and transferred to the controller via signal USB_INT.
The controller chooses between RS232 and USB interface via the signal USB_RS232 and switches
the IC U0408. When the USB mode is used, the signal line RS232_TX is switched to USB D+ and
the RX signal to D-. The USB signals are driven by the driver IC U0405. The RS232 lines to
expansion head are then disconnected to eliminate the influence of stub lines.
Note
When an expansion head is connected to the terminal, the serial interfaces on the 20 pin accessory
connector J0400 can not be used.
The UARTA is configured for an 8-wire RS232 interface, which is available on the 9 pin connector of
the expansion head. This interface has standard RS232 levels and can be connected to an external
data terminal.
In addition, the Patriot Bravo configures its QSPIB module to provide either a 4-wire RS232 or
SB9600 interface with 5 volts level on the 25 pin expansion head connector. If line MUX_CTRL_1 is
at 0 volt, the interface is switched to RS232 mode.
When the MUX_CTRL_1 line is at 3 volts, the interface is switched to SB9600 mode. The interface
comprises lines BUSY_IN, BUSY_OUT, RESET_OUT, and the QSPIB lines SPIB_MOSI,
SPIB_MISO, SPIB_CLK, SPIB_CS1_UART and is available on the 40 pin front connector J0500
with signals at 3 volts high level.
The Patriot Bravo uses the SB9600 interface to communicate with the motorcycle Enhanced Control
Head. If no motorcycle Enhanced Control Head is connected, the interface can be used to control
the terminal via the SB9600 protocol with an external control terminal.
THEORY OF OPERATION (TRANSCEIVER)