Intermec 074787-001 User Manual
Chapter 2 — Theory of Operation
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PB42 Portable Receipt Printer Service Manual
The SCC UART is shared with the Bluetooth module. Selection between
RS-232 and Bluetooth is accomplished with the SERIAL/BT* output.
(PE22) To enable the RS-232 transceiver and disconnect the Bluetooth
module set SERIAL/BT* to output high.
RS-232 and Bluetooth is accomplished with the SERIAL/BT* output.
(PE22) To enable the RS-232 transceiver and disconnect the Bluetooth
module set SERIAL/BT* to output high.
Cable Detection
When an active (powered) cable is inserted into or removed from the serial
jack, an interrupt on PC15 occurs. Interrupts on PC15 are handled by the
CPM interrupt controller (CPIC). A cable is inserted when PC15 is high.
jack, an interrupt on PC15 occurs. Interrupts on PC15 are handled by the
CPM interrupt controller (CPIC). A cable is inserted when PC15 is high.
To conserve power, set SERIAL/BT* high only when a serial cable is
detected.
detected.
Bluetooth Module
The Bluetooth module is mounted on the main board. The interface to the
module is the MPC875 SCC UART with hardware flow control. (TX, RX,
CTS, RTS) Two additional GPIO pins (PC12 and PE29) are connected to
the module.
module is the MPC875 SCC UART with hardware flow control. (TX, RX,
CTS, RTS) Two additional GPIO pins (PC12 and PE29) are connected to
the module.
PIO2 (connected to U1 PC12) provides the Bluetooth connection status. A
high level indicates that a connection is established. SPARE_PIO is an extra
signal whose function is programmable within the module.
high level indicates that a connection is established. SPARE_PIO is an extra
signal whose function is programmable within the module.
As described in the previous section, the SCC UART is shared between the
Bluetooth module and the RS-232 interface. The SERIAL/BT* (PE22)
output selects between the two. To communicate with the Bluetooth
module, SERIAL/BT* must be output low.
Bluetooth module and the RS-232 interface. The SERIAL/BT* (PE22)
output selects between the two. To communicate with the Bluetooth
module, SERIAL/BT* must be output low.
Holding the Bluetooth module reset line high disables the radio and puts it
into its lowest power mode. (<90
into its lowest power mode. (<90
μA) This reset line is connected to bit 7 of
the output shift register. For more information, see
. The module must be held in reset when the user
turns the radio off or when a wired connection is detected.
For information on the Bluetooth module itself, see its specification and/or
the PB42 software specification.
the PB42 software specification.
802.11g
Not yet implemented. The circuitry on the board is not tested and is only
there as a mechanical placeholder for when it is designed in.
there as a mechanical placeholder for when it is designed in.
Secondary Serial Test Port
The secondary serial test port is connected to the SMC UART. It can be
used to communicate with the processor when the SCC UART is being
used for either Bluetooth or RS-232 communication.
used to communicate with the processor when the SCC UART is being
used for either Bluetooth or RS-232 communication.
The test port is shared with the serial data receive line from the print
controller. The following illustration shows how the communication lines
are switched.
controller. The following illustration shows how the communication lines
are switched.