TECHNICAL REFERENCE___________________________________________________________
18 __________________________________________________________________ M210829EN-A
In the receive mode, the driver section of the transceiver is disabled by
the 1-state of the controller TXEN output, which is inverted via D14
PLD and connected to the transceiver pin 3. The receiver section of
the transceiver is permanently enabled and the received data
ARCRXINP is connected through D14 to the controller RXIN input.
The D14 contains a data filter, which is used to filter out short
transient states from the incoming serial data. The filter length is
approximately 320 ns.
During the transmit sequence, the controller enables the transmitter by
driving pin 3 high and the inverted transmit data from output pin P1 is
driven to the line by the transmitter. The enable and data signals
(ARCTXEN# and ARCTX) are connected to the transmitter via PLD
D14.
Serial Channels
The MPU112 has four serial channels for external serial
communication. All channels have RS232 compatible line drivers and
receivers.
- Channels 1 and 2 are provided by the Computer Module. Both
channels are supported by the internal baud rate generators.
- Channel 1 is used for testing and is connected to the front panel
connector and system connector.
- Channel 2 is the main system channel and is connected to the
system connector pins a30 (TXD2) and a31 (RXD2) with
handshake signals (DTR2, RTS2, DSR2 and CTS2). This channel
is normally used for main external RS232 compatible connection.
- Channels 3 and 4 are provided by the PLD D14. The channels have
programmable baud rate generators. Only two 8 bit modes of data
widths are supported: 8 bit data with no parity or 7 bit data with
even/odd parity. Receivers have 8 byte FIFOs, but the fifo control
mode is not used.