5
1. Introduction
The TS-SER4 is a PC/104 expansion card with four serial ports using the PC standard
16C550 type UARTs (with 16-byte FIFOs). All four COM ports support RS-232 levels
and two of these COM ports can optionally support RS-422/ RS-485 levels.
A flexible interrupt sharing design allows for a large number of COM ports using a
minimum number of interrupts. An interrupt status register allows rapid identification of
the interrupt source.
This product uses a multi-layer PCB with power and ground planes to minimize noise
and EMI issues. The TS-SER4 only requires a single 5V power supply.
2. PC/104 Bus Interface
The TS-SER4 features a 16-bit PC/104 bus interface that allows access up to 11 IRQ
lines. A lower cost version with an 8-bit PC/104 bus interface limits the interrupt
selection to 6 IRQ lines (IRQ3, IRQ4, IRQ5, IRQ6, IRQ7, and IRQ9). A Xilinx
programmable Logic Device (PLD) is used to decode the COM port addresses. This
allows for a great amount of flexibility in the standard product and allows for custom
configurations if they are necessary.
3. Serial
Ports
The two serial ports that are labeled COM_A and COM_B support RS-232 levels only.
These two ports support the full complement of standard RS-232 handshakes as shown
in Table 1.
The two serial ports labeled COM_C and COM_D support a subset of RS-232C
handshakes lines that is sufficient for the vast majority of applications. In addition these
two ports can optionally have RS-485/RS-
422 drivers. Table 2 lists the pin-outs for
these ports.
The serial ports all use 16C550 UARTs,
which provide 16 byte send and receive
FIFOs, reducing the CPU overhead of high-
speed serial communications.
The serial baud clock (common to all four
serial ports) is derived from the PC/104 OSC
(14.318 MHz) signal. If this signal is not
present on the bus (all Technologic Systems
products have this signal), it will be
necessary to add a 3.6864 MHz crystal
oscillator in the position labeled X1. This
supplemental crystal oscillator can also be
used to generate very high-speed baud rates
Pin #
RS-232 Signal
1
DCD
2 RX
data
3 TX
data
4 DTR
5 GND
6 DSR
7 RTS
8 CTS
9 RI
10 -
Pin #
RS-232 Signal
1
DCD
2 RX
data
3 TX
data
4 DTR
5 GND
6 DSR
7 RTS
8 CTS
9 RI
10 -
Table 1
Pin-out for COM_A and COM_B Headers
Содержание TS-SER4
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