DSP 104-plus, Reference Manual

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158004.B00 21
3.2 SUPER I/O CHIP
Many of the peripheral functions are implemented in a single chip, the "Super I/O"
chip. This is the PC97317 from national Semiconductor. The following functions are
included in the PC97317:
•
Two serial ports (operating as COM2 and COM3).
•
A printer port.
•
A keyboard controller (providing a PS/2 mouse as well as the keyboard)
•
A floppy disk controller.
•
A real time clock with CMOS SRAM.
•
Several general-purpose I/O bits, used on the TP400 as the "Utility Register".
Each of these functions (except the general purpose I/O) have their own I/O
addresses, allocated at the same locations as in every PC. In addition, the PC97317
has its own set of configuration registers, which can be used by the BIOS to enable
or disable each function, assign I/O addresses, place the functions in low power
modes etc.
3.3 EXTRA UART
The Super I/O chip contains two serial ports; two further serial ports are provided by
an additional dual UART chip. This chip provides the COM3 and COM4 serial ports.
The chip selects for these two ports are in turn generated by two of the
programmable chip select registers within the Super I/O chip.
Further details of all four serial ports are given in section 3.4.
3.4 SERIAL PORTS
The TP400 features four serial ports that are accessed as COM1, COM2, COM3 and
COM4. The first three are RS-232 ports. COM4 provides TTL level transmit and
receive data signals only. Additionally the COM2 port can be configured for RS-485
operation.
3.4.1 Signals, Addressing and Interrupts
The serial ports are hardware and software compatible with the serial ports used on
PCs, and all PC communications software packages should work with the serial
ports. The UARTs are 16C550 compatible and thus provide a 16 byte transmit and
receive FIFOs.
The COM1 and COM2 UARTs are contained within the PC97317 Super I/O chip. The
COM3 and COM4 UARTs are contained within an additional dual UART chip.
Connection is made to the COM1 and COM2 serial ports via the 50-way J4
connector. If you are using a TCDEVPLUS these serial ports are available through
the standard 9 pin D-Type connectors at J4 (COM1) and J5 (COM2). These
connectors are pin compatible with all PC computers.