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C165UTAH
Architectural Overview
Data Sheet
43
2001-02-23
operation or open-drain operation via control registers. During the internal reset, all port
pins are configured as inputs.
All port lines have programmable alternate input or output functions associated with
them. PORT0 and PORT1 may be used as address and data lines when accessing
external memory, while Port 4 outputs the additional segment address bits A22/A19/
A17...A16 in systems where segmentation is used to access more than 64 KBytes of
memory. Port 6 provides optional bus arbitration signals (BREQ, HLDA, HOLD) and chip
select signals. Port 2 accepts the fast external interrupt inputs. Port 3 includes alternate
functions of timers, serial interfaces, the optional bus control signal BHE and the system
clock output (CLKOUT). Port 7 is used for general purpose I/Os. All port lines that are
not used for these alternate functions may be used as general purpose I/O lines.
Serial Channels
Serial communication with other microcontrollers, processors, terminals or external
peripheral components is provided by two serial interfaces with different functionality, an
Asynchronous/Synchronous Serial Channel (ASC) and a High-Speed Synchronous
Serial Channel (SSC).
ASC
is upward compatible with the serial ports of the Infineon 8-bit microcontroller
families and supports full-duplex asynchronous communication at up to 2.25 MBaud and
half-duplex synchronous communication at up to 4.5 MBaud @ 36 MHz CPU clock.
A dedicated baud rate generator allows to set up all standard baud rates without
oscillator tuning. For transmission, reception and error handling 4 separate interrupt
vectors are provided. In asynchronous mode, 8- or 9-bit data frames are transmitted or
received, preceded by a start bit and terminated by one or two stop bits. For
multiprocessor communication, a mechanism to distinguish address from data bytes has
been included (8-bit data plus wake up bit mode).
In synchronous mode, the ASC transmits or receives bytes (8 bits) synchronously to a
shift clock which is generated by the ASC. The ASC always shifts the LSB first. A loop
back option is available for testing purposes.
A number of optional hardware error detection capabilities has been included to increase
the reliability of data transfers. A parity bit can automatically be generated on
transmission or be checked on reception. Framing error detection allows to recognize
data frames with missing stop bits. An overrun error will be generated, if the last
character received has not been read out of the receive buffer register at the time the
reception of a new character is complete.
SSC
supports full-duplex synchronous communication at up to 18 Mbaud @ 36 MHz
CPU clock in SSC master mode and up to 9 MBaud @ 36 MHz in SSC slave mode. It
may be configured so it interfaces with serially linked peripheral components. A
dedicated baud rate generator allows to set up all standard baud rates without oscillator
tuning. For transmission, reception and error handling 3 separate interrupt vectors are
provided.