PC87109VBE Nuvoton Technology Corporation of America, PC87109VBE Datasheet - Page 10

• Manufacturer Part Number: PC87109VBE
• Description: IC CONTROLLER ADV UART 32-LQFP
• Manufacturer: Nuvoton Technology Corporation of America

Specifications of PC87109VBE

• Features: Transmit Deferral
• Number Of Channels: 2, DUART
• Fifo's: 16 Byte
• Voltage - Supply: 5V
• With Irda Encoder/decoder: Yes
• With False Start Bit Detection: Yes
• With Modem Control: Yes
• Mounting Type: Surface Mount
• Package / Case: 32-LQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *PC87109VBE

2.0
2.1 Device Overview
The PC87109 is a serial communications element that
implements the most common infrared communications
protocols.
In addition to the infrared modes, the device provides a
UART mode of operation that is backward compatible to
the 16550 to support existing communications software.
The device includes two basic modules: the UIR (universal
infrared) module and the configuration module. The UIR
module implements all the communications functions while
the configuration module controls the enabling of the device
as well as the enabling the interrupt and DMA control
signals. The UIR module uses a register-banking scheme
similar to the one used by the 16550.
This minimizes the number of I/O addresses needed to
access the internal registers. Most of the communications
features are programmed via configuration registers placed
in banks 0 through 7. The main control and status
information has been consolidated into bank 0 to eliminate
unnecessary bank switching. A description of the device
operation is provided in the following sections.
2.2 UART Mode
This mode is designed to support serial data
communications with a remote peripheral device or modem
using a wired interface. The PC87109 provides transmit
and receive channels that can operate concurrently to
handle full-duplex operation. They perform parallel-to-
serial conversion on data characters received from the
CPU or a DMA controller, and serial-to-parallel conversion
on data characters received from the serial interface. The
format of the serial data stream is shown in figure 1-3. A
data character contains from 5 to 8 data bits. It is preceded
2.3 Sharp-IR Mode
This mode supports bi-directional data communication with
a remote device using infrared radiation as the transmission
medium. Sharp-IR uses Digital Amplitude Shift Keying
(DASK) and allows serial communication at baud rates up
to 38.4 Kbaud. The format of the serial data is similar to
the UART data format. Each data word is sent serially
beginning with a zero value start bit, an optional parity bit,
and ending with at least one stop bit with a binary value of
one. Sending a 500 kHz continuous pulse train of infrared
radiation signals a zero. A one is signaled by the absence
of any infrared signal. The PC87109 can perform the
Functional Description
START
5 to 8 DATA BITS
Figure 2-1. Serial Data Stream Format
10
by a start bit and is followed by an optional parity bit and a
stop bit. Data is transferred in Little Indian order (least
significant bit first).
The UART mode is the default mode of operation after
power up or reset. In fact, after reset, the 16450-
compatibility mode is selected. In addition to the 16450
and 16550 compatibility modes, an extended mode of
operation is also available. When the extended mode is
selected, the architecture changes slightly and a variety of
additional features will be made available. The interrupt
sources are no longer prioritized, and an auxiliary status
and control register replaces the scratch pad register. The
additional features include transmitter FIFO thresholding,
DMA capability, and interrupts on transmitter empty and
DMA event.
The clock for both transmit and receive channels is
provided by an internal baud generator that divides its input
clock by any divisor value from 1 to 2
clock frequency of the baud generator must be
programmed to be sixteen times the baud rate value. The
baud generator input clock is derived from a 24 MHz clock
through a programmable prescaler. The PRESL bits in the
EXCR2 register determine the prescaler value. Its default
value is 13. This allows all the standard baud rates, up to
115.2 Kbaud to be obtained. Smaller prescaler values will
allow baud rates up to 921.6 Kbaud (standard) and 1.5
Mbaud (non-Standard).
Before operation can begin, both the communications
format and the software must program baud rate. The
communications format is programmed by loading a control
byte into the LCR register, while the baud rate is selected
by loading an appropriate value into the baud generator
divisor register. The software can read the status of the
device at any time during operation. The status information
includes FULL/EMPTY state for both transmit and receive
channels, and any other condition detected on the received
data stream, like a parity error, framing error, data overrun,
or break event.
modulation and demodulation operations internally, or it can
rely on the external optical module to perform them.
The device operation, in Sharp-IR, is similar to the
operation in UART mode. The main difference being that
data transfer operation is normally performed in half-duplex
fashion. The MDSL bits in the MCR register control
selection of the Sharp-IR mode when the device is in
extended mode or by the IR_SL bits in the IRCR1 register
when the device is in non-extended mode. This prevents
legacy software, running in non-extended mode, from
spuriously switching the device to UART mode, when the
software writes to the MCR register.
PARITY
STOP
16
- 1. The output
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