W78C354 Datasheet, PDF (18/44 Pages) Winbond – MONITOR MICROCONTROLLER

W78C354
E-4 Port 4
Port 4 is an output port. The W78C354 can write data to this port using SFR PORT4.
Int.Bus
Write to
Latch
Vcc
Internal
Pullup
D
Q
CL
Q
P4.0 to P4.6
Figure 4-1. Port 4 architecture
F. SPI (Synchronous Peripheral Interface) and RS232 Port
• P3.0 (RXD) and P3.1 (TXD) can be used as an SPI port (serial port mode 0 on the standard 80C32)
or an RS232 port (serial port mode 1, 2, or 3 on the standard 80C32).
• The SPI port can be used to communicate with an OSD chip, DAC, and so on.
• The RS232 port can be used to communicate with an auto-alignment system, by using a 18.432
MHz crystal. Maximum baud rate is 19200 bps.
G. DDC Port (Display Data Channel Port)
The DDC port is composed of the SIO1 and DDC1 ports, and the SIO1 port shares the DSDA pin with
the DDC1 port (as shown in Figure 5). The DDC port is designed to support DDC1, DDC2B, and
DDC2B+ applications.
G-1 SIO1 Port
SIO1 is an I²C serial I/O port. SIO1 provides a serial interface that meets the I²C bus specification
and supports all transfer modes from and to the I²C bus. The SIO1 port handles byte transfers
autonomously.
The W78C354 interfaces to the SIO1 port through the following four special function registers:
S1CON (SIO1 control register), S1STA (SIO1 status register), S1DAT (SIO1 data register), and
S1ADR (SIO1 address register). The SIO1 port interfaces to the DDC I²C bus via two pins: P1.2 /
DSCL (DDC I²C serial clock line) and P1.3/DSDA (DDC I²C serial data line). The output latches of
P1.2 and P1.3 must be set to "1" in order to enable the SIO1 port. For more detailed information,
refer to the description of the Philips I²C bus.
G-1.1 S1ADR (SIO1 Address Register) (DAH)
The W78C354 can read from and write to this 8-bit newly added SFR S1ADR. When the the SIO1
port is in a master mode, the content of this register is irrelevant. In slave mode, the seven most
significant bits must be loaded with the address that owns the slave.
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