PC85133-1(2009) データシートの表示（PDF） - NXP Semiconductors.
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PC85133-1 Datasheet PDF : 41 Pages
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NXP Semiconductors
PCF85133
Universal LCD driver for low multiplex rates
7.16.5 Input filters
To enhance noise immunity in electrically adverse environments, RC low-pass filters are
provided on the SDA and SCL lines.
7.16.6 I2C-bus protocol
Two I2C-bus slave addresses (0111 000 and 0111 001) are reserved for the PCF85133.
The least significant bit of the slave address is bit R/W. The PCF85133 is a write-only
device and will not respond to a read access, so this bit should always be logic 0. The
second bit of the slave address is defined by the level tied at input SA0. Two types of
PCF85133 can be distinguished on the same I2C-bus which allows:
• Up to 16 PCF85133s on the same I2C-bus for very large LCD applications
• The use of two types of LCD multiplex on the same I2C-bus
The I2C-bus protocol is shown in Figure 15. The sequence is initiated with a START
condition (S) from the I2C-bus master which is followed by one of two possible PCF85133
slave addresses available. All PCF85133s with the corresponding SA0 level acknowledge
in parallel to the slave address, but all PCF85133 with the alternative SA0 level ignore the
whole I2C-bus transfer.
After acknowledgement, a control byte follows which defines if the next byte is RAM or
command information. The control byte also defines if the next byte is a control byte or
further RAM or command data.
In this way it is possible to configure the device and then fill the display RAM with little
overhead.
The command bytes and control bytes are also acknowledged by all addressed
PCF85133s connected to the bus.
The display bytes are stored in the display RAM at the address specified by the data
pointer and the subaddress counter; see Section 7.11 and Section 7.12.
The acknowledgement after each byte is made only by the (A0, A1 and A2) addressed
PCF85133. After the last (display) byte, the I2C-bus master issues a STOP condition (P).
Alternatively a START may be asserted to RESTART an I2C-bus access.
PCF85133_1
Product data sheet
Rev. 1 — 17 February 2009
© NXP B.V. 2009. All rights reserved.
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