PCF8811U/2DA/1 NXP [NXP Semiconductors], PCF8811U/2DA/1 Datasheet - Page 36

• Manufacturer Part Number: PCF8811U/2DA/1
• Description: 80 x 128 pixels matrix LCD driver
• Manufacturer: NXP [NXP Semiconductors]

NXP Semiconductors
12. Instructions
PCF8811_4
Product data sheet
11.3 Command decoder
The data pointer is automatically updated and the data is directed to the intended
PCF8811 device. If the D/C bit of the last control byte was set to logic 0, these command
bytes will be decoded and the setting of the device will be changed according to the
received commands. The acknowledgement after each byte is made only by the
addressed PCF8811. At the end of the transmission the I
condition (P) and switches back to the F/S-mode, however, to reduce the overhead of the
master code, it is possible that a master can link a number of Hs-mode transfers,
separated by repeated START conditions (Sr).
The command decoder identifies command words that are received on the I
The most significant bit of a control byte is the continuation bit Co. If this bit is at logic 1, it
indicates that only one data byte, either command or RAM data, will follow. If this bit is at
logic 0, it indicates that a series of data bytes, either command or RAM data, may follow.
The DB6 bit of a control byte is the RAM data/command bit D/C. When this bit is at logic 1,
it indicates that a RAM data byte will be transferred next. If the bit is at logic 0, it indicates
that a command byte will be transferred next.
The PCF8811 interfaces via an 8-bit parallel interface, two different 3-line serial interfaces,
a 4-wire serial interface or an I
require the display clock.
Data accesses to the PCF8811 can be broken down into two areas: those that define the
operating mode of the device, and those that fill the display RAM.
In the case of the parallel and 4-wire SPI interfaces, the distinction is the D/C pad. When
the D/C pad is at logic 0, the chip will respond to instructions as defined in
the D/C bit is at logic 1, the chip will send data to the RAM.
When the 3-wire SPI, the 3-wire serial interface or the I
distinction between instructions which define the operating mode of the device and those
that fill the display RAM, is made respectively by the display data length instruction (3-line
SPI) or by the D/C bit in the data stream (3-line serial interface and I
There are 4 types of instructions. Those which:
In normal use, category 3 instructions are used most frequently.
1. Define the PCF8811 functions, such as display configuration etc.
2. Set internal RAM addresses
3. Perform data transfer with internal RAM
4. Others.
•
•
pairs of bytes: information in second byte, first byte determines whether information is
display or instruction data
Stream of information bytes after Co = 0: display or instruction data depending on last
D/C
Rev. 04 — 27 June 2008
2
C-bus interface. Processing of the instructions does not
80 x 128 pixels matrix LCD driver
2
C-bus interface is used, the
2
C-bus master issues a STOP
2
C-bus interface).
PCF8811
© NXP B.V. 2008. All rights reserved.
Table
2
C-bus:
10. When
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