PCF8820U Philips Semiconductors, PCF8820U Datasheet - Page 15

• Manufacturer Part Number: PCF8820U
• Description: 67 x 101 Grey-scale/ECB colour dot matrix LCD driver
• Manufacturer: Philips Semiconductors

Philips Semiconductors
7.18
The I
between different ICs or modules. The serial data input line
and serial data output line are connected together, so
representing the Serial Data (SDA) line. See Section 13.4
for layout considerations. The SDA line and the Serial
Clock Line (SCL) line must be connected to a positive
supply voltage via a pull-up resistor. Data transfer may be
initiated only when the bus is not busy.
7.18.1
One data bit is transferred during a clock pulse period. The
data on the SDA line must remain stable during the HIGH
period of the clock pulse, otherwise any change in the data
within this period will be interpreted as a control signal
(see Fig.11).
2000 Dec 07
handbook, full pagewidth
handbook, full pagewidth
67 101 Grey-scale/ECB colour dot matrix
LCD driver
2
C-bus allows bidirectional data communication
I
2
C-bus interface
B
IT TRANSFER
SDA
SCL
START condition
SDA
SCL
S
Fig.12 Definition of START and STOP conditions.
data valid
data line
stable;
Fig.11 Bit transfer.
15
allowed
change
of data
7.18.2
Both data and clock lines are HIGH when the bus is not
busy (see Fig.12).
A START condition (S) occurs when the data line goes
from HIGH-to-LOW while the clock is HIGH.
A STOP condition (P) occurs when the data line goes from
LOW-to-HIGH while the clock is HIGH.
START
STOP condition
AND
MBC621
STOP
P
CONDITIONS
MBC622
SDA
SCL
Product specification
PCF8820