19 Serial communication
RX8130CE
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ETM50E-07
Seiko Epson Corporation
60
19.5 System configuration
All ports connected to the I
2
C-Bus must be either open drain or open collector ports in order to enable AND connections
to multiple devices.
SCL and SDA are both connected to the VIO line via a pull-up resistance. Consequently, SCL and SDA are both held at
high level when the bus is released (when communication is not being performed).
Master
Transmitter/
Receiver
Slave
Transmitter/
Receiver
Other I
2
C-Bus device
CPU, etc.
RX8130CE
SDA
SCL
V
IO
Master
Transmitter/
Receiver
Slave
Transmitter/
Receiver
Figure 48 I
2
C-Bus connection
Any device that controls the data transmission and data reception is defined as a "Master".
and any device that is controlled by a master device is defined as a “Slave”.
The device transmitting data is defi
ned as a “Transmitter” and the device receiving data is defined as a receiver”
In the case of this RTC module, controllers such as a CPU are defined as master devices and the RTC module is
defined as a slave device. When a device is used for both transmitting and receiving data, it is defined as either a
transmitter or receiver depending on these conditions.