Eurotech PXA320, User Manual

Page: 18 / 62

Graphics ClientM User Manual
110120-1000A
18
CAN 2.0B Bus
The GCM supports a direct connection to a CAN (Controller Area Network) bus compliant
with the CAN 2.0B specification. The CAN 2.0B bus provided on header J23 , page 44 is
driven by an on-board controller and includes a CAN transceiver, common mode filter,
and ESD protection.
1-Wire Bus
A 1-Wire bus provides a low-speed, single-wire communication bus to external devices.
Typically, this bus is used to communicate with small inexpensive devices such as
batteries and security components. The PXA320 supports a 1-Wire bus on header J11 ,
page 35 . For electrical specifications, see PXA320 Processor , page 47 .
I
2
C Bus
I
2
C (Inter-IC) is a multi-master, two-wire synchronous serial bus for communications
between integrated circuits and for addressing peripherals in a system. The bus master
addresses devices using the data line and provides a synchronous clock for reading and
writing devices. Client devices respond only when queried by the master device.
The GCM uses the PXA320 as the I
2
C bus master to communicate with on-board
devices. In addition, connector J21 , page 40 includes an external connection to the I
2
C
bus.
The following diagram illustrates the I
2
C architecture on GCM. For electrical
specifications, see PXA320 Processor , page 47 .
I2C_SDA
I2C_SCL
ADSmartIO RTC
J21
Graphics ClientM
PXA320
Processor
3.3 V
1.2k 1.2k
The following table lists the addresses of the I
2
C devices.
Device Address Function
DS1307 1101 000 Real-time clock
ADSmartIO reserved Various I/O functions
The DS1307 supports a maximum bit rate of 100 kbps. Do not use the I
2
C bus at rates
faster than 100 kbps.