Eurotech Appliances zeus pxa270 Manuel D’Utilisation
ZEUS Technical Manual
Detailed hardware description
© 2007 Eurotech Ltd Issue D
58
I²C bus
The PXA270 I²C interface is brought out to the COMs connector J19. See the section
, page
, for connection details.
I²C bus is also used with the Quick Capture interface. See the section
, page
.
The following table lists the on-board I²C devices:
Device name
I²C address
External General Purpose I/O
0x20
On-board GPIO Expander 1
0x21
On-board GPIO Expander 2
0x22
Temperature Sensor (LM75A)
0x48
RTC (Intersil ISL1208)
0x6F
Config EPROM
0x50-0x57
The I²C unit supports a fast mode operation of 400KB/s and a standard mode of
100KB/s.
Fast-mode devices are downward compatible and can communicate with standard-
mode devices in a 0 to 100KB/s I²C bus system. As standard-mode devices, however,
are not upward compatible, they should not be incorporated in a fast-mode I²C bus
system as they cannot follow the higher transfer rate and unpredictable states would
occur.
The I²C interface does not support the hardware general call, 10-bit addressing,
high-speed mode (3.4Mbit/s) or CBUS compatibility.
You should keep the total bus load below 200pF.
You should keep the total bus load below 200pF.