AT AT-LA500, Руководство пользователя

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AT-LA500 – U
SER MANUAL
R
ELEASE
3.4 – JUNE 2009 32
I
2
C Trigger
In this mode, the AT-LA500 can trigger when a selected event occurs on a I
2
C (Inter Integrated
Circuit) bus. Furthermore, the acquired data are decoded and shown in the Waveform View and
State Listing windows.
To set up the AT-LA500 for an I
2
C acquisition, the following steps are required:
•
Connect a Passive Probe or a High-Z Probe to the pod A. In this case you also have to
correctly set the threshold voltage in the
Probes tab of the Settings window;
•
Connect at least one grounded pin (white wires) to the ground of the board to test;
•
Connect the
Channel 0
(black wire) to the
SDA
line of the I
2
C bus to test;
•
Connect the Channel 1 (brown wire) to the SCL line of the I
2
C bus to test.
Note : It is not possible to use a Low-C Probe to analyze an I
2
C bus: this could prevent the system
under test to work properly.
The I
2
C trigger has 2 different options: Address and Address&Data. These options are selectable by
using the I2C Trigger Type control.
Address
In this mode, the AT-LA500 can trigger when the I
2
C bus addresses one or more peripheral.
In the Trigger On control, it is possible to choose which operation has to be triggered. The available
options are:
•
Read or Write : trigger on every operation on the bus;
•
Read : trigger when the bus is performing a read operation, ignoring the ACK bit;
•
Write
: trigger when the bus is performing a write operation, ignoring the ACK bit;
•
ACK R/W : trigger on every acknowledged operation on the bus;
•
ACK Read : trigger on an acknowledged read operation on the bus;
•
ACK Write
: trigger on an acknowledged write operation on the bus;
• NACK R/W
: trigger on every not acknowledged operation on the bus;
•
NACK Read : trigger on a not acknowledged read operation on the bus;
•
NACK Write : trigger on a not acknowledged write operation on the bus;