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Serial bus analysis
R&S
®
RTB2000
227
User Manual 1333.1611.02 ─ 11
"Frame Start"
Sets the trigger to the start of the message:
●
For SPI with CS, the frame starts when the chip select signal CS
changes to the active state.
●
For SPI without CS, the frame starts when the idle time has
expired.
"Frame End"
Sets the trigger to the end of the message.
●
For SPI with CS, the frame ends when the chip select signal CS
changes to the inactive state.
●
For SPI without CS, the frame ends when the idle time has
expired after the last clock and no new clock appeared during that
time.
"Bit <x>"
Sets the trigger to the bit number specified with
"Serial Pattern" Expands the trigger setup dialog to configure the bit pattern to be trig-
gered at. Set
to define the pattern, and
on page 227 to define the pat-
tern position.
Remote command:
Bit Offset
Specifies the number of bits before the first bit of the pattern. These bits are ignored.
The first bit after frame start is Bit
1. For example, with bit offset = 2, Bit 1 and Bit 2 are
ignored, and the pattern starts with Bit 3.
If "SPI Trigger" is set to "Bit <x>", the trigger is set to the next bit that follows the offset
bits. For example, if the bit offset is 4, the instrument triggers on the start of the 5th bit.
Remote command:
Number of Bits
Defines the length of the serial pattern in bits.
Note:
Entering data bits beyond the specified length of the pattern automatically
adjusts the "Number of Bits" to include all entered bits.
Remote command:
Data
Specifies the data pattern if "SPI Trigger" is set to "Serial Pattern". When the instru-
ment detects the specified data pattern, it sets the trigger to the first bit of this pattern.
An example of pattern definition is shown in
.
To enter the binary value of any bit, tap this bit. To enter the hexadecimal value, tap
one of the nibbles (half byte) in the lower data line.
If a nibble (half byte) contains 1, 2 or 3 "X" bits (don't care), the nibble value is repre-
sented by the character "$". If all 4 bits of a nibble are "X", the nibble itself is "don't
care", represented by the character "X".
SPI bus (option R&S
RTB-K1)