Microchip Technology APGDT001 User Manual
LIN Serial Analyzer User’s Guide Rev2.0
DS51675B-page 12
©
2008 Microchip Technology Inc.
3.3
TRANSACTION WINDOW
This window, shown in Figure 3-1, constantly monitors and display bus traffic when in
the “Display All” mode. Any message frames seen on the bus are shown, regardless of
the source.
the “Display All” mode. Any message frames seen on the bus are shown, regardless of
the source.
The data is displayed as it is seen on the bus without modification.
This section describes the window’s fields.
FIGURE 3-1:
MESSAGE FRAMES DISPLAY
3.3.1
TimeStamp
This field of the Transaction window displays the time, in seconds, since the last frame
was received. The value is reset to zero when the window is cleared.
was received. The value is reset to zero when the window is cleared.
The value can also be cleared by clicking on the “TimeStamp” column label.
3.3.2
ID (Identifier)
This field displays the ID byte, including the upper two parity bits.
3.3.3
Data
From zero to eight data bytes are displayed in this field. The data is in the hexadecimal
format (without the leading characters, ‘0x’), with the bytes separated by spaces.
format (without the leading characters, ‘0x’), with the bytes separated by spaces.
3.3.4
Checksum
The last field of a frame is the checksum. The checksum contains the inverted, eight-bit
sum with carry, over all data bytes or all data bytes and the protected identifier.
sum with carry, over all data bytes or all data bytes and the protected identifier.
3.3.5
ChkSumType
This field indicates whether a “classic” or “enhanced” equation was used for the check-
sum calculation. For messages sent via the Master Message group box, the type of
calculation is configured in the checksum portion of the Master Message group box
(see Section 3.8.3 “Checksum Group”).
sum calculation. For messages sent via the Master Message group box, the type of
calculation is configured in the checksum portion of the Master Message group box
(see Section 3.8.3 “Checksum Group”).
• Classic – Checksum calculation over the data bytes only. Used for the master
request frame, slave response frame and communications with LIN 1.x slaves.
An eight-bit sum with carry is equivalent to the sum of all values and subtracts
255 every time the sum is greater than or equal to 256.
255 every time the sum is greater than or equal to 256.
• Enhanced – Checksum calculation over the data bytes and the protected identifier
byte. Used for communication with LIN 2.x slaves.
The checksum is calculated both ways when a message frame is received. A match is
displayed either as “Classic” or “Enhanced”. If neither result matches the incoming
data, “ERROR” is displayed.
displayed either as “Classic” or “Enhanced”. If neither result matches the incoming
data, “ERROR” is displayed.
3.3.6
Baud
This field shows the actual, calculated bit rate observed during the Auto-Baud Detect
period of the current frame.
period of the current frame.