From: Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx> Use table markup to show the PGN structure. Signed-off-by: Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx> --- Changes v1 -> v2: - add descrption for the bit position Documentation/networking/j1939.rst | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/Documentation/networking/j1939.rst b/Documentation/networking/j1939.rst index faf2eb5c5052..bd1584ec90f9 100644 --- a/Documentation/networking/j1939.rst +++ b/Documentation/networking/j1939.rst @@ -71,10 +71,14 @@ PGN The PGN (Parameter Group Number) is a number to identify a packet. The PGN is composed as follows: -1 bit : Reserved Bit -1 bit : Data Page -8 bits : PF (PDU Format) -8 bits : PS (PDU Specific) + + ============ ============== =============== ================= + Bit position of PGN fields in the 29-bit CAN identifier + ---------------------------------------------------------------- + 25 24 23 ... 16 15 ... 8 + ============ ============== =============== ================= + R (Reserved) DP (Data Page) PF (PDU Format) PS (PDU Specific) + ============ ============== =============== ================= In J1939-21 distinction is made between PDU1 format (where PF < 240) and PDU2 format (where PF >= 240). Furthermore, when using the PDU2 format, the PS-field -- 2.17.0
