In my current application, I read periodically the CODE of a MB set as an extended transmission MB. In some cases, I read "0x0D" 1101 and this code is not available in the reference manual. Any idea what does this code 0x0D mean ?
The least significant bit in the CODE field represents the BUSY bit. So similarly as it is for RX codes this indicates BUSY condition for TX MBs. This is set by module during the “move-out” operation; when the MB is transferring to the SMB.
See Table 25-5. Message Buffer Code for Rx buffers and a note 1 below that table.
“Note that for Tx MBs (see Table 25-6), the BUSY bit should be ignored upon read, except when AEN bit is set in the MCR register.”
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