CP3BT26 Datasheet, PDF (167/375 Pages) National Semiconductor (TI) – Reprogrammable Connectivity Processor with Bluetooth-R, USB, and CAN Interfaces

CP3BT26
www.ti.com
SNOSAE5D – FEBRUARY 2007 – REVISED DECEMBER 2013
By setting the BUFFLOCK bit in the configuration register, the receiving buffer is automatically locked after
reception of one valid frame. The buffer will be unlocked again after the CPU has read the data and has
written RX_READY in the buffer status field. With this lock function, software has the capability to save
several messages with the same identifier or same identifier group into more than one buffer. For
example, a buffer with the second highest priority will receive a message if the buffer with the highest
priority has already received a message and is now locked (provided that both buffers use the same
acceptance filtering mask).
As shown in Figure 19-18, several messages with the same ID are received while BUFFLOCK is enabled.
The filtering mask of the buffers 0, 1, 13, and 14 is set to accept this message. The first incoming frame
will be received by buffer 0. Because buffer 0 is now locked, the next frame will be received by buffer 1,
and so on. If all matching receive buffers are full and locked, a further incoming message will not be
received by any buffer.
Received ID 01010
10101010
Figure 19-18. Message Storage with BUFFLOCK Enabled
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