![](http://datasheet.mmic.net.cn/370000/PFR4200MAE40_datasheet_16728610/PFR4200MAE40_159.png)
Message Buffer Control, Configuration, Status and Filtering Register Set
MFR4200 Data Sheet, Rev. 0
Freescale Semiconductor
159
The received cycle counter matches an element of the buffer’s cycle filter register, if cycle filtering
is enabled;
Channel and frame ID criteria are met;
The received message has passed all error checks (see the PWD: Message Error Check chapter)
Transmit message buffer:
The content of the buffer is transmitted, when an element of the cycle filter register matches the current
cycle counter, and the frame ID matches the slot counter value.
For a detailed description of the CCFR registers, see
Section 3.2.3.8.4, “Cycle Counter Filter n Register,
n = [0:58] (CCFnR)
”.
3.4.3
Receive FIFO Filters
There are two filter sets available for FIFO filtering:
One FIFO acceptance filter set, comprising the following registers:
— FIFO acceptance filter message ID value register
(see
Section 3.2.3.8.5, “FIFO Acceptance Filter Message ID Value Register (FAFMIDVR)
”)
— FIFO acceptance filter message ID mask register
(see
Section 3.2.3.8.6, “FIFO Acceptance Filter Message ID Mask Register (FAFMIDMR)
”)
One FIFO rejection filter set, comprising the following registers:
— FIFO rejection filter frame ID value register
(see
Section 3.2.3.8.8, “FIFO Rejection Filter Frame ID Value Register (FRFFIDVR)
”)
— FIFO rejection filter frame ID mask register
(see
Section 3.2.3.8.9, “FIFO Rejection Filter Frame ID Mask Register (FRFFIDMR)
”)
The channels, from which the received frame will be accepted or rejected by the FIFO acceptance/rejection
filters, are specified by the FAFCHR register (see
Section 3.2.3.8.7, “FIFO Acceptance/Rejection Filter
Channel Register (FAFCHR)
”).
NOTE
The information from a received frame will be stored in the FIFO provided
the following conditions are met:
The receive message buffer filtering did not succeed, i.e. none of the
configured receive message buffers has a matching filter.
The message ID is accepted by the configured acceptance filter set.
The frame ID is not rejected by the configured rejection filter set.
NOTE
Frame ID filtering and message ID filtering can be enabled/disabled
independently of each other by setting the masks and values appropriately: