NXP Semiconductors MPC5644A, Reference Manual, Page: 1223 / 1735

Decimation Filter
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor 1223
26.5.16.2 Cascade Mode Data/Control Bus description
A separate data bus is used to cascade the filters. The bus content is presented in Figure 26-23 and the
signals descriptions are present below.
Cascade Middle and Tail blocks do not make input feed requests, either on PSI or slave-bus interfaces.
Similarly, cascade Head and Middle block do not make filtered (not integrator) output data requests, either
on PSI or slave-bus interfaces.
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
DFCIN/OUT_ST
OP
D
F
CIN/OUT_REQ
Reserved
DFCIN/OUT_FLUSH
DFCIN/OUT
_CTRL[1:0]
Res. DFCIN/OUT_TAG[3:0]
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
DFCIN/OUT_DATA[15:0]
Figure 26-23. Decimation filter cascade mode data bus
Table 26-30. Decimation filter cascade mode data bus field description
Field Description
0
DFCIN/OUT_STOP
Decimation Filter Cascade Input/Output Stop flag
The DFCIN/OUT_STOP bit indicates that a cascade bus driver block in a cascade
configuration is stopped. When the block is configured as Cascade Middle or Tail, it only
stops when this bit is asserted.
1
DFCIN/OUT_REQ
Decimation Filter Cascade Request
The DFCIN/OUT_REQ bit indicates that a cascade bus driver block in a cascade
configuration has data ready to be sent. The driven block responds to the request asserting
its decfil_cascade_ack signal at the same time it copies the relevant cascade data bus fields.
8
DFCIN/OUT_FLUSH
Decimation Filter Cascade Input/Output Flush control bit
The DFCIN/OUT_FLUSH bit indicates to the receiver Decimation Filter block that it should
execute a flush command — thus some internal registers are placed in the initial state.
9-10
DFCIN/OUT_CTRL
[1:0]
Decimation Filter Cascade Input/Output Control bits
The DFCIN/OUT_CTRL[1:0] field has the same function as the M_CTRL[1:0] control bits
described in
Table 26-29 . This field defines the operation to be executed with the
DFCIN/OUT_DATA[15:0] data.
12-15
DFCIN/OUT_TAG
[3:0]
Decimation Filter Cascade Input/Output Tag bits
The DFCIN/OUT_TAG[3:0] field indicates the destination associated with the
DFCIN/OUT_DATA[15:0] data. This value is stored by the Decimation Filter and used to
address the destination register when a decimated sample is available to be read by the
master block.
DFCIN/OUT_DATA
[15:0]
Decimation Filter Cascade Input/Output Data
The DFCIN/OUT_DATA[15:0] bit field carries the data to be transmitted in the chain of
cascaded decimation filter blocks.