CS5376
No delay occurs between receiving the MFLAG
signal from the modulators and being output in the
SD port status word. Depending on the group delay
of the digital filters, the invalid data from the mod-
ulator will not be output for several conversion
words after receiving the MFLAG signal. Also, af-
ter recovery of the modulator and clearing of the
MFLAG signal, some number of conversion words
are required before the digital filter will again out-
put valid data.
See “Modulator Data Interface” on page 49 for
more information about the MFLAG signal from
the modulators.
Channel Number Bits - CH[1:0]
The channel number bits indicate which conversion
channel the data word is from. One CS5376 can fil-
ter data for up to four modulators, the channel num-
ber field encodes which modulator the current data
word is from. Note that the channel number,
CH[1:0], is zero based.
• CH[1:0] = 00 = Channel 1
• CH[1:0] = 01 = Channel 2
• CH[1:0] = 10 = Channel 3
• CH[1:0] = 11 = Channel 4
Time Break Flag - TB
The time break flag marks a timing reference in the
output data stream. When a rising edge is received
on the TIMEB pin a time break event is initiated.
The decimation engine writes the TB flag in the
status byte of the SD port output after a delay pro-
grammed in the TIMEBRK register (0x29). The
TB flag is set in one output word for all enabled
conversion channels. See “Time Break Function”
on page 75 for more information about how the
time break function is used as a timing reference.
Port Overflow Flag - W
The port overflow flag indicates an overflow con-
dition in the SD port data FIFO, and is set by hard-
ware when the decimation engine overwrites a
FIFO register whose data has not been sent. The W
flag is independently set for each output word and
channel.
Conversion Data Word
The last 24 bits of the SD port output word is the
conversion data for the specified channel. The con-
version data is a 24-bit two’s complement value.
See “Digital Decimation Filter” on page 53 for
more information how conversion data is generated
in the digital filters.
DS256PP1
74