Datasheet

DOUT/MB0
In MODBIT mode, the DOUT/MB0 outputs the real-time
modulator data (MB0). When the ENMSYNC bit = 0, DOUT/
MB0 outputs the first MSYNC pulse and shifts out the
even bits of the modulator data (bit 4, bit 2, and bit 0). The
first SYNC pulse (indicating valid modulator data) will be
shifted out on the positive clock edge (referred to as clock
edge 1) for initial synchronization. For all other data cycles,
the clock edge 1 will output 0 on this pin (as well as 0 on
GPIO1/MB1) indicating the end of a current data stream.
On clock edge 2, 3, and 4 DOUT/MB0 shifts out the even
data bits as described earlier.
GPIO3/MSYNC
When ENMSYNC = 1 in the MODBIT mode, GPIO3/
MSYNC functions as the modulator sync (MSYNC) out-
put. The SYNC pulse from the modulator is shifted out on
the positive clock edge. When the sync signal shifts out
on the GPIO3/MSYNC pin, the data is “00” on both the
DOUT/MB0 and GPIO1/MB1 pins and marks the starting
point of the next modulator data.
GPIO1/MB1
In MODBIT mode, the GPIO1/MB1 functions as a real-
time modulator data output. On clock edge 1, GPIO1/MB1
always outputs 0 (irrespective of the state of ENMSYNC).
On clock edge 2 and 3, this pin will shift out the odd bits
of the modulator data (bit 3 and bit 1). GPIO1/MB1 is 0 on
clock edge 3 as well.
RDYB/ICLK
When the MODBITS bit = 1, the internal system clock
(running at 8.192MHz) is output on RDYB/ICLK. This
enables aligning the data to the clock edge.
The description of the data shift described above is
detailed in the Figure 13. It shows both cases with
ENMSYNC = 0 or 1 and the difference in the behavior of
GPIO3/MSYNC and DOUT/MB0. RDYB and GPIO1/MB1
are unaffected by the ENMSYNC bit.
Table 11. MODBITS Mode Pins
NORMAL FUNCTION MODBITS FUNCTION DESCRIPTION
DOUT MB0
ENMSYNC=0, output MSYNC rst followed by even bits of
modulator data. ENMSYNC=1, output even bits of modulator data
only
GPIO1 MB1 Odd bits (bits 1 and 3) of modulator data
GPIO3 MSYNC Shifts SYNC pulses from the modulator
RDYB ICLK Internal clock
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