MA28140 Datasheet, PDF (34/72 Pages) Dynex Semiconductor – Packet Telecommand Decoder

MA28140
When CPDUS is asserted, the pointer for reading out data
with FAR1S is reset to the first octet of the FAR. The samples
CPDUS and FAR1S should be activated as described in
Figure 16 to fetch the 128 bits of status words. The first 16 bits
are those of the CPDU status word, to be acquired by asserting
the CPDUS signal line. The next 32 bits are those of the FAR
status word, to be acquired by signalling on the FAR1S signal
line (2 x 16 bits). The last 80 bits are those of the AU status
word, to be acquired by additional assertions (5 x 16 bits) of the
FAR1S signal line. It is possible to read out only the first 48 bits
(CPDU and FAR), e.g. if the AU is not used.
FAR1S, AU1S and AU2S do not have any impact in this
mode, but should be connected to V_DD.
5.4 PARALLEL INTERFACE
A parallel interface is provided on the PTD to access the
TC segment and the four reporting words: CLCW, CPDUS,
FAR and AUS. The parallel mode is selected with the PAR
configuration pin of the PTD (the parallel mode is selected
when PAR is set to 1). The parallel interface is implemented
with the following signals:
• PCSN: parallel bus chip select input,
• PAD<2..0>: parallel address bus (input),
• PRDY: data validation output,
• PBUS<15..0>: parallel data bus (output),
• MAPDSR: MAP data set ready output,
• MAPADT: MAP aborted data transfer output.
The PCSN, PAD2, PAD1 and PAD0 signal lines use
respectively the CPDUS, FAR1S, FAR2S and AU1S input pins
of the serial interface. The application acquires the TC
segment and the four reporting words by read cycles. The
addressing of these words is as follows:
PAD2
0
0
0
0
1
1
1
1
PAD1
0
0
1
1
0
0
1
1
PAD0
0
1
0
1
0
1
0
1
read word
MAP segment
CPDU status
CLCW status
MAP status
FAR1 status
FAR2 status
AU1 status
AU2 status
When the AU1 status is read, the pointer for reading out
data with AU2S is reset. The MAP TC segment is read as
described in Figure 17.
A TC segment is read by consecutive accesses to <000>.
Data read when MAPDSR is not asserted is not valid. The TC
segment data octet of even rank is output on the 8 MSB of
PBUS (the first octet is 00 and therefore even). The TC
segment data octet of odd rank is output on the 8 LSB of
PBUS. In the case of a TC segment with an odd number of
octets, the last 16 bits word output on PBUS contains the last
TC segment data octet on the 8 MSB and a non significant
octet (all bits set to 0) on the 8 LSB. For example, if the TC
segment to be output is (hexadecimal) AABBCC, the first word
read is AABB and the second one is CC00.
After a PCSN assertion, the PRDY output is activated
when the data is available on the PBUS output. The PRDY is
released when the PCSN signal is deasserted. The PRDY
signal will not be asserted if PCSN is asserted and PAD = 000
(MAP segment read) when MAPDSR is inactive. When PCSN
is deasserted the PBUS bus is tristated. The MAP status word
can be read at any time. The access to this word is identical to
the telemetry status word accesses as described in Figure 18.
It contains the following information:
• PBUS<0>: MAPDSR information (identical to MAP data
set ready signal line).
• PBUS<1>: ODD/EVEN segment length information
(Odd: 1, Even: 0).
• PBUS<15..2>: not used (value : 00000000000000).
NOTE: only TC segments appearing on MAP 1 to 62 and
on MAP 63 when AU is disabled, can be read out using this
parallel interface. MAP 0 is not affected by this parallel
interface since it is directly connected to the CPDU. The
telemetry status word is read as described in Figure 18.
The CLCW status word is read using one read cycle where
PAD = 010.
The CPDU status word is read using one read cycle where
PAD = 001.
The FAR status words are read with two read cycles:
• One read cycle with PAD = 100 for the first 16 bits
(FAR1)
• One read cycle with PAD = 101 for the last 16 bits
(FAR2).
The AU status words are read using five read cycles:
• One read cycle with PAD = 110 for the first 16 bits (AU1)
• Four read cycles with PAD = 111 for the last 64 bits
(AU2): bits 16-31, bits 32-47, bits 48-63 and bits
64-79.
When the AU1 Status report is read, the pointer for reading
out data with AU2 is reset to the second octet of the AU report.
The Status of Survey bit is set when FAR2 is read. The
following pins have no influence in parallel mode:
• MAPDTR (should be connected to V_SS),
• CLCWSA, CLCWCA (should be connected to V_DD),
• AU2S (should be connected to V_DD),
• TMC (should be connected to V_DD),
• TMMOD (should be connected to V_SS),
The reports and TC segments cannot be read out in an
arbitrary order. The following constraints apply: A FAR2 read
out shall not be separated from the previous FAR1 read out by
AU1 or AU2 read out. An AU2 read out shall not be separated
from a previous AU1 or a previous AU2 read out by FAR1 or
FAR2 read out.
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