MA28139 Datasheet, PDF (13/34 Pages) Dynex Semiconductor – OBDH Bus Terminal

MA28139
RTU KERNEL PROTOCOL VIOLATIONS
Some commands to the RTU Kernel cannot be completed
within one Interrogation period (or “slot”) because of the need
to provide a slow external interface as defined in ESA standard
TTC-B-01. These are commands for 16-bit Digital Serial
Acquisition (S16) and 16-bit Memory Load (ML). In addition, it
is also possible to inhibit On/Off commands by pin
configuration.
Consequently:
s a Memory Load command cannot be followed by another
Memory Load command in the next Interrogation; the
second command of such a sequence will be ignored,
s a 16-bit Digital Serial Acquisition (S16) cannot be
followed by another acquisition or command in the next
Interrogation; the second command of such a sequence
will be ignored,
s a Long On/Off command will be ignored if the On/Off
command Inhibit input pin, OOINH, is high.
Note that in all MODE Dependent Command and
Acquisition Interrogations, bits 23 to 30 of the Interrogation are
output as an 8 bit channel address on CHADD(0:7). ESA
standard TTC-B-01, p.110 specifies a 7 bit channel address in
bits 27 to 29, leaving bit 30 as Reserved. For complete
compliance with this standard, CHADD(7) should be
disregarded and CHADD(0:6) only should be used.
The signals generated by the RTU Kernel during 8-bit
Single-Ended and 8-bit Double-Ended Analog Data
Acquisitions are intended for connection to an 8-bit serial ADC
module. The outputs PC, ANCLK, SOC and SH are intended
to provide ADC power control, conversion clock, start of
conversion pulse and sample/hold control respectively.
RTU Kernel BroadCast Pulse and BCP Validity Waveforms
are shown in Figure 12.
RTU Kernel Memory Load Command Waveforms are
shown in Figure 13.
RTU Kernel MODE Dependent Command and Acquisition
Waveforms are shown in Figures 14 - 17.
RTU KERNEL MODE DEFINITIONS
The mode field contained in bits 19 to 22 of the
Interrogation is decoded during acquisition commands to drive
one of the MOSC, MOLC, MOHL, MOBT, MODBL, MODS8,
MODS16, MOANS or MOAND outputs. Mode decoding is an
extension of that defined in ESA standard TTC-B-01 Table 7.1
and is shown in Table 1 below:
Bit 19
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Mode Code
Bit 20 Bit 21
0
0
0
0
0
1
0
1
1
0
1
0
1
1
1
1
0
0
0
0
0
1
0
1
1
0
1
0
1
1
1
1
Bit 22
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Function
Unused
Short Switch Closure On/Off Command
Long Switch Closure On/Off Command
High Power Switch Closure On/Off Cmd
Unused
Unused
Unused
Block Transfer Command
8-bit Digital Bi-Level Data Acquisition
Unused
16-bit Serial Digital Data Acquisition
8-bit Serial Digital Data Acquisition
8-bit Single-Ended Analog Data Acquisition
Unused
8-bit Double-Ended Analog Data Acquisition
Unused
Table 1: RTU Kernel Mode Definitions
Associated
Output Pin
-
MOSC
MOLC
MOHL
-
-
-
MOBT
MODBL
-
MODS16
MODS8
MOANS
-
MOAND
-
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