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Four data sources can be selected for each SRL bit by using several control bits and one
control signal:
•
ALTINL input line (non-inverted)
•
ALTINL input line (inverted)
•
Bit of DD.DDL (downstream data register)
•
Bit of DC.DCL (downstream control register)
When SRL is loaded for data frame transmission (DSC.CP = 0), bit fields DSDSL.SLx
determine bit-wise which data is loaded into SRL bit x. The data source selection as
controlled by DSDSL.SLx will only be effective when EMGSTOPMSC is inactive (at low
level). When EMGSTOPMSC = 1 (active) during the load operation, all SRL[x] bits that
are enabled for the emergency stop feature (bit ESR.ENLx = 1) are loaded directly with
the corresponding bit DDL[x] of the downstream data register DD.
When SRL is loaded for command frame transmission (DSC.CP = 1), always the lower
16-bit part DCL of the downstream control register is loaded completely into SRL.
Table 19-5
summarizes all SRL data source selection capabilities (x = 0-15).
Table 19-5
SRL Data Source Selection Capabilities
DSC.
DSDSL.
ESR.
CP
SLx
ENLx
0
00
0
B
01
B
10
B
11
B
XX
1
B
1
XX
X
B
SRH Shift Register Loading
The SRH shift register load operation is equivalent to the SRL shift register load
operation. The following differences must be taken into account for SRH shift register
loading:
•
Input lines ALTINH are connected instead of ALTINL input lines.
•
DSDSH register bits control data source selection instead of DSDSL register.
•
Emergency stop is enabled by ESR.ENHx bits instead of ESR.ENLx bits.
•
Bits of the downstream data register high part DDH are selected instead of DDL.
•
Downstream control register high part DCH is selected instead of DCL.
User's Manual
MSC, V1.37 2009-05
EMGSTOPMSC
–
1
X
19-13
Micro Second Channel (MSC)
Selection
Bit DD.DDL[x] is loaded into SRL[x].
Reserved.
State of ALTINL[x] input is loaded into
SRL[x].
Inverted state of ALTINL[x] input is loaded
into SRL[x].
Bit DD.DDL[x] is loaded into SRL[x].
Bit fields DCL and DCH are completely
loaded into SRL and SRH, respectively.
TC1728
V1.0, 2011-12
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