Datasheet
Signal
L1_Instr_DF[31:7] 3 6
L2_Instr_DF[31:7] 1 2
L3_Instr_DF[31:7] 2 3
Delay caused by TU load
t1 t2
LRP
Frame
Request
t3
t4
t5 t6 t7
Request
Quiet Request
Quiet Request
Signal
L1_Instr_DF[31:7] 3 6
L2_Instr_DF[31:7] 1 2
L3_Instr_DF[31:7] 2
t1 t2
LRP
Frame
3
Request
t3 t4 t5 t6
Request
LRP
t7
Delay caused by TU load
Quiet Request Quiet Request
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Module Operation
Figure 24-10. Timing which Generates No Request Lost Error
Figure 24-11. Timing which Generates a Request Lost Error
To ensure consistent data, the NHET instructions are able to generate a quiet request, which does not
originate a transfer but is only used by the HTU for consistency check. If a frame has not completed since
the last request (or has not even started) at the time the quiet request occurs, then the HTU signals a
request lost error. All instructions, which allow to generate a request can be configured to generate a quiet
request instead. So in the examples of Figure 24-10 and Figure 24-11, instruction L1 should be configured
to generate a quiet request and instruction L3 to generate a normal request. In the case of Figure 24-11,
the corresponding bit in the RLOSTFL register will be set.
It is the responsibility of the NHET software to enable a quiet request for the first instruction of an
instruction block, which is addressed by DCP x, and to enable a normal request only for the last
instruction of this block. Since enabling the quiet request should enable a proper request lost detection for
DCP x, both NHET instructions need to specify the same DCP x (reqnum=x).
The control fields of the HET instructions provide a 2-bit field to configure one of the following possibilities
(as shown in Table 24-2). A 3-bit field in the program field will select which of the 8 Double Control
Packets will be triggered by the request.
Table 24-2. Triggered Control Packets
Request Type Bit 1 Request Type Bit 0 Request Number
Don't care 0 No request
Specify number 0, 1,... or 7, which selects
0 1 Generate normal request
the HTU or DMA request line
1 1 Generate quiet request
1075
SPNU562–May 2014 High-End Timer Transfer Unit (HTU) Module
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