HTU Control Registers
985
SPNU503C – March 2018
Copyright © 2018, Texas Instruments Incorporated
High-End Timer Transfer Unit (HTU) Module
21.4.3 Control Packet (CP) Busy Register 0 (HTU BUSY0)
This register displays the status of individual control packets.
Figure 21-16. Control Packet (CP) Busy Register 0 (HTU BUSY0) [offset = 08h]
31
25
24
23
17
16
Reserved
BUSY0A
Reserved
BUSY0B
R-0
R/W1CP-0
R-0
R/W1CP-0
15
9
8
7
1
0
Reserved
BUSY1A
Reserved
BUSY1B
R-0
R/W1CP-0
R-0
R/W1CP-0
LEGEND: R/W = Read/Write; R = Read only; W1CP = Write 1 in privilege mode only to clear the bit; -
n
= value after reset
Table 21-15. Control Packet (CP) Busy Register 0 (HTU BUSY0) Field Descriptions
Bit
Field
Value
Description
31-25
Reserved
0
Reads return 0. Writes have no effect.
24
BUSY0A
Busy Flag for CP A of DCP 0
23-17
Reserved
0
Reads return 0. Writes have no effect.
16
BUSY0B
Busy Flag for CP B of DCP 0
15-9
Reserved
0
Reads return 0. Writes have no effect.
8
BUSY1A
Busy Flag for CP A of DCP 1
7-1
Reserved
0
Reads return 0. Writes have no effect.
0
BUSY1B
Busy Flag for CP B of DCP 1
The bit is
set
when the frame on the according control packet
starts
(as shown in the diagram below,
there could be a delay between the request and the start of the frame).
The bit is automatically
cleared
at any of the following conditions:
1. At the end of a frame.
2. Writing a 1 to a BUSY bit (of DCP x) if that bit is 1. This will:
a. clear the element counter of DCP x
b. stop all new element transfers on DCP x
c. clear the busy bit
d. and disable DCP x in the CPENA register.
There is no effect, if the BUSY bit is 0.
3. At the conditions listed in
.
A write access to the CPENA register can stop a control packet (CP) in single buffer mode or it can switch
to the other CP of a DCP in dual buffer mode. If stopping or switching occurs while a frame runs on the
currently active control packet, the CPU can poll the busy bit to determine when it is safe to read the
buffer.