MSC8144E Reference Manual, Rev. 3
16-176
Freescale
Semiconductor
Serial RapidIO
®
Controller
16.6.67
Outbound Message x Descriptor Queue Enqueue Pointer Address
Registers (OMxDQEPAR)
OMxDQEPAR
contains the address for the next descriptor in memory to be added to the queue.
Software must initialize this register to match the outbound message descriptor queue dequeue
pointer address. When a message is ready to be sent, the processor writes a descriptor to the next
location in the queue (indicated by the address in OMxDQEPAR ), and then either writes the
OMxDQEPAR to point to the next descriptor location in memory or sets OMxMR[MUI]. This
can result in a number of actions:
If the enqueue and dequeue pointers match, the queue is now full. If the OMxMR[QFIE]
bit is set, then the OMxSR[QFI] bit is set, and an interrupt is generated.
If the enqueue and dequeue pointers no longer match after the enqueue pointer is
incremented and the queue is full, then the queue overflows, and the message unit stops. If
OMxMR[QOIE] is set, then the controller sets OMxSR[QOI] and generates an interrupt.
OMxMR[MUS] must change from a 1 to a 0 to clear this error condition. If the enqueue
pointer is written directly, the queue overflow condition is not detected.
If the enqueue and dequeue pointers were the same before the register is incremented, the
message unit controller will start, if enabled.
Note:
When software initializes these registers, they must be aligned on a boundary equal to
the number of queue entries
×
32 bytes (the size of each queue descriptor). For
example, if there are eight entries in the queue, the register must be 256-byte aligned.
The number of queue entries is set in OMxMR[CIRQ_SIZ].
OM
[0–1]
DQEPAR
Outbound Message x Descriptor
Offset 0 x*0x100
Queue Enqueue Pointer Address Registers
Bit
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
DQEPA
TYPE
R/W
RESET
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Bit
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DQEPA
—
TYPE
R/W
R
RESET
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 16-110. OMxDQEPAR Field Descriptions
Bits
Reset Description
DQEPA
31–5
0
Descriptor Enqueue Pointer Address
Contains the address of the next free descriptor location. The descriptor must be aligned to a
32-byte boundary and a descriptor queue boundary.
—
4–0
0
Reserved. Write to zero for future compatibility.
Summary of Contents for MSC8144E
Page 1: ...MSC8144E Reference Manual Quad Core Media Signal Processor MSC8144ERM Rev 3 July 2009 ...
Page 48: ...MSC8144E Reference Manual Rev 3 xlviii Freescale Semiconductor ...
Page 86: ...MSC8144E Reference Manual Rev 3 1 38 Freescale Semiconductor Overview ...
Page 168: ...MSC8144E Reference Manual Rev 3 3 60 Freescale Semiconductor External Signals ...
Page 242: ...MSC8144E Reference Manual Rev 3 5 26 Freescale Semiconductor Reset ...
Page 314: ...MSC8144E Reference Manual Rev 3 8 24 Freescale Semiconductor General Configuration Registers ...
Page 414: ...MSC8144E Reference Manual Rev 3 10 14 Freescale Semiconductor MSC8144E SC3400 DSP Subsystem ...
Page 452: ...MSC8144E Reference Manual Rev 3 11 38 Freescale Semiconductor Internal Memory Subsystem ...
Page 520: ...MSC8144E Reference Manual Rev 3 12 68 Freescale Semiconductor DDR SDRAM Memory Controller ...
Page 1070: ...MSC8144E Reference Manual Rev 3 21 28 Freescale Semiconductor Timers ...