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CHAPTER 6 USB CONTROLLER
390
Preliminary User’s Manual S14767EJ1V0UM00
6.2.2.14
USB Command Register (U_CMR): 40H
31
B
16
15
Command
0
Data Size/NOD
30
27
26
24
23
Reserved
Reserved
Register for adding data segment send or receive Buffer Directories.
The V
R
4120A RISC Processor writes commands into this register.
Whenever B bit (Bit 31) is set, even if V
R
4120A RISC Processor writes commands into this register, the value will
not change.
Bit
Field
Description
R/W
31
B
(Busy)
Bit that indicates whether the interpretation of an issued command has
terminated. When the execution of the command has not yet terminated,
this bit will be set to 1. When the execution of a command has terminated,
this bit will be set to 0.
When the V
R
4120A RISC Processor issues one command immediately after
another, it is necessary to confirm that this bit is set to 0.
R
30-27
Reserved
Reserved for future use
R/W
26-24
Command
Field for specifying the type of a command. USB Controller's internal
processing varies depending on the value written into this field.
000: Data sending at EndPoint0
001: Data sending at EndPoint1
010: Data sending at EndPoint3
011: Data sending at EndPoint5
100: Addition of Buffer Directories to Pool0
101: Addition of Buffer Directories to Pool1
110: Addition of Buffer Directories to Pool2
111: Reserved (Don't Use)
R/W
23-16
Reserved
Reserved for future use
R
15-0
Data Size/NOD
(Data Size / Number Of
Buffer Directory)
The meaning of this field depends on the value written into the EPN field.
EPN=0xx: This field has no meaning.
EPN=100,101,110: Indicates the number of Buffer Directories added to a
pool.
EPN=111: This field has no meaning.
R/W