Renesas USB Device
USB Host Mass Storage Class Driver(HMSC)
R01AN0513EJ0110 Rev.1.10
Page 41 of 55
Aug 10, 2011
7.8 Drive
Management
HMSDD sets USBC_DRIVE as the initial drive number of the connected storage device. HMSDD also supports
connection of storage devices with multiple units and multiple drives. It is only necessary to specify the drive number
from the application to access the relevant partition block of any unit. A storage device may have up to four units, and
each unit may have up to 10 partition blocks. The unit count and partition block count can be changed by specifying
new values in the header file.
For example, the drives are managed as shown below when USBC_DRIVE is set to 1, the USB storage device has three
units, unit 0 has three partitions (total of three partitions including extensions), unit 1 has no media, and unit 2 has two
partitions.
Table 7.23 Drive Numbers
Unit Partition Drive
Remarks
0 0
1
(B) FAT32
0
1
Not classified (no drive)
0
2
Extended partition (continuous information read)
0
2 to 0
2 (C)
FAT32 (continuous information of partition 2)
0
2 to 0
Not classified (no drive)
0 3
3
(D) FAT32
1
No
media
2 0
4
(E) FAT16
2 1
5
(F) FAT16
Drive B : \>
Drive D : \>
Drive C : \>
Unit 0
Partition 0
Unit 0
Partition 1 (not classified)
Unit 0
Partition 2 (extension)
Unit 0
Partition 3
Unit 1
No media
Unit 2
Partition 0
Unit 3
Partition 1
Drive E : \>
Drive F : \>
Unit 0 (extension)
Partition 0
Unit 0 (extension)
Partition (not classified)
Figure 7.1 Drive Management
Содержание R8A66597
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