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High Speed Inter-Chip USB 2.0 Hub and Flash Media Controller
Datasheet
Revision 1.0 (06-01-09) 38 SMSC USB4640/USB4640i
DATASHEET
8.4.2.3 A4h-A5h: Smart Media Device Power Configuration
8.4.2.4 A6h-A7h: Secure Digital Device Power Configuration
8.4.2.5 A8h: LED Blink Interval
8.4.2.6 A9h: LED Blink Duration
FET TYPE BITS BIT TYPE DESCRIPTION
0 FET Lo Byte
SM_PWR_LB
3:0 Low Nibble 0000b Disabled
1 7:4 High Nibble
2 FET Hi Byte
SM_PWR_HB
3:0 Low Nibble 0000b Disabled
0001b External FET enabled
1000b Internal FET with 100 mA power limit
1010b Internal FET with 200 mA power limit
3 7:4 High Nibble 0000b Disabled
FET TYPE BITS BIT TYPE DESCRIPTION
0 FET Lo Byte
SD_PWR_LB
3:0 Low Nibble 0000b Disabled
1 7:4 High Nibble
2 FET Hi Byte
SD_PWR_HB
3:0 Low Nibble 0000b Disabled
0001b External FET enabled
1000b Internal FET with 100 mA power limit
1010b Internal FET with 200 mA power limit
3 7:4 High Nibble 0000b Disabled
BYTE NAME DESCRIPTION
0 LED_BLK_INT The blink rate is programmable in 50 ms intervals. The high bit (7) indicates
an idle state:
‘0’ - Off
‘1’ - On
The remaining bits (6:0) are used to determine the blink interval up to a max
of 128 x 50 ms.
BYTE NAME DESCRIPTION
1 LED_BLK_DUR LED Blink After Access. This byte is used to designate the number of
seconds that the GPIO1 LED will continue to blink after a drive access.
Setting this byte to "05" will cause the GPIO 1 LED to blink for 5 seconds
after a drive access.