ISD-200 Datasheet, PDF (40/64 Pages) List of Unclassifed Manufacturers – USB Mass Storage Class Bulk-Only Specification Compliant

ISD-200 ASIC Datasheet
If an event notification command does not complete for any reason (such as an incoming reset), the ISD-
200 will re-issue the command (with any new event data) until it completes successfully. Success of the
command does NOT depend upon the ERR bit. If the DRQ bit is set in response to an event notification,
ISD-200 will continue to poll (in order to make device incompatibility obvious).
Power Management
BUS_POWER Pin
First silicon does not support the BUS_POWER pin being set (See Errata #6). The ISD-200 reacts to the
following conditions as stated:
• When a USB suspend condition exists and BUS_POWER pin is asserted, the external clock
source(CLKN) is disabled, and if remote wakeup is disabled the oscillator is turned off, all ATA
outputs put into low power mode, and ATA control lines (nATA_RESET, nDIOR, nDIOW) are 3-
stated to hi-Z.
• When a USB suspend condition exists the remainder of the ATA lines (nCS(1:0), DA(2:0),
DD(15:0)) are driven low. First silicon Errata #6 includes all ATA lines being three-stated only
when BUS_POWER is asserted, and a suspend condition exists.
• When the BUS_POWER pin is asserted, the USB Configuration value is set to zero, and
configuration byte 8 bit 4 is set, all ATA outputs are put into low power mode, ATA control lines
(nATA_RESET, nDIOR, nDIOW) are 3-stated to hi-Z.
• When the USB Configuration value is set to zero, and configuration byte 8 bit 4 is set the
remainder of the ATA lines (nCS(1:0), DA(2:0), DD(15:0)) are driven low. First silicon does not
support this feature (See Errata #6).
• The ISD-200 resets itself in the following cases:
o If BUS_POWER is asserted USB configuration is set to 2.
o If BUS_POWER changes when the USB configuration is set to 0.
• The ISD-200 drives USB_ENUM before attempting to talk to attached device.
• The ISD-200 does not attempt to talk to the disk until the USB configuration is set to either 1 or 2.
First silicon does not support this feature (See Errata #6).
• Setting the Descriptor Override bit is incompatible with setting BUS_POWER pin.
The assertion of BUS_POWER will cause a Get Status USB request from the host to report a ‘0’
(indicating bus-powered status) in bit 0 of the information returned. The de-assertion of BUS_POWER
will cause a Get Status USB request from the host to report a ‘1’ (indicating self-powered status) in bit 0 of
the information returned.
BUS_POWER pin state may also effect how USB descriptors are presented to the host (See Selectable
Device Power Configurations section below). (See Errata #6)
NPWR500, and NPWR100 Pins
The NPWR500 and NPWR100 output pins indicate that the USB host has allotted the requested
power(bMaxPower) to the peripheral system (See Figure 5). These pins allow USB power to be controlled
in order to meet USB power consumption requirements. In the case of a USB Suspend condition, both
NPWR500 and NPWR100 are de-asserted. Also, the ISD-200 will put itself into a low power state as
described above. Upon a resume condition, the ISD-200 will resume normal operation and restore the
NPWR500 and NPWR100 pin values as before suspend. ISD-200’s power source is not to be controlled at
any time using the NPWR500 or NPWR100 pins.
NPWR100 is always asserted unless in USB suspend. NPWR100 asserted indicates that up to 100 mA may
be drawn from USB. NPWR500 is only asserted when the USB configuration is set to 1.
NPWR500 asserted indicated that up to 500 mA may be drawn from USB depending on what the
bMaxPower value is set to for configuration 1
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