Cutting Of Device - Fujitsu MB90335 Series Hardware Manual

CHAPTER 12 USB HOST
12.5 Operation of USB HOST
12.5.11

Cutting of Device

Once both HOST pins D + and D- become "L", the disconnection timer starts, and sets
the CSTAT bit of the host state status register (HSTATE) to "0" when both pins detect
"L" for 2.5 μs or longer.
■ Cutting of Device
Regardless of Host mode and function mode, when both Host pins D+ and D- detect "L" for 2.5 μs or
longer, it determines that the device is cut. Therefore, the CSTAT bit of the host state status register
(HSTATE) becomes "0", and the DIRQ bit of the host interrupt register (HIRQ) is set to "1". If the DIRE
bit of the host control register 0(HCNT0) is "1", an interrupt generates. To clear the interrupt, write "0" to
the DIRQ bit of the HIRQ.
When a reset is performed on the USB bus, it determines that the device is disconnected and sets the
CSTAT bit of the host state status register 0 (HSTATE) to "0", but the DIRQ bit of the host interrupt
register (HIRQ) does not become "1".
286 FUJITSU MICROELECTRONICS LIMITED
MB90335 Series
CM44-10137-6E