isp1504a NXP Semiconductors, isp1504a Datasheet - Page 42

• Manufacturer Part Number: isp1504a
• Description: Ulpi Hi-speed Universal Serial Bus On-the-go Transceiver
• Manufacturer: NXP Semiconductors

NXP Semiconductors
ISP1504A_ISP1504C_3
Product data sheet
9.10.3 Remote wake-up
The ISP1504 supports peripherals that initiate remote wake-up resume. When placed into
USB suspend, the peripheral link remembers at what speed it was originally operating.
Depending on the original speed, the link follows one of the protocols detailed here. In
Figure
The sequence of events related to a host and a peripheral, both with ISP1504, is as
follows:
1. Both the host and the peripheral are assumed to be in low-power mode.
2. The peripheral begins remote wake-up by re-enabling its clock and setting its
3. The peripheral begins driving K on the bus to signal resume. Note that the peripheral
4. The host recognizes the resume, re-enables its clock and sets its SUSPENDM bit.
5. The host takes over resume driving within 1 ms of detecting the remote wake-up.
6. The peripheral stops driving resume.
7. The peripheral sees the host continuing to drive resume.
8. The host stops driving resume and the ISP1504 automatically adds the EOP to the
9. Both the host and the peripheral revert to normal operation by writing 00b to
SUSPENDM bit to 1b.
link must assume that LINESTATE is K (01b) while transmitting because it will not
receive any RXCMDs.
end of resume. The peripheral recognizes the EOP as the end of resume.
OPMODE. If the host or the peripheral was previously in high-speed mode, it must
revert to high-speed before the SE0 of the EOP is completed. This can be achieved
by writing XCVRSELECT[1:0] = 00b and TERMSELECT = 0b after LINESTATE
indicates SE0.
20, timing is not to scale, and not all RXCMD LINESTATE updates are shown.
Rev. 03 — 7 April 2008
ISP1504A; ISP1504C
ULPI HS USB OTG transceiver
© NXP B.V. 2008. All rights reserved.
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