ISP1507DBSUM STEricsson, ISP1507DBSUM Datasheet - Page 33

• Manufacturer Part Number: ISP1507DBSUM
• Manufacturer: STEricsson

Specifications of ISP1507DBSUM

• Lead Free Status / RoHS Status: Compliant

CD00222690
Product data sheet
9.10.1 Full-speed and low-speed host-initiated suspend and resume
9.10 USB suspend and resume
preamble mode, the ISP1507 operates just as in full-speed mode, and sends all data with
the full-speed rise time and fall time. Whenever the link transmits a USB packet in
preamble mode, the ISP1507 will automatically send a preamble header at full-speed bit
rate before sending the link packet at low-speed bit rate. The ISP1507 will ensure a
minimum gap of four full-speed bit times between the last bit of the full-speed PRE PID
and the first bit of the low-speed packet SYNC. The ISP1507 will drive a J for at least one
full-speed bit time after sending the PRE PID, after which the pull-up resistor can hold the
J state on the bus. An example transmit packet is shown in
In preamble mode, the ISP1507 can also receive low-speed packets from the full-speed
bus.
Figure 14
suspend and sometime later initiates resume signaling to wake up the downstream
peripheral. Note that
LINESTATE updates.
The sequence of events for a host and a peripheral, both with ISP1507, is as follows:
1. Idle: Initially, the host and the peripheral are idle. The host has its 15 kΩ pull-down
2. Suspend: When the peripheral sees no bus activity for 3 ms, it enters the suspend
Fig 13. Preamble sequence
DATA[7:0]
resistors enabled (DP_PULLDOWN and DM_PULLDOWN are set to 1b) and 45 Ω
terminations disabled (TERMSELECT is set to 1b). The peripheral has the 1.5 kΩ
pull-up resistor connected to DP for full-speed or DM for low-speed (TERMSELECT is
set to 1b).
state. The peripheral link places the PHY into low-power mode by clearing the
SUSPENDM bit in the FUNC_CTRL register (see
draw only suspend current. The host may or may not be powered down.
DP or DM
CLOCK
NXT
STP
DIR
DP and DM timing is not to scale.
illustrates how a host or a hub places a full-speed or low-speed peripheral into
Figure 14
FS SYNC
Rev. 04 — 20 May 2010
TXCMD (low-speed packet ID)
timing is not to scale, and does not show all RXCMD
PRE ID
FS
IDLE (min
4 FS bits)
ULPI HS USB host and peripheral transceiver
ISP1507C; ISP1507D
LS SYNC
Section
D0
LS PID
Figure
10.1.2), causing the PHY to
D1
LS D0
13.
© ST-ERICSSON 2010. All rights reserved.
LS D1
004aaa714
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