isp1504c NXP Semiconductors, isp1504c Datasheet - Page 9

• Manufacturer Part Number: isp1504c
• Description: Ulpi Hi-speed Universal Serial Bus On-the-go Transceiver
• Manufacturer: NXP Semiconductors

NXP Semiconductors
ISP1504A_ISP1504C_1
Product data sheet
7.6.2.1 V
7.6.2.2 Session valid comparator
7.6.2.3 Session end comparator
7.6.1 ID detector
7.6.2 V
7.6.3 SRP charge and discharge resistors
The ID detector detects which end of the mini-USB cable is plugged in. The detector must
first be enabled by setting the ID_PULLUP register bit to logic 1. If the ISP1504 senses a
value on ID that is different from the previously reported value, an RXCMD status update
will be sent to the USB link, or an interrupt will be asserted.
The ISP1504 provides three comparators, V
comparator and session end comparator, to detect the V
This comparator is used by hosts and A-devices to determine whether the voltage on
V
comparator is V
During power-up, it is expected that the comparator output will be ignored.
The session valid comparator is a TTL-level input that determines when V
enough for a session to start. Peripherals, A-devices and B-devices use this comparator to
detect when a session is started. The A-device also uses this comparator to determine
when a session is completed. The session valid threshold of the ISP1504 is V
with a hysteresis of V
The ISP1504 session end comparator determines when V
session end threshold. The B-device uses this threshold to determine when a session has
ended. The session end threshold of the ISP1504 is V
The ISP1504 provides on-chip resistors for short-term charging and discharging of V
These are used by the B-device to request a session, prompting the A-device to restore
the V
previous session by setting the DISCHRG_VBUS register bit to logic 1 and waiting for
SESS_END to be logic 1. Then the B-device charges V
register bit to logic 1. The A-device sees that V
threshold and starts a session by turning on the V
•
•
•
•
•
BUS
BUS
BUS
V
detection, SRP and HNP.
Resistors to temporarily charge and discharge V
Charge pump to provide 5 V power on V
power from the ISP1504 V
If the mini-B end of the cable is plugged in, the ISP1504 will report that ID_GND is
logic 1. The USB link must change to peripheral mode.
If the mini-A end of the cable is plugged in, the ISP1504 will report that ID_GND is
logic 0. The USB link must change to host mode.
BUS
BUS
valid comparator
is at a valid level for operation. The ISP1504 minimum threshold for the V
comparators
power. First, the B-device makes sure that V
comparators to determine the V
A_VBUS_VLD
hys(B_SESS_VLD)
Rev. 01 — 19 October 2006
. Any voltage on V
BUS
.
.
BUS
BUS
BUS
BUS
ISP1504A; ISP1504C
voltage level. This is required for the V
BUS
. The downstream peripheral can draw its
valid comparator, session valid
below V
BUS
is charged above the session valid
BUS
BUS
power.
B_SESS_END
BUS
. This is required for SRP.
BUS
A_VBUS_VLD
ULPI HS USB OTG transceiver
is fully discharged from the
BUS
by setting the CHRG_VBUS
voltage level.
is below the B-device
.
is considered a fault.
© NXP B.V. 2006. All rights reserved.
BUS
B_SESS_VLD
is high
BUS
valid
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BUS
BUS
.
,