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Philips Semiconductors
ISP1122
USB stand-alone hub
Product specification Rev. 03 — 29 March 2000 5 of 48
9397 750 07002
© Philips Electronics N.V. 2000. All rights reserved.
[1] Symbol names with an overscore (e.g. NAME) indicate active LOW signals.
[2] The voltage at pin V
reg(3.3)
is gated by the RESET pin. This allows fully self-powered operation by
connecting RESET to V
BUS
(+5 V USB supply). If V
BUS
is lost upstream port D+ will not be driven.
[3] See Table 4 “Mode selection”.
[4] To disable a downstream port connect both D+ and D− to V
CC
via a 1 MΩ resistor; unused ports must
be disabled in reverse order starting from port 5.
[5] Analog detection circuit can be switched off using an external EEPROM, see Table 23; in this case,
the pin functions as a logic input (TTL level).
[6] Downstream ports 1 and 2 cannot be disabled.
DP1 27 AI/O downstream port 1 D+ connection (analog)
[6]
DM0 28 AI/O upstream port D− connection (analog)
DP0 29 AI/O upstream port D+ connection (analog)
DM2 30 AI/O downstream port 2 D− connection (analog)
[6]
DP2 31 AI/O downstream port 2 D+ connection (analog)
[6]
PSW1/GL1
[3]
32 O modes 4 to 6: power switch control output for downstream
port 1 (open-drain, 6 mA)
modes 0 to 3, 7: GoodLink LED indicator output for
downstream port 1 (open-drain, 6 mA); to connect an LED
use a 330 Ω series resistor
Table 2: Pin description for SO32 and SDIP32
…continued
Symbol
[1]
Pin Type Description