PRELIMINARY
CM2400-05
Functional Description (cont’d)
Detailed in Table 4 is the differential result for all varia-
Detection of a V
voltage is accomplished via an
BUS
tions on V /V and V /V .
internal Comparator with hysteresis. The output from
this Comparator is fed via the level translator to ensure
compatibility with processor core voltages and output
P
PO
M
MO
VP/VPO
VM/VMO
Result
Logic ‘0’
SE0
to pin USB_DET. When V
is over 4.1 volts
BUS
USB_DET is HIGH. When V
USB_DET is LOW.
is under 3.6 volts
L
L
L
H
L
BUS
H
H
Logic ‘1’
SE0
H
The CM2400-05 USB transceiver includes an enumer-
ation pin (ENUM) which internally connects V to
Table 4: Operating Mode (OE = L)
PU
V
when enabled. This allows a processor running
REG
Table 5 details the receiving function when OE is HIGH
(driver disabled). RCV denotes the signal level on the
output RCV just before an SE0 state occurs. This level
is stable during the SE0 period.
at a core voltage different than 3.3V to switch the pull-
up resistor in and out without the need for external cir-
cuitry.
VP
VM
D+/D-
RCV
L
Differential Logic ’0’
Differential Logic ’1’
SE0
L
H
L
H
L
L
H
RCV*
Table 5: Receiving Function (SPND = L)
Note 1: Denotes RCV is stable in last state before
SE0 condition.
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