LPC47B272QFP Ver la hoja de datos (PDF) - SMSC -> Microchip
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LPC47B272QFP Datasheet PDF : 195 Pages
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Setup
Warning: Ensure power supply is off during setup.
1. Connect VSS (pins 7, 31, 60, & 76) and AVSS (pin 40) to ground.
2. Connect VCC (pins 53, 65 & 93), VTR (pin 18), and VREF (pin 44) to VCC (3.3V).
3. Connect an oscilloscope or voltmeter to FAN_TACH1 (pin 52).
4. All other pins should be tied to ground.
Testing
1. Turn power on.
2. With LAD0 (pin 20) and nLFRAME (pin 24) low, bring nPCI_RESET (pin 26) high. The chip is
now in XNOR chain test mode. At this point, all inputs to the XNOR chain are low. The output,
on FAN_TACH1 (pin 52), should also be low. Refer to INITIAL CONFIG on Truth Table 1.
3. Bring pin 100 high. The output on FAN_TACH1 (pin 52) should go high. Refer to STEP ONE
on Truth Table 1.
4. In descending pin order, bring each input high. The output should switch states each time an
input is toggled. Continue until all inputs are high. The output on FAN_TACH1 should now
be low. Refer to END CONFIG on Truth Table 1.
5. The current state of the chip is now represented by INITIAL CONFIG in Truth Table 2.
6. Each input should now be brought low, starting at pin one and continuing in ascending order.
Continue until all inputs are low. The output on FAN_TACH1 should now be low. Refer to
Truth Table 2.
7. To exit test mode, tie LAD0 (pin 20) OR nLFRAME (pin 24) high, and toggle nPCI_RESET
from a low to a high state.
INITIAL CONFIG
TRUTH TABLE 1 - Toggling Inputs In Descending Order
PIN PIN PIN PIN PIN PIN
100 99
98 97
96
... PIN 1
L
L
L
L
L
L
L
OUTPUT
PIN 52
L
STEP 1
H
L
L
L
L
L
L
H
STEP 2
H
H
L
L
L
L
L
L
STEP 3
H
H
H
L
L
L
L
H
STEP 4
H
H
H
H
L
L
L
L
STEP 5
H
H
H
H
H
L
L
H
…
…
…
……
…
…
…
…
STEP N
H
H
H
H
H
H
L
H
END CONFIG
H
H
H
H
H
H
H
L
INITIAL CONFIG
STEP 1
STEP 2
STEP 3
STEP 4
STEP 5
STEP N
END CONFIG
TRUTH TABLE 2 - Toggling Inputs In Ascending Order
PIN 1 PIN 2 PIN 3 PIN 4 PIN 5 PIN ... PIN 100
H
H
H
H
H
H
H
L
H
H
H
H
H
H
L
L
H
H
H
H
H
L
L
L
H
H
H
H
L
L
L
L
H
H
H
L
L
L
L
L
H
H
…
…
…
…
…
…
…
L
L
L
L
L
L
H
L
L
L
L
L
L
L
OUTPUT
PIN 52
L
H
L
H
L
H
…
H
L
SMSC LPC47B27x
- 195 -
DATASHEET
Rev. 04-17-07
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