Digital Equipment AXPpci 33, Руководство по конструкции

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Physical Description
Figure 2–5 Keylock and Power LED Circuit
MR-6408-AI
2.2.2.10 LED Display Connector (J6)
The 16-position (2 x 8) LED display connector (J6) supplies power and
signals to an optional circuit board (system integrator provided) with
8 LEDs. The LEDs light with various codes to show the state of the
boot and power-up-self-test (POST) diagnostic firmware. The LEDs show
the results of writes to the lowest 8 bits of any address in the range
0.3880.0000 through 0.38ff.ffff. For consistency, it is recommended that
address 0.3880.0000 be used. At the successful conclusion of self-test, the
resulting code shows the cache size detected.
Use the LED ENABLE L signal to enable an 8-bit register chip such as
74F377, and the LEDCLK signal to strobe the 8 bits of data
(Data 0–Data 7) into the register on the rising edge.
Table 2–10 lists the pins and functions of the LED display connector.
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