Table 5-4. Truncated Port Addresses to R.A.M. in 22 Used Ports Configuration

T.O. 31W2-2GSC24-2

TM 11-5805-688-14-1

NAVELEX 0967-LP-545-3010

Table 5-4. Truncated Port Addresses to R.A.M. in 22 Used

Ports Configuration

Read Port Address

Counter 5-Bit Binary

to R.A.M. After

Equivalent

Output (After

Decimal

Reversal of Binary

Decimal

Truncation)

State

Weights

State

MSB LSB

11010

11011

11100

00111

11110

01111

loss-of-scan diagnostic latch generates signal MLEOS-

state when the self-test switch on the front panel is set to

when an error signal is applied to it. Signal MLEOS- is

the on (up) position. When the SELF TEST switch is set

applied to the display card to inhibit error indications from

to the off (down) position, error reset signal ERST- is

the channel cards that use MEOS2. An error, signal to

generated and resets the diagnostic circuits.

OR gate U47A sets the out-of-sequence diagnostic flip-

flop and generates error signal MSEQ- that is applied to

5-288. Error signal PSERR- is generated from the port

the display card. The output from U47A also sets the

sequence error detector when signal MMF=PS is

write/read control so that a write function to the R.A.M. is

generated at the same time that the port-is- in-sequence

generated for one scan time. In normal operation the

comparator output is A is greater than B. The A is

inhibit signal from the write/read control is applied to

greater than B signal indicates an unused port that

AND gate U39 during every other scan time to inhibit the

should not be serviced. In turn, the MMF=PS signal is

channel address comparator output for every other scan

developed only for active ports that are serviced. For

time. The comparator output is inhibited during the time

example, assuming that the maximum number of active

that a write function is being performed on the R.A.M. in

ports in a given system configuration is 22, minor frames

the channel address diagnostics. The inhibit prevents

23 and up are not used for overhead servicing of ports.

the comparator from initiating an error condition during

Therefore, when the MMF=PS signal is present, the

normal operation when the diagnostic R.A.M. is in the

comparator output should be A is not greater than B.

write mode. Therefore, a noncompare in the comparator

exists during the scan when the equipment is in the write

5-289. The channel address diagnostic circuits are a

mode.

When in the error state, the loss-of-scan

duplication of the functional circuits that produce the

diagnostic latch and/or the out-of-sequence diagnostic

channel addresses (MCHAD1 through MCHAD8). The

flip-flop resets when the RESET switch on the front panel

4-bit channel addresses from the diagnostic and

is pressed. Both diagnostic circuits are set to their error

functional circuits are

5-74