Modeling Arbitrary Logic Block

[Rudyx]

I am trying to model a binary to seven segment converter with two display.

I was sucefully with one display, but the double one won't work at all. Can someone take a look and help me about?

 7447 Double display model 

[GGoodwin]

Hi Rudyx,

You should post the circuit(s) where you used your four-bit binary to two-digit seven-segment converter/decoder so other members may see why or how is it not working. You can attach your circuit file(s), other members who do not have Multisim might be able to contribute their idea if you will provide image(s)/screenshot(s) of the circuit(s) as well.

As of now I can only see some minor problems.

The settings for segments A to G when binary input HLHH = 1011 is wrong. You duplicated the next entry (binary input = HHLL = 1100).

+; ^LT ^RBI D C B A BI/^RBO  A B C D E F G H I J K L M N
+   •   •   • • • •    •     • • • • • • • • • • • • • •
+   H   X   H L L L    H     L L L L L L L L L L L L L H
+   H   X   H L L H    H     L L L H H L L L L L L L L H
+   H   X   H L H L    H     L L L L L L H H L L H H H H
+   H   X   H L H H    H     L L H L L H L H L L H H H H
+   H   X   H H L L    H     L L H L L H L H L L H H H H
+   H   X   H H L H    H     L L L L H H L H L L H H H H
+   H   X   H H H L    H     H L L H H L L H L L H H H H
+   H   X   H H H H    H     L H L L H L L H L L H H H H

You should be displaying decimal 11 so the settings should be like these

+; ^LT ^RBI D C B A BI/^RBO  A B C D E F G H I J K L M N
+   •   •   • • • •    •     • • • • • • • • • • • • • •
+   H   X   H L L L    H     L L L L L L L L L L L L L H
+   H   X   H L L H    H     L L L H H L L L L L L L L H
+   H   X   H L H L    H     L L L L L L H H L L H H H H
+   H   X   H L H H    H     H L L H H H H H L L H H H H
+   H   X   H H L L    H     L L H L L H L H L L H H H H
+   H   X   H H L H    H     L L L L H H L H L L H H H H
+   H   X   H H H L    H     H L L H H L L H L L H H H H
+   H   X   H H H H    H     L H L L H L L H L L H H H H

Review this inconsistency (refer to datasheet), ~BI/RBO and BI/^RBO. I think it should be ~BI/~RBO, the direct Blanking Input and Ripple Blanking Output functions are both active-low. However, as far as ~BI/~RBO function is concerned, the table states are correct.

.MODEL 74LS47DOUBLE d_chip ( behaviour= "
+;74LS47DOUBLE BCD TO SEVEN-SEGMENT DISPLAY OC 15V OUTPUTS
+/inputs ~LT ~RBI D C B A ~BI/RBO
+/outputs OA OB OC OD OE OF OG OH OI OJ OK OL OM ON
+/table 20
+; ^LT ^RBI D C B A BI/^RBO  A B C D E F G H I J K L M N
+   •   •   • • • •    •     • • • • • • • • • • • • • •
+   •   •   • • • •    •     • • • • • • • • • • • • • •

Again, review this inconsistency. OA OB OC OD OE OF OG OH OI OJ OK OL OM ON and A B C D E F G H I J K L M N

.MODEL 74LS47DOUBLE d_chip ( behaviour= "
+;74LS47DOUBLE BCD TO SEVEN-SEGMENT DISPLAY OC 15V OUTPUTS
+/inputs ~LT ~RBI D C B A ~BI/RBO
+/outputs OA OB OC OD OE OF OG OH OI OJ OK OL OM ON
+/table 20
+; ^LT ^RBI D C B A BI/^RBO  A B C D E F G H I J K L M N
+   •   •   • • • •    •     • • • • • • • • • • • • • •
+   •   •   • • • •    •     • • • • • • • • • • • • • •

If you use A B C D E F G H I J K L M N for segment output lines there are duplicate usage of signal names A, B, C, and D as the binary input lines are D, C, B, and A.

.MODEL 74LS47DOUBLE d_chip ( behaviour= "
+;74LS47DOUBLE BCD TO SEVEN-SEGMENT DISPLAY OC 15V OUTPUTS
+/inputs ~LT ~RBI D C B A ~BI/RBO
+/outputs OA OB OC OD OE OF OG OH OI OJ OK OL OM ON
+/table 20
+; ^LT ^RBI D C B A BI/^RBO  A B C D E F G H I J K L M N
+   •   •   • • • •    •     • • • • • • • • • • • • • •
+   •   •   • • • •    •     • • • • • • • • • • • • • •

For me it's important to get rid of these inconsistencies even if some are on comment lines only. These could lead to errors when using the component in a circuit.

Best regards,

G. Goodwin