7485: Difference between revisions
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The | The [[7485]] (74LS85, 74HC85) is a digital magnitude comparator IC. | ||
== 7485 Pinout == | |||
.--\/--. | |||
B3 --+ +-- Vcc | |||
IA<B --+ +-- A3 | |||
IA=B --+ +-- B2 | |||
IA>B --+ 85 +-- A2 | |||
QA>B --+ +-- A1 | |||
QA=B --+ +-- B1 | |||
QA<B --+ +-- A0 | |||
GND --+ +-- B0 | |||
`------' | |||
== Signal descriptions == | |||
* A3-A0: 4-bit number A | * A3-A0: 4-bit number A | ||
* B3-B0: 4-bit number B | * B3-B0: 4-bit number B | ||
| Line 21: | Line 21: | ||
* QA=B: False if A < B or A > B | * QA=B: False if A < B or A > B | ||
* QA>B: False if A < B, true if A > B | * QA>B: False if A < B, true if A > B | ||
If A | |||
If A is not equal to B, the cascading inputs have no effect. | |||
This IC has been proposed as the PRG ROM decoder for [[NROM-368]]. | This IC has been proposed as the PRG ROM decoder for [[NROM-368]]. | ||
[[Category: | == References == | ||
* [http://www.ti.com/lit/ds/sdls123/sdls123.pdf TI 7485 datasheet] | |||
[[Category:7400 series|085]] | |||
Latest revision as of 10:33, 28 October 2018
The 7485 (74LS85, 74HC85) is a digital magnitude comparator IC.
7485 Pinout
.--\/--.
B3 --+ +-- Vcc
IA<B --+ +-- A3
IA=B --+ +-- B2
IA>B --+ 85 +-- A2
QA>B --+ +-- A1
QA=B --+ +-- B1
QA<B --+ +-- A0
GND --+ +-- B0
`------'
Signal descriptions
- A3-A0: 4-bit number A
- B3-B0: 4-bit number B
- IA<B: Cascade from next lower nibble (use false for lowest)
- IA=B: Cascade from next lower nibble (use true for lowest)
- IA>B: Cascade from next lower nibble (use false for lowest)
- QA<B: True if A < B, false if A > B
- QA=B: False if A < B or A > B
- QA>B: False if A < B, true if A > B
If A is not equal to B, the cascading inputs have no effect.
This IC has been proposed as the PRG ROM decoder for NROM-368.
