74377: Difference between revisions
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The 74377 chip is used as a latch in mappers like [[Color Dreams]] and stores eight bits of data | The [[74377]] chip (common variants 74LS377, 74HC377) is an octal D flip-flop, used as a latch in mappers like [[Color Dreams]] and stores eight bits of data. | ||
If only four or less bits are needed, a [[74161]] may be used instead. | |||
See also: [[74161#Latch Implementation|74161 Latch Implementation]] | |||
== 74377 Pinout == | |||
.--\/--. | |||
/WE -| 1 20|- Vcc | |||
Q0 -| 2 19|- Q7 | |||
D0 -| 3 18|- D7 | |||
D1 -| 4 17|- D6 | |||
Q1 -| 5 16|- Q6 | |||
Q2 -| 6 15|- Q5 | |||
D2 -| 7 14|- D5 | |||
D3 -| 8 13|- D4 | |||
Q3 -| 9 12|- Q4 | |||
GND -|10 11|- CLK | |||
`------' | |||
== Signal descriptions == | |||
*Vcc: Connect to +5V | |||
*GND: | |||
*CLK: Load clock | |||
*/WE: Write enable | |||
*D0-7: Inputs, connected to CPU D0-D7 | |||
*Q0-7: Outputs, connected to PRG and CHR ROM address lines | |||
D0-7 are copied to Q0-7 when CLK rises (0 to 1) while /WE is low. | |||
== References == | |||
*Philips Semiconductors. [http://www.alldatasheet.com/datasheet-pdf/pdf/15594/PHILIPS/74HC377.html 74HC377: Octal D-type flip-flop with data enable; positive-edge trigger] | |||
[[Category:7400 series|377]] | |||
Latest revision as of 23:05, 14 December 2022
The 74377 chip (common variants 74LS377, 74HC377) is an octal D flip-flop, used as a latch in mappers like Color Dreams and stores eight bits of data.
If only four or less bits are needed, a 74161 may be used instead.
See also: 74161 Latch Implementation
74377 Pinout
.--\/--.
/WE -| 1 20|- Vcc
Q0 -| 2 19|- Q7
D0 -| 3 18|- D7
D1 -| 4 17|- D6
Q1 -| 5 16|- Q6
Q2 -| 6 15|- Q5
D2 -| 7 14|- D5
D3 -| 8 13|- D4
Q3 -| 9 12|- Q4
GND -|10 11|- CLK
`------'
Signal descriptions
- Vcc: Connect to +5V
- GND:
- CLK: Load clock
- /WE: Write enable
- D0-7: Inputs, connected to CPU D0-D7
- Q0-7: Outputs, connected to PRG and CHR ROM address lines
D0-7 are copied to Q0-7 when CLK rises (0 to 1) while /WE is low.
References
- Philips Semiconductors. 74HC377: Octal D-type flip-flop with data enable; positive-edge trigger
