Email: Password: Remember Me | Create Account (Free)

Back to Subject List

Old thread has been locked -- no new posts accepted in this thread
???
12/09/17 02:39
Read: times


 		 #190825 - Old School SRAM Memory Expansion
Responding to: ???'s previous message
I'm thinking now that in the rest of the circuit, the SRAM address lines are all tied to TTL 74LSxx chips powered by +5v (rather than Vmem). So perhaps the switch upper position should be tied to +5v too. That way Axx (the highes addr line, that I am using for bank switching) will be at 0v when power is off, regardless of the switch position. For instance,


Save This Code

                  .------U-------
 +5v---.   Vmem---| Vcc
       |          |  
       |          |  
       <          |  
       < 1k       |   SRAM
       <          |  
       |   SPDT   |  
         /--------| Axx (highest addr line)
       |          |  
       |          |  
       <          |  
       < 10k      |  
       <
       |
       |
      ===  GND
       =

 

 


This means that in standby, Axx is always at 0v. Also, there is this knowledge base item:
https://community.cypress.com/docs/DOC-10268

List of 7 messages in thread
TopicAuthorDate
Old School SRAM Memory Expansion            01/01/70 00:00      
   Old School SRAM Memory Expansion            01/01/70 00:00      
   maybe this isn't the easiest way ...             01/01/70 00:00      
      Banked SRAM            01/01/70 00:00      
         maybe a peek at the SRAM datasheet would help            01/01/70 00:00      
   Suited pull-ups / pull-downs do the trick...            01/01/70 00:00      
      Thanks!            01/01/70 00:00      

Back to Subject List