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