| ??? 12/02/08 03:59 Read: times |
#160474 - How to rework the board? Responding to: ???'s previous message |
Dear Fren,
In that case all you need is an EXTERNAL flip-flop that gates !PSEN to either the RAM or the ROM instead of the negative OR you probably have there now. How to control the !PSEN using flip-flop? and What do you mean "instead of the negative OR you probably..." !RD and !PSEN are not always shared, make that selection (or sharing - figure it out) based on the status of a port pin. How to control RD and PSEN using port pin? I though if we want to add more xram for ROM and RAM on 8052 we have to !RD ANDs !PSEN. Thank you, Tang |
| Topic | Author | Date |
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