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Static Memory

Static Memory

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Static Memory

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  1. Static Memory Lecture 14 - Static Memory

  2. Static Memory Lecture 14 - Static Memory

  3. Static Memory Systems • Those semiconductor components in a microcomputer that store the program and data. • Role in the system can be seen as passive – memory simply stores information and except for specialized architectures, performs no operation on the data stored there. • Today it is common to have yyG bytes in a system. Lecture 14 - Static Memory

  4. RAM Characteristics • Forms the bulk of memory in a system. • Today the bulk memory is typically a flavor of DRAM • Is read/write memory. • For read/write memory have choice of • Static RAM • Dynamic RAM • Special Characteristic Memory • ROM (PROM, EPROM, EEPROM) • EEPROM partially used as RAM • Computational Memory Lecture 14 - Static Memory

  5. Static RAM • Nonvolatile – as long as power is on value is retained with no other action. Lecture 14 - Static Memory

  6. Gate Equivalent Lecture 14 - Static Memory

  7. 1st approach to 16K of RAM Lecture 14 - Static Memory

  8. 2nd approach to 16K of RAM Lecture 14 - Static Memory

  9. Internals of 6264LP Static CMOS RAM Lecture 14 - Static Memory

  10. A RAM Chip • 6264LP-10 • -10 means 100ns access time • Consider all parameters Lecture 14 - Static Memory

  11. Bus Contention • Read after read to same chip • Must consider what happens in preceding cycle and what happens in next cycle • Must also consider read after write, write after read, and write after write timing • Timing for the same chip and for different chips Lecture 14 - Static Memory

  12. Read cycle bus contention Lecture 14 - Static Memory

  13. Write cycle bus contention Lecture 14 - Static Memory

  14. PROM and EPROM • Programmable Read Only Memory • One time programmable • Electrically Programmable Read Only Memory • Programmed by provided a higher than normal programming voltage – 12V to 25V • UV erasable • Used to program and code startup code – the bios in a PC Lecture 14 - Static Memory

  15. PROM and EPROMS • Come in many sizes • Byte wide is very common • Worldwide is also common Lecture 14 - Static Memory

  16. EEPROM • Another form of non-volatile memory • Read cycle is like other PROMs • Write cycle timing is long – typically over 100 us. Lecture 14 - Static Memory

  17. EEPROMs and flash EEPROMs • Flash EEPROMs are similar to electrical erasable PROMs Lecture 14 - Static Memory

  18. Example of flash EEPROM use • Flash EEPROMs are similar to electrically erasable PROMs Lecture 14 - Static Memory

  19. Wikipedia provides some info • Wikipedia provides some useful overview of the topic of the various non-volatile technologies. Lecture 14 - Static Memory