9/20/6Lecture 14 - Static Memory1 Static Memory. 9/20/6Lecture 14 - Static Memory2 Static Memory.
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Transcript of 9/20/6Lecture 14 - Static Memory1 Static Memory. 9/20/6Lecture 14 - Static Memory2 Static Memory.
9/20/6 Lecture 14 - Static Memory 1
Static Memory
9/20/6 Lecture 14 - Static Memory 2
Static Memory
9/20/6 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 to 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.
9/20/6 Lecture 14 - Static Memory 4
Static RAM Characteristics Forms the bulk of memory in a system. 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
9/20/6 Lecture 14 - Static Memory 5
Static RAM Nonvolatile – as long as power is on value is retained
with no other action.
Data
Select
Data*
GND
Vcc
NMOS Memory cell
Data
Select
Data*
GND
Vcc
CMOS Memory cell
9/20/6 Lecture 14 - Static Memory 6
Gate Equivalent
Data
Select
Data*
GND
Vcc
CMOS Memory cell
9/20/6 Lecture 14 - Static Memory 7
1st approach to 16K of RAM
9/20/6 Lecture 14 - Static Memory 8
2nd approach to 16K of RAM
9/20/6 Lecture 14 - Static Memory 9
Internals of 6264LP Static CMOS RAM
9/20/6 Lecture 14 - Static Memory 10
A RAM Chip 6264LP-10 -10 means
100ns access time
Consider all parameters
9/20/6 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
9/20/6 Lecture 14 - Static Memory 12
Read cycle bus contention
9/20/6 Lecture 14 - Static Memory 13
Write cycle bus contention
9/20/6 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
9/20/6 Lecture 14 - Static Memory 15
PROM and EPROMS Come in many sizes Byte wide is very common Wordwide is also common
9/20/6 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.
9/20/6 Lecture 14 - Static Memory 17
EEPROMs and flash EEPROMs Flash EEPROMs are similar to electrical
erasable PROMs
9/20/6 Lecture 14 - Static Memory 18
Example of flash EEPROM use Flash
EEPROMs are similar to electrically erasable PROMs