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Types of ROM (ROMの種類)

Mask-programmed ROM


  
Figure: A 4 $\times $ 4 ROM chip
\includegraphics[width=9cm]{/home/david/courses/comparch/lectures/memory/figs/rom.eps}

PROM (Programmable ROM)


  
Figure: A 4 $\times $ 4 PROM chip
\includegraphics[width=10cm]{/home/david/courses/comparch/lectures/memory/figs/prom.eps}

EPROM (Erasable PROM)


  
Figure 6.6: A floating-gate transistor used in EPROMs
\includegraphics[width=5cm]{/home/david/courses/comparch/lectures/memory/figs/eprom.eps}

Flash EPROM

EEPROM (Electrically Erasable PROM)


next up previous contents
Next: Comparison of ROM Types Up: Read Only Memory (ROM) Previous: Read Only Memory (ROM)
David Asano
2001-05-29