1. C.k. Pithawalla Collage of Engineering & Technology surat

2. C.k. Pithawalla Collage of Engineering & Technology surat
NAME EN NO Dhodia Hardik thakorbhai Patel Krunal Sanjaybhai Patel vivek Gambhirbhai Raj Chirag Sureshbhai

3. Draw and explain interfacing of external program ROM with 8051
TOPIC
Draw and explain interfacing of external program ROM with 8051
SEMICONDUCTOR MEMORY
Memory organization
Memory chips are organized into a number of locations within the IC.
Each location can hold 1 bit, 4 bits, 8 bits, or even 16 bits, depending on how it is designed internally.

4. SEMICONDUCTOR MEMORY Speed The speed of the memory chip
is commonly referred to as
its access time.
The access time of memory chips
varies from a few nanoseconds to
hundreds of nanoseconds,
depending on the IC technology
used in the design and
abrication process.

5. SEMICONDUCTOR MEMORY
ROM (read-only memory)
ROM is a type of memory that does not lose its contents when the power is turned off.
For this reason, ROM is also called nonvolatile memory.

6. SEMICONDUCTOR MEMORY
PROM (programmable ROM) and OTP
PROM is programmed by blowing the fuses.
If the information burned into PROM is wrong, that PROM must be discarded since its internal fuses are blown permanently.

7. EPROM (erasable programmable ROM) and UV-EPROM
SEMICONDUCTOR MEMORY
EPROM (erasable programmable ROM) and UV-EPROM
Pin Configurations for 27xx ROM Family

8. SEMICONDUCTOR MEMORY

9. SEMICONDUCTOR MEMORY
EEPROM (electrically erasable programmable ROM)

10. SEMICONDUCTOR MEMORY SRAM (static RAM) Storage cells in static
RAM memory are
made of flip-flops
and therefore do
not require refreshing
in order to keep
their data.
This is in contrast
to DRAM.

11. SEMICONDUCTOR MEMORY

12. 8051 INTERFACING WITH EXTERNAL ROM
EA pin
Connect the EA pin
to Vcc to indicate that
the program code is
stored in the mC's
on-chip ROM.
To indicate that the program
code is stored in external ROM,
this pin must be connected
to GND.

13. 8051 INTERFACING WITH EXTERNAL ROM
Figure 14–8
74LS373 D Latch
(Reprinted by permission of Texas Instruments,
Copyright Texas Instruments, 1988)

14. 8051 INTERFACING WITH EXTERNAL ROM
Figure 14–9 Address/Data Multiplexing

15. 8051 INTERFACING WITH EXTERNAL ROM
Figure 14– Data, Address, and Control Buses for the 8031

16. 8051 INTERFACING WITH EXTERNAL ROM
8031 Connection to External Program ROM

17. 8051 INTERFACING WITH EXTERNAL ROM
PSEN

18. 8051 INTERFACING WITH EXTERNAL ROM
On-chip and off-chip code ROM
In such a system we still have EA = Vcc, meaning that upon reset the 8051 executes the on-chip program first; then, when it reaches the end of the on-chip ROM it switches to external ROM for the rest of the program code.

19. THANK YOU