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8051AHP View Datasheet(PDF) - Intel

Part NameDescriptionManufacturer
8051AHP MCS@51 8-BIT CONTROL-ORIENTED MICROCONTROLLERS Intel
Intel Intel
8051AHP Datasheet PDF : 21 Pages
First Prev 11 12 13 14 15 16 17 18 19 20
MCS@51 CONTROLLER
QUICK-PULSE PROGRAMMING
ALGORITHM
The 875XBH can be programmed using the Quick-
Pulse Programming Algorithm for microcontrollers.
The features of the new programming method are a
lower Vpp (12.75 volts as compared to 21 volts) and
a shorter programming pulse. For example, it is pos-
sible to program the entire 8 Kbytes of 875XBH
EPROM memory in less than 25 seconds with this
algorithm!
To program the part using the new~rithm, Vpp
must be 12,75 f 0.25 Volts. ALE/PROG is pulsed
low for 100 pseconds, 25 times as shown in
Figure 9, Then, the byte just programmed may be
verified. After programming, the entire array should
be verified. The Program Lock features are pro-
grammed using the same method, but with the setup
as shown in Table 4. The only difference in program-
ming Lock features is that the Lock features cannot
be directly verified. Instead, verification of program-
ming is by observing that their features are enabled.
PROGRAM VERIFICATION
If the Lock Bits have not been programmed, the on-
chip Program Memory can be read out for verifica-
tion purposes, if desired, either during or after the
programming operation. The address of the Program
Memory location to be read is applied to Port 1 and
pins P2.O - P2.4. The other pins should be held at
the “Verify” levels indicated in Table 1. The con-
tents of the addressed location will come out on Port
O. External pullups are required on Port O for this
operation. (If the Encryption Array in the EPROM
has been programmed, the data present at Port O
will be Code Data XNOR Encryption Data. The user
must know the Encryption Array contents to manual-
ly “unencrypt” the data during verify.)
The setup, which is shown in Figure 10, is the same
as for programming the EPROM except that pin P2.7
is held at a logic low, or may be used as an active
low read strob~.
, ~25p”LsEs ~
ALEM
ALE/PROG:
0
n--------
10 P,MIN
I“
100JM
*lops
1
Figure9. PROGWaveforma
272318-16
+~v
AO-A7
1
L‘r-F’ u 4-6MHz
h 10kJl
Vcc
X8
P!
Po
PGM
DATA
RST
rmpp
P3.6
P3.7
ALE/PRW
B75xBH =
P2.7
XTAL2
P2.6
1
0
0 (i-mm
0
XTAL1
Vss
P2.O
-P2.4
A8-A12
F
=
272318-17
Figure10.Verifyingthe EPROM
18
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