AT89C4051
Reading the Signature Bytes: The signature bytes are
read by the same procedure as a normal verification of
locations 000H, 001H, and 002H, except that P3.5 and
P3.7 must be pulled to a logic low. The values returned are
as follows.
Programming Interface
Every code byte in the Flash array can be written and the
entire array can be erased by using the appropriate combi-
nation of control signals. The write operation cycle is self-
timed and once initiated, will automatically time itself to
completion.
(000H) = 1EH indicates manufactured by Atmel
(001H) = 41H indicates 89C4051
All major programming vendors offer worldwide support for
the Atmel microcontroller series. Please contact your local
programming vendor for the appropriate software revision.
Flash Programming Modes
Mode
RST/VPP
P3.2/PROG
P3.3
P3.4
P3.5
P3.7
Write Code Data(1)(3)
12V
L
H
H
H
Read Code Data(1)
Write Lock
H
H
L
L
H
H
H
H
Bit - 1
Bit - 2
12V
H
H
12V
12V
H
H
H
L
H
L
L
L
L
L
L
L
L
Chip Erase
(2)
Read Signature Byte
H
Notes: 1. The internal PEROM address counter is reset to 000H on the rising edge of RST and is advanced by a positive pulse at
XTAL 1 pin.
2. Chip Erase requires a 10-ms PROG pulse.
3. P3.1 is pulled Low during programming to indicate RDY/BSY.
7
ATMEL [ ATMEL ]
