AT89C1051 ATMEL Corporation, AT89C1051 Datasheet - Page 7

• Manufacturer Part Number: AT89C1051
• Description: 8-Bit Microcontroller with 1K Byte Flash
• Manufacturer: ATMEL Corporation

Chip Erase: The entire PEROM array (1K byte) and the
two Lock Bits are erased electrically by using the proper
combination of control signals and by holding P3.2 low for
10 ms. The code array is written with all “1”s in the Chip
Erase operation and must be executed before any non-
blank memory byte can be re-programmed.
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.
Figure 3. Programming the Flash Memory
PROGRAMMING
MODES TABLE
ADDRESS COUNTER
SEE FLASH
(000H) = 1EH indicates manufactured by Atmel
(001H) = 11H indicates 89C1051
TO INCREMENT
RDY/BSY
PROG
P3.1
P3.2
P3.3
P3.4
P3.5
P3.7
XTAL1
GND
AT89C1051
RST
V
P1
CC
5V
PGM
DATA
V / V
I H
PP
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.
Figure 4. Verifying the Flash Memory
PROGRAMMING
MODES TABLE
SEE FLASH
V
I H
P3.2
P3.3
P3.4
P3.5
P3.7
XTAL1
GND
AT89C1051
RST
V
P1
CC
5V
DATA
PGM
V
I H
4-9