AT89C2051
12. Programming Interface
Every code byte in the Flash array can be written and the entire array can be erased by using
the appropriate combination of control signals. The write operation cycle is self-timed and once
initiated, will automatically time itself to completion.
Most major worldwide programming vendors offer support for the Atmel AT89 microcontroller
series. Please contact your local programming vendor for the appropriate software revision.
13. Flash Programming Modes
Mode
Write Code Data
Read Code Data
Bit - 1
Write Lock
Bit - 2
12V
H
H
L
L
RST/VPP
12V
H
12V
H
P3.2/PROG
P3.3
L
L
H
P3.4
H
L
H
P3.5
H
H
H
P3.7
H
H
H
Chip Erase
Read Signature Byte
Notes:
12V
H
H
(2)
H
L
L
L
L
L
L
L
1. The internal PEROM address counter is reset to 000H on the rising edge of RST and is advanced by a positive pulse at
XTAL1 pin.
2. Chip Erase requires a 10 ms PROG pulse.
3. P3.1 is pulled Low during programming to indicate RDY/BSY.
9
0368H–MICRO–6/08
ATMEL [ ATMEL CORPORATION ]
