Atmel AT89C2051 Manual page 9

12. Programming Interface
13. Flash Programming Modes
Mode
(1)(3)
Write Code Data
(1)
Read Code Data
Write Lock
Chip Erase
Read Signature Byte
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
XTAL1 pin.
2. Chip Erase requires a 10 ms PROG pulse.
3. P3.1 is pulled Low during programming to indicate RDY/BSY.
0368G–MICRO–6/05
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.
RST/VPP
12V
Bit - 1 12V
Bit - 2 12V
12V
P3.2/PROG
H H
H H
P3.3 P3.4
L H
L L
H H
H H
(2)
H L
L L
AT89C2051
P3.5 P3.7
H H
H H
H H
L L
L L
L L
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