AT89S51-24 Просмотр технического описания (PDF) - Atmel Corporation
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AT89S51-24 Datasheet PDF : 32 Pages
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5. At the end of a programming session, RST can be set low to commence normal device
operation.
Power-off sequence (if needed):
1. Set XTAL1 to “L” (if a crystal is not used).
2. Set RST to “L”.
3. Turn VCC power off.
Data Polling: The Data Polling feature is also available in the serial mode. In this mode, during
a write cycle an attempted read of the last byte written will result in the complement of the MSB
of the serial output byte on MISO.
16.2 Serial Programming Instruction Set
The Instruction Set for Serial Programming follows a 4-byte protocol and is shown in the
”Serial Programming Instruction Set” on page 20.
17. Programming Interface – Parallel Mode
Every code byte in the Flash array can be programmed 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 worldwide support for the Atmel AT89 micro-
controller series. Please contact your local programming vendor for the appropriate software
revision.
Table 17-1. Flash Programming Modes
ALE/
EA/
P0.7-0
P2.3-0
P1.7-0
Mode
VCC RST PSEN PROG
VPP
P2.6 P2.7 P3.3 P3.6 P3.7
Data
Address
Write Code Data
5V
H
L
(2)
12V
L
H
H
H
H
DIN
A11-8
A7-0
Read Code Data 5V
H
L
Write Lock Bit 1
5V
H
L
H
H
L
L
L
H
H
DOUT
A11-8
A7-0
(3)
12V
H
H
H
H
H
X
X
X
Write Lock Bit 2
5V
H
L
(3)
12V
H
H
H
L
L
X
X
X
Write Lock Bit 3
5V
H
L
(3)
12V
H
L
H
H
L
X
X
X
Read Lock Bits
P0.2,
5V
H
L
H
H
H
H
L
H
L
P0.3,
X
X
1, 2, 3
P0.4
Chip Erase
5V
H
L
(1)
12V
H
L
H
L
L
X
X
X
Read Atmel ID
5V
H
L
H
H
L
L
L
L
L
1EH
0000
00H
Read Device ID
5V
H
L
H
H
L
L
L
L
L
51H
0001
00H
Read Device ID
5V
H
L
H
H
L
L
L
L
L
06H
0010
00H
Notes:
1. Each PROG pulse is 200 ns - 500 ns for Chip Erase.
2. Each PROG pulse is 200 ns - 500 ns for Write Code Data.
3. Each PROG pulse is 200 ns - 500 ns for Write Lock Bits.
4. RDY/BSY signal is output on P3.0 during programming.
5. X = don’t care.
16
AT89S51
2487C–MICRO–03/05
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