AT89S4051 Atmel Corporation, AT89S4051 Datasheet - Page 22

• Manufacturer Part Number: AT89S4051
• Manufacturer: Atmel Corporation

Specifications of AT89S4051

• Flash (kbytes): 4 Kbytes
• Max. Operating Frequency: 24 MHz
• Cpu: 8051-12C
• Max I/o Pins: 15
• Uart: 1
• Sram (kbytes): 0.25
• Operating Voltage (vcc): 2.7 to 5.5
• Timers: 2
• Isp: SPI

22. Power-up Sequence
23. Power-down Sequence
22
AT89S2051/S4051
Execute the following sequence to power-up the device before programming.
Figure 22-1. Power-up Operation
Execute the following sequence to power-down the device after programming.
Figure 23-1. Power-down Operation
1. Apply power between VCC and GND pins.
2. After V
3. Wait 4 ms for the internal Power-on Reset to timeout.
4. Bring P3.2 to “H” and drive P3.7, P3.5, P3.4, and P3.3 to known values, then wait
5. Raise RST/V
6. After V
1. Tri-state Port P1.
2. Bring RST/V
3. Bring XTAL and P3.2 to “L” and tri-state P3.7, P3.5, P3.4, and P3.3.
4. Bring RST to “L” and wait 10 µs.
5. Power off V
10 µs.
P1.0 - P1.7
P3.3 - P3.7
P1.0 - P1.7
P3.3 - P3.7
RDY/BSY
RDY/BSY
RST/V
CC
PP
RST/V
XTAL1
XTAL1
has settled, wait an additional 10 µs before programming.
has settled, wait 10 µs and bring RST to “H”.
V
P3.2
P3.2
V
CC
CC
PP
CC
PP
PP
PP
.
down from 12V to V
to 12V to enable the parallel programming modes.
High Z
High Z
High Z
CC
and wait 10 µs.
High Z
High Z
High Z
3390E–MICRO–6/08