AT89S4051 Atmel Corporation, AT89S4051 Datasheet - Page 35

• 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

37. Power-down Sequence
38. ISP Byte Sequence
39. ISP Command Sequence
Figure 39-1. ISP Command Sequence
3390E–MICRO–6/08
SCK
SO
SI
7
7
OPCODE
???
Execute this sequence to power-down the device after programming.
Figure 37-1. ISP Power-down Sequence
Figure 38-1. ISP Byte Sequence
1. Set XTAL1 to “L” if a crystal is not used.
2. Bring RST to “L”.
3. Tri-state MOSI (P1.5).
1. Data shifts in/out MSB first.
2. MISO changes at rising of SCK.
3. MOSI is sampled at falling edge of SCK.
1. Byte Format: 4 byte packet (3 header bytes + 1 data byte)
2. Page Format: 35 byte packet (3 header bytes + 32 data bytes)
3. All bytes are required, even if they are don’t care.
P1.6/MISO
P1.5/MOSI
0
P1.7/SCK
0 7
P1.5/MOSI
P1.6/MISO
P1.7/SCK
7
XTAL1
RST
V
CC
ADDRH
???
7
7
High Z
6
6
0
0 7
7
data is sampled
5
5
ADDRL
4
4
???
3
3
0
High Z
AT89S2051/S4051
0 7
7
2
2
DATAOUT
DATAIN
1
1
0
0
0
0
35