AT89S2051 Atmel Corporation, AT89S2051 Datasheet - Page 26

• Manufacturer Part Number: AT89S2051
• Manufacturer: Atmel Corporation

Specifications of AT89S2051

• Flash (kbytes): 2 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

28. Page Write User Signature Row
26
AT89S2051/S4051
Function:
Usage:
Note:
Figure 28-1. Page Write User Signature Row Sequence
1. Programs 1 to 32 bytes of data into the User Signature Row.
2. X-address (page) should be 00H from a previous Load-X command.
3. Y-address (offset) incremented by positive pulse on XTAL1.
4. 1 byte of data is loaded from Port P1 for the current Y-address by a low pulse on P3.2.
5. Disabled if User Row Fuse bit is disabled.
1. Execute the Load-X command to set the page to 00H and reset the offset.
2. Apply “0000” TestCode to P3.7, P3.5, P3.4, P3.3.
3. Drive Port P1 with 8-bit data.
4. Pulse P3.2 low for 1 µs to load the data from Port P1.
5. For additional bytes (up to 32), pulse XTAL1 high for at least 100 ns to increment the Y-
6. Wait 2 ms, monitor P3.1, or poll data.
RDY/BSY
P3.3 - P3.7
P1.0 - P1.7
address and repeat steps 3 and 4 within 150 µs.
It is possible to skip bytes by pulsing XTAL1 high multiple times before pulsing P3.2 low.
XTAL1
P3.2
00H
1101
DIN0
0000
DIN1
DIN N-1
3390E–MICRO–6/08