AT89S4051 Atmel Corporation, AT89S4051 Datasheet - Page 27

• 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

29. Read User Signature Row
3390E–MICRO–6/08
Function:
Usage:
Figure 29-1. Read User Signature Row Sequence
1. Reads 1 to 32 bytes of data from 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.
1. Execute the Load-X command to set the page to 00H and reset the offset.
2. Apply “1000” TestCode to P3.7, P3.5, P3.4, P3.3.
3. Read 8-bit data on Port P1.
4. For additional bytes (up to 32), pulse XTAL1 high for at least 100 ns to increment the Y-
RDY/BSY
P3.3 - P3.7
P1.0 - P1.7
address and repeat step 3. The address will change on the falling edge of XTAL1.
XTAL1
P3.2
00H
1101
DOUT0
1000
DOUT1
AT89S2051/S4051
DOUT N-1
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