AT89LP51 Atmel Corporation, AT89LP51 Datasheet - Page 79

• Manufacturer Part Number: AT89LP51
• Manufacturer: Atmel Corporation

Specifications of AT89LP51

• Flash (kbytes): 4 Kbytes
• Max. Operating Frequency: 20 MHz
• Cpu: 8051-1C
• Max I/o Pins: 36
• Uart: 1
• Sram (kbytes): 0.25
• Eeprom (bytes): 256
• Self Program Memory: IAP
• Operating Voltage (vcc): 2.4 to 5.5
• Timers: 3
• Isp: SPI
• Watchdog: Yes

17. Programming the Flash Memory
17.1
3709D–MICRO–12/11
Physical Interface
The Atmel AT89LP51/52 microcontroller features 8K bytes of on-chip In-System Programmable
Flash program memory and 256bytes of nonvolatile Flash data memory. In-System Program-
ming allows programming and reprogramming of the microcontroller positioned inside the end
system. Using a simple 3-wire SPI interface, the programmer communicates serially with the
AT89LP51/52 microcontroller, reprogramming all nonvolatile memories on the chip. In-System
Programming eliminates the need for physical removal of the chips from the system. This will
save time and money, both during development in the lab, and when updating the software or
parameters in the field. The programming interface of the AT89LP51/52 includes the following
features:
For more detailed information on In-System Programming, refer to the Application Note entitled
“AT89LP In-System Programming Specification”.
The AT89LP51/52 provides a standard programming command set with two physical interfaces:
a bit-serial and a byte-parallel interface. Normal Flash programming utilizes the Serial Peripheral
Interface (SPI) pins of an AT89LP51/52 microcontroller. The SPI is a full-duplex synchronous
serial interface consisting of three wires: Serial Clock (SCK), Master-In/Slave-out (MISO), and
Master-out/Slave-in (MOSI)). When programming an AT89LP51/52 device, the programmer
always operates as the SPI master, and the target system always operates as the SPI slave. To
enter or remain in Programming mode the device’s reset line (RST) must be held active. With
the addition of VDD and GND, an AT89LP51/52 microcontroller can be programmed with a min-
imum of seven connections as shown in
Figure 17-1. In-System Programming Device Connections
• Three-wire serial SPI Programming Interface or 11-pin Parallel Interface
• Selectable Polarity Reset Entry into Programming
• User Signature Array
• Flexible Page Programming
• Row Erase Capability
• Page Write with Auto-Erase Commands
• Programming Status Register
Serial Clock
Serial Out
Serial In
P1.7/SCK
P1.6/MISO
P1.5/MOSI
GND
Figure
AT89LP51/52
17-1.
VDD
POL
RST
GND or VDD
RST
AT89LP51/52
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