AT89C51AC2 Atmel Corporation, AT89C51AC2 Datasheet - Page 6

• Manufacturer Part Number: AT89C51AC2
• Manufacturer: Atmel Corporation

Specifications of AT89C51AC2

• Flash (kbytes): 32 Kbytes
• Max. Operating Frequency: 40 MHz
• Cpu: 8051-12C
• Max I/o Pins: 34
• Uart: 1
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 62.5
• Sram (kbytes): 1.25
• Eeprom (bytes): 2048
• Self Program Memory: API
• Operating Voltage (vcc): 3.0 to 5.5
• Timers: 4
• Isp: UART
• Watchdog: Yes

In-System
Programming
Boot Process
Hardware Condition
6
A/T89C51AC2 UART Bootloader
The ISP allows the user to program or reprogram a microcontroller’s on-chip Flash memory
through the serial line without removing it from the system and without the need of a pre-pro-
grammed application.
This section describes how to start the UART bootloader and the higher level protocols over the
serial line.
The bootloader can be activated in two ways:
•
•
The Hardware Conditions (EA = 1, PSEN = 0) during the RESET falling edge force the on-chip
bootloader execution. In this way the bootloader can be carried out whatever the user Flash
memory content.
As PSEN is an output port in normal operating mode (running user application or bootloader
code) after reset, it is recommended to release PSEN after falling edge of reset signal. The hard-
ware conditions are sampled at reset signal falling edge, thus they can be released at any time
when reset input is low.
Hardware condition
Regular boot process
4231D–CAN–03/08