AT89C51RE2 Atmel Corporation, AT89C51RE2 Datasheet - Page 56

• Manufacturer Part Number: AT89C51RE2
• Manufacturer: Atmel Corporation

Specifications of AT89C51RE2

• Flash (kbytes): 128 Kbytes
• Max. Operating Frequency: 60 MHz
• Cpu: 8051-12C
• Max I/o Pins: 34
• Spi: 1
• Uart: 2
• Sram (kbytes): 8.25
• Self Program Memory: API
• Operating Voltage (vcc): 2.7 to 5.5
• Timers: 4
• Isp: UART/OCD
• Watchdog: Yes

ISP Protocol
Description
Physical Layer
Frame Description
56
AT89C51RE2
The UART used to transmit information has the following configuration:
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The Serial Protocol is based on the Intel Extended Hex-type records.
Intel Hex records consist of ASCII characters used to represent hexadecimal values and are
summarized below.
Table 33. Intel Hex Type Frame
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Record Mark ‘:’
Character: 8-bit data
Parity: none
Stop: 1 bit
Flow control: none
Baud rate: autobaud is performed by the bootloader to compute the baud rate chosen by the
host.
Record Mark:
–
Record length:
–
Load Offset:
–
–
Record Type:
–
Data/Info:
–
Checksum:
–
1 byte
Record Mark is the start of frame. This field must contain’:’.
Record length specifies the number of Bytes of information or data which follows the
Record Type field of the record.
Load Offset specifies the 16-bit starting load offset of the data Bytes, therefore this
field is used only for
Data Program Record.
Record Type specifies the command type. This field is used to interpret the
remaining information within the frame.
Data/Info is a variable length field. It consists of zero or more Bytes encoded as pairs
of hexadecimal digits. The meaning of data depends on the Record Type.
Checksum is the two’s complement of the 8-bit Bytes that result from converting
each pair of ASCII hexadecimal digits to one Byte of binary, thus including all field
from the Record Length field to the last Byte of the Data/Info field. Therefore, the
sum of all the ASCII pairs in a record after converting to binary, including all field from
the Record Length field to the Checksum field, is zero.
Record length
1 byte
Load Offset
2 bytes
Record Type
1 bytes
Data or Info
n byte
7663E–8051–10/08
Checksum
1 byte