AT89C51SND1_06 ATMEL [ATMEL Corporation], AT89C51SND1_06 Datasheet - Page 3

• Manufacturer Part Number: AT89C51SND1_06
• Description: USB Microcontrollers
• Manufacturer: ATMEL [ATMEL Corporation]

ISP Communication
Management
User Call Management Several Application Program Interface (API) calls are available to the application program to
Flash Memory
Management
Bootloader Configuration
Configuration and
Manufacturer
Information
Mapping and Default
Value of Hardware
Security Byte
4254C–MP3–03/06
The purpose of this process is to manage the communication and its protocol between the on-
chip bootloader and an external device (host). The on-chip bootloader implements a USB proto-
col (see Section “Protocol”, page 12). This process translates serial communication frames
(USB) into Flash memory accesses (read, write, erase...).
selectively erase and program Flash pages. All calls are made through a common interface (API
calls) included in the bootloader. The purpose of this process is to translate the application
request into internal Flash memory operations.
This process manages low level accesses to the Flash memory (performs read and write
accesses).
The following table lists Configuration and Manufacturer byte information used by the boot-
loader. This information can be accessed through a set of API or ISP commands.
Table 1. Configuration and Manufacturer Information
The 4 MSB of the Hardware Byte can be read/written by software (this area is called Fuse bits).
The 4 LSB can only be read by software and written by hardware using parallel programmer
devices, this area is called Lock bits.
Table 2. Hardware Byte Information
Note:
Mnemonic
BSB
SBV
SSB
EB
Manufacturer
Id1: Family Code
Id2: Product Name
Id3: Product Revision
Bit Position
7
6
5
4
3
2
1
0
U: Unprogrammed = 1
P: Programmed = 0
Mnemonic
reserved
BLJB
X2B
LB2
LB1
LB0
–
–
Description
Boot Status Byte
Software Boot Vector
Software Security Byte
Extra Byte
Default Value
U
U
U
U
U
U
P
P
Description
To start in x1 mode
To map the boot area in code area between F000h-FFFFh
To lock the chip (see datasheet)
AT89C51SND1
Default Value
FOh
DFh
FFh
FFh
FFh
D7h
58h
F7h
3