Datasheet

18
4341H–MP3–10/07
AT8xC51SND2C/MP3B
6. Program/Code Memory
The AT8xC51SND2C execute up to 64K Bytes of program/code memory. Figure 6-1 shows the
split of internal and external program/code memory spaces depending on the product.
The AT83SND2C product provides the internal program/code memory in ROM memory while
the AT89C51SND2C product provides it in Flash memory. These 2 products do not allow exter-
nal code memory execution.
The Flash memory increases EPROM and ROM functionality by in-circuit electrical erasure and
programming. The high voltage needed for programming or erasing Flash cells is generated on-
chip using the standard V
DD
voltage, made possible by the internal charge pump. Thus, the
AT89C51SND2C can be programmed using only one voltage and allows In-application software
programming. Hardware programming mode is also available using common programming
tools. See the application note Programming T89C51x and AT89C51x with Device
Programmers’.
The AT89C51SND2C implements an additional 4K Bytes of on-chip boot Flash memory pro-
vided in Flash memory. This boot memory is delivered programmed with a standard boot loader
software allowing In-System Programming (ISP). It also contains some Application Program-
ming Interface routines named API routines allowing In Application Programming (IAP) by using
user’s own boot loader.
Figure 6-1. Program/Code Memory Organization
4K Bytes
Boot Flash
FFFFh
F000h
0000h
64K Bytes
Code Flash
FFFFh
AT89C51SND2C
0000h
64K Bytes
Code ROM
FFFFh
AT83SND2C
F000h