ST72F321J ST Microelectronics, ST72F321J Datasheet - Page 16

• Manufacturer Part Number: ST72F321J
• Description: 8-BIT MCU
• Manufacturer: ST Microelectronics

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DataSheet
ST72321J
4 FLASH PROGRAM MEMORY
4.1 Introduction
The ST7 dual voltage High Density Flash
(HDFlash) is a non-volatile memory that can be
electrically erased as a single block or by individu-
al sectors and programmed on a Byte-by-Byte ba-
sis using an external V
The HDFlash devices can be programmed and
erased off-board (plugged in a programming tool)
or on-board using ICP (In-Circuit Programming) or
IAP (In-Application Programming).
The array matrix organisation allows each sector
to be erased and reprogrammed without affecting
other sectors.
4.2 Main Features
4.3 Structure
The Flash memory is organised in sectors and can
be used for both code and data storage.
Figure 4. Memory Map and Sector Address
16/179
Three Flash programming modes:
– Insertion in a programming tool. In this mode,
– ICP (In-Circuit Programming). In this mode, all
– IAP (In-Application Programming) In this
ICT (In-Circuit Testing) for downloading and
executing user application test patterns in RAM
Read-out protection against piracy
Register Access Security System (RASS) to
prevent accidental programming or erasing
4
all sectors including option bytes can be pro-
grammed or erased.
sectors including option bytes can be pro-
grammed or erased without removing the de-
vice from the application board.
mode, all sectors except Sector 0, can be pro-
grammed or erased without removing the de-
vice from the application board and while the
application is running.
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DFFFh
BFFFh
D7FFh
EFFFh
3FFFh
7FFFh
9FFFh
FFFFh
1000h
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4K
PP
8K
supply.
2 Kbytes
10K
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8 Kbytes
16K
4 Kbytes
4 Kbytes
16 Kbytes
24K
Depending on the overall Flash memory size in the
microcontroller device, there are up to three user
sectors (see
be erased independently to avoid unnecessary
erasing of the whole Flash memory when only a
partial erasing is required.
The first two sectors have a fixed size of 4 Kbytes
(see
of the ST7 addressing space so the reset and in-
terrupt vectors are located in Sector 0 (F000h-
FFFFh).
Table 3. Sectors available in Flash devices
4.3.1 Read-out Protection
Read-out protection, when selected, makes it im-
possible to extract the memory content from the
microcontroller, thus preventing piracy. Even ST
cannot access the user code.
In flash devices, this protection is removed by re-
programming the option. In this case, the entire
program memory is first automatically erased.
Read-out protection selection depends on the de-
vice type:
– In Flash devices it is enabled and removed
– In ROM devices it is enabled by mask option
Note: The LVD is not supported if the read-out
protection is enabled
through the FMP_R bit in the option byte.
specified in the Option List.
24 Kbytes
Flash Size (bytes)
32K
Figure
> 8K
4K
8K
40 Kbytes 52 Kbytes
4). They are mapped in the upper part
Table
48K
3). Each of these sectors can
60K
Available Sectors
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Sectors 0,1, 2
FLASH
MEMORY SIZE
SECTOR 2
SECTOR 1
SECTOR 0
Sectors 0,1
Sector 0
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