ST7265X View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

ST7265X

Low speed USB 8-bit MCU family with up to 32 KB Flash/ROM

STMicroelectronics 

ST7265x

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 VPP supply.

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

s Three Flash programming modes:

– Insertion in a programming tool. In this mode,

all sectors including option bytes can be pro-

grammed or erased.

– ICP (In-Circuit Programming). In this mode, all

sectors including option bytes can be pro-

grammed or erased without removing the de-

vice from the application board.

– IAP (In-Application Programming) In this

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.

s ICT (In-Circuit Testing) for downloading and

executing user application test patterns in RAM

s Read-out protection against piracy

s Register Access Security System (RASS) to

prevent accidental programming or erasing

Figure 12. Memory Map and Sector Address

4.3 Structure

The Flash memory is organised in sectors and can

be used for both code and data storage.

Depending on the overall Flash memory size in the

microcontroller device, there are up to three user

sectors (see Table 5). Each of these sectors can

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 Figure 12). They are mapped in the upper

part of the ST7 addressing space so the reset and

interrupt vectors are located in Sector 0 (F000h-

FFFFh).

Table 5. Sectors available in Flash devices

Flash Memory Size

(bytes)

4K

8K

> 8K

Available Sectors

Sector 0

Sectors 0,1

Sectors 0,1, 2

4.4 Program Memory Read-out Protection

The read-out protection is enabled through an op-

tion bit.

When this option is selected, the programs and

data stored in the program memory (Flash or

ROM) are protected against read-out piracy (in-

cluding a re-write protection). In Flash devices,

when this protection is removed by reprogram-

ming the Option Byte, the entire program memory

is first automatically erased and the device can be

reprogrammed.

Refer to the Option Byte description for more de-

tails.

4K

1000h

3FFFh

7FFFh

9FFFh

BFFFh

D7FFh

DFFFh

EFFFh

FFFFh

8K

10K

16K

24K

32K

48K

60K

DV FLASH

MEMORY SIZE

2 Kbytes

8 Kbytes 16 Kbytes 24 Kbytes 40 Kbytes 52 Kbytes

4 Kbytes

4 Kbytes

SECTOR 2

SECTOR 1

SECTOR 0

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