ADUC831BCP datasheet(28/76 Pages) AD

28 / 76 page

REV. 0

–28–

ADuC831

Using the Flash/EE Program Memory

The 62 kByte Flash/EE program memory array is mapped into the

lower 62 kBytes of the 64 kBytes program space addressable by

the ADuC831, and is used to hold user code in typical applications.

The program memory Flash/EE memory arrays can be programmed

in three ways:

(1) Serial Downloading (In-Circuit Programming)

The ADuC831 facilitates code download via the standard

UART serial port. The ADuC831 will enter serial download

mode after a reset or power cycle if the

PSEN pin is pulled low

through an external 1 k

resistor. Once in serial download

mode, the user can download code to the full 62 kBytes of

Flash/EE program memory while the device is in circuit in its

target application hardware.

A PC serial download executable is provided as part of the ADuC831

QuickStart development system. The Serial Download protocol

is detailed in a MicroConverter Applications Note uC004.

(2) Parallel Programming

The parallel programming mode is fully compatible with con-

ventional third party Flash or EEPROM device programmers.

In this mode Ports P0, P1, and P2 operate as the external data

and address bus interface, ALE operates as the Write Enable

strobe, and Port P3 is used as a general configuration port that

configures the device for various program and erase operations

during parallel programming. The high voltage (12 V) supply

required for Flash programming is generated using on-chip charge

pumps to supply the high voltage program lines.

The complete parallel programming specification is available on the

MicroConverter home page at www.analog.com/microconverter.

(3) User Download Mode (ULOAD)

In Figure 19 we can see that it was possible to use the 62 kBytes

of Flash/EE program memory available to the user as one single

block of memory. In this mode all of the Flash/EE memory is

read-only to user code.

However, the Flash/EE program memory can also be written to

during runtime simply by entering ULOAD mode. In ULOAD

mode the lower 56 kBytes of program memory can be erased

and reprogrammed by user software as shown in Figure 19.

ULOAD mode can be used to upgrade your code in the field via

any user defined download protocol. Configuring the SPI port

on the ADuC831 as a slave, it is possible to completely repro-

gram the 56 kBytes of Flash/EE program memory in only

5 seconds (see uC007).

Alternatively, ULOAD mode can be used to save data to the

56 kBytes of Flash/EE memory. This can be extremely useful in

data logging applications where the ADuC831 can provide up

to 60 kBytes of NV data memory on chip (4 kBytes of dedicated

Flash/EE data memory also exist).

The upper 6 kBytes of the 62 kBytes of Flash/EE program

memory is only programmable via serial download or parallel

programming. This means that this space appears as read only

to user code. Therefore, it cannot be accidentally erased or

reprogrammed by erroneous code execution. This makes it very

suitable to use the 6 kBytes as a bootloader. A Bootload Enable

option exists in the serial downloader to “Always RUN from E000h

after Reset.” If using a bootloader, this option is recommended

to ensure that the bootloader always executes the correct code

after reset.

Programming the Flash/EE program memory via ULOAD

mode is described in more detail in the description of ECON

and also in technical note uC007.

FFFFH

E000H

DFFFH

0000H

USER BOOTLOADER SPACE

THE USER BOOTLOADER SPACE

CAN BE PROGRAMMED IN

DOWNLOAD/DEBUG MODE VIA THE

KERNEL BUT IS READ ONLY WHEN

EXECUTING USER CODE

6 kBYTE

F800H

F7FFH

USER DOWNLOAD SPACE

EITHER THE DOWNLOAD/DEBUG

KERNEL OR USER CODE (IN

ULOAD MODE) CAN PROGRAM

THIS SPACE.

EMBEDDED DOWNLOAD/DEBUG KERNEL

PERMANENTLY EMBEDDED FIRMWARE ALLOWS

CODE TO BE DOWNLOADED TO ANY OF THE

62 kBYTES OF ON-CHIP PROGRAM MEMORY. THE

KERNEL PROGRAM APPEARS AS 'NOP' INSTRUC-

TIONS TO USER CODE.

56 kBYTE

2 kBYTE

62 kBYTES

OF USER

CODE

MEMORY

Figure 19. Flash/EE Program Memory Map in

ULOAD Mode

Flash/EE Program Memory Security

The ADuC831 facilitates three modes of Flash/EE program

memory security. These modes can be independently acti-

vated, restricting access to the internal code space. These

security modes can be enabled as part of serial download

protocol as described in technical note uC004 or via parallel

programming. The security modes available on the ADuC831

are described as follows:

Lock Mode

This mode locks the code memory, disabling parallel program-

ming of the program memory. However, reading the memory in

parallel mode and reading the memory via a MOVC command

from external memory is still allowed. This mode is deactivated

by initiating a code-erase command in serial download or parallel

programming modes.

Secure Mode

This mode locks code in memory, disabling parallel programming

(program and verify/read commands) as well as disabling the

execution of a ‘MOVC’ instruction from external memory, which

is attempting to read the op codes from internal memory. Read/

Write of internal data Flash/EE from external memory is also

disabled. This mode is deactivated by initiating a code-erase

command in serial download or parallel programming modes.

Serial Safe Mode

This mode disables serial download capability on the device. If

Serial Safe mode is activated and an attempt is made to reset

the part into serial download mode, i.e., RESET asserted and

de-asserted with

PSEN low, the part will interpret the serial

download reset as a normal reset only. It will therefore not enter

serial download mode but only execute a normal reset sequence.

Serial Safe mode can only be disabled by initiating a code-erase

command in parallel programming mode.

ADUC831BCP Datasheet(PDF) 28 Page - Analog Devices

ADUC831BCP Datasheet(HTML) 28 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76

Datasheet Download

Link URL