ADUC834 Analog Devices, ADUC834 Datasheet - Page 31

• Manufacturer Part Number: ADUC834
• Description: Precision Analog Microcontroller: 1MIPS 8052 MCU + 62kB Flash + 16/24-Bit ADC + 12-Bit DAC
• Manufacturer: Analog Devices

Specifications of ADUC834

• Mcu Core: 8052
• Mcu Speed (mips): 1
• Sram (bytes): 2304Bytes
• Gpio Pins: 34
• Adc # Channels: 4
• Other: PWM

Alternatively ULOAD Mode can be used to save data to the
56 Kbytes of Flash/EE memory. This can be extremely useful in
datalogging applications where the ADuC834 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 accidently erased or repro-
grammed 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 recom-
mended to ensure that the bootloader always executes 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 Application Note uC007.
REV. A
62 KBYTES
PERMANENTLY EMBEDDED FIRMWARE ALLOWS CODE
ON-CHIP PROGRAM MEMORY. THE KERNEL PROGRAM
MEMORY
OF USER
TO BE DOWNLOADED TO ANY OF THE 62 KBYTES OF
APPEARS AS ‘NOP’ INSTRUCTIONS TO USER CODE.
CODE
Figure 19. Flash/EE Program Memory Map in
ULOAD Mode
EMBEDDED DOWNLOAD/DEBUG KERNEL
EITHER THE DOWNLOAD/DEBUG KERNEL
OR USER CODE (IN ULOAD MODE) CAN
DOWNLOAD/DEBUG MODE VIA THE
KERNEL BUT IS READ ONLY WHEN
THE USER BOOTLOADER SPACE
USER BOOTLOADER SPACE
USER DOWNLOAD SPACE
CAN BE PROGRAMMED IN
PROGRAM THIS SPACE.
EXECUTING USER CODE
56 KBYTE
6 KBYTE
2 KBYTE
DFFFH
F7FFH
FFFFH
E000H
F800H
0000H
–31–
Flash/EE Program Memory Security
The ADuC834 facilitates three modes of Flash/EE program
memory security. These modes can be independently activated,
restricting access to the internal code space. These security
modes can be enabled as part of serial download protocol, as
described in Application Note uC004, or via parallel program-
ming. The ADuC834 offers the following security modes:
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 are still allowed. This mode is deactivated
by initiating an “erase code and data” command in Serial Down-
load or Parallel Programming modes.
Secure Mode
This mode locks the code memory, disabling parallel program-
ming of the program memory. Reading/Verifying the memory in
Parallel Mode and reading the internal memory via a MOVC
command from external memory is also disabled. This mode is
deactivated by initiating an “erase code and data” 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
deasserted 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 an “erase
code and data” command in parallel programming mode.
ADuC834