EVAL-ADUC836QS AD [Analog Devices], EVAL-ADUC836QS Datasheet - Page 31

• Manufacturer Part Number: EVAL-ADUC836QS
• Description: MicroConverter, Dual 16-Bit ADCs with Embedded 62 kB Flash MCU
• Manufacturer: AD [Analog Devices]

User Download Mode (ULOAD)
In Figure 17 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 fi eld via
any user defi ned download protocol. Confi guring the SPI port on
the ADuC836 as a slave, it is possible to completely re pro gram
the 56 Kbytes of Flash/EE program memory in only 5 seconds
(see Application Note 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 ADuC836 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 mem o ry
are only pro gram ma ble via serial download or parallel pro gram -
ming. This means that this space appears as read-only to user
code. Therefore, it cannot be accidently erased or re pro grammed
by erroneous code execution. This makes it very suit able to use
the 6 Kbytes as a bootloader. A Bootload En able op tion exists in
the serial downloader to “Always RUN from E000h after Reset.”
If using a bootloader, this option is rec om mend ed 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. 0
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 ADuC836 facilitates three modes of Flash/EE program memory
security. These modes can be independently ac ti vat ed, restrict-
ing 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 pro gram ming. The
ADuC836 offers the following security modes:
Lock Mode
This mode locks the code memory, disabling parallel pro gram -
ming of the program memory. However, reading the memory in
Parallel mode and reading the memory via a MOVC com mand
from external memory is still allowed. This mode is de ac ti vat ed
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 pro gram -
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
load 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.
low, the part will interpret the serial down-
ADuC836