Datasheet

Data Sheet ADE5166/ADE5169/ADE5566/ADE5569
Rev. D | Page 107 of 156
FLASH MEMORY
FLASH MEMORY OVERVIEW
Flash memory is a type of nonvolatile memory that is in-circuit
programmable. The default, erased state of a byte of flash memory
is 0xFF. When a byte of flash memory is programmed, the required
bits change from 1 to 0. The flash memory must be erased to turn
the 0s back to 1s. A byte of flash memory cannot, however, be
erased individually. The entire segment, or page, of flash
memory that contains the byte must be erased.
The ADE5166/ADE5169/ADE5566/ADE5569 provide 62 bytes
of flash program/information memory. This memory is segmented
into 124 pages that each contain 512 bytes. To reprogram one
byte of flash memory, the other 511 bytes in that page must be
erased. The flash memory can be erased by page or all at once in
a mass erase. There is a command to verify that a flash write
operation has completed successfully. The ADE5166/ADE5169/
ADE5566/ADE5569 flash memory controller also offers
configurable flash memory protection.
The 62 bytes of flash memory are provided on chip to facilitate
code execution without any external discrete ROM device require-
ments. The program memory can be programmed in circuit,
using the serial download mode provided or using conventional
third-party memory programmers.
Flash/EE Memory Reliability
The flash memory arrays on the ADE5166/ADE5169/ADE5566/
ADE5569 are fully qualified for two key Flash/EE memory cha-
racteristics: Flash/EE memory cycling endurance and Flash/EE
memory data retention.
Endurance quantifies the ability of the Flash/EE memory to be
cycled through many program, read, and erase cycles. In real
terms, a single endurance cycle is composed of four independent,
sequential events, as follows:
1. Initial page erase sequence
2. Read/verify sequence
3. Byte program sequence
4. Second read/verify sequence
In reliability qualification, every byte in both the program and
data Flash/EE memory is cycled from 0x00 to 0xFF until a first
fail is recorded, signifying the endurance limit of the on-chip
Flash/EE memory.
As indicated in Table 4, the ADE5166/ADE5169/ADE5566/
ADE5569 flash memory endurance qualification has been carried
out in accordance with JEDEC Standard 22 Method A117 over
the industrial temperature range of −40°C, +25°C, +85°C, and
+125°C. The results allow the specification of a minimum endur-
ance figure over supply and temperature of 100,000 cycles, with a
minimum endurance figure of 20,000 cycles of operation at 25°C.
Retention is the ability of the flash memory to retain its
programmed data over time. Again, the parts have been
qualified in accordance with the formal retention lifetime
specification, JEDEC Standard 22 Method A117, at a specific
junction temperature (T
J
= 55°C). As part of this qualification
procedure, the flash memory is cycled to its specified endurance
limit, as described previously, before data retention is charac-
terized. This means that the flash memory is guaranteed to retain
its data for its full specified retention lifetime every time the
flash memory is reprogrammed. It should also be noted that
retention lifetime, based on an activation energy of 0.6 e V,
derates with T
J
, as shown in Figure 92.
40 60 70 90
T
J
JUNCTION TEMPERATURE (°C)
RETENTION
(Years)
250
200
150
100
50
0
50 80 1
10
300
100
ANALOG DEVICES
SPECIFICATION
100 YEARS MIN.
AT T
J
= 55
° C
07411-067
Figure 92. Flash/EE Memory Data Retention
FLASH MEMORY ORGANIZATION
The ADE5166/ADE5169/ADE5566/ADE5569 contain a 64 kB
array of Flash/EE program memory. The upper 2 kB contain per-
manently embedded firmware, allowing in-circuit serial download,
serial debug, and nonintrusive single-pin emulation. The 2 kB
of embedded firmware also contain essential coefficients that
provide calibration to peripherals such as the ADCs and reference.
The embedded firmware contained in the upper 2 kB of
Flash/EE memory is not accessible by the user.
EMBEDDED DOWNLOAD/DEBUG KERNEL
PERMANENTLY EMBEDDED FIRMWARE ALLOWS
CODE TO BE DOWNLOADED TO ANY OF THE
62 kB OF ON-CHIP PROGRAM MEMORY.
THE KERNEL PROGRAM APPEARS AS NOP
INSTRUCTIONS TO USER CODE.
62 kB OF FLASH/EE PROGRAM MEMORY
ARE AVAILABLE TO THE USER. ALL OF THIS
SPACE CAN BE PROGRAMMED FROM THE
PERMANENTLY EMBEDDED DOWNLOAD/DEBUG
KERNEL OR IN PARALLEL PROGRAMMING MODE.
USER PROGRAM MEMORY
0×FFFF
2kB
0×F800
0×F7FF
62kB
0×0000
07411-229
Figure 93. Flash Memory Organization