ade7566 Analog Devices, Inc., ade7566 Datasheet - Page 94

• Manufacturer Part Number: ade7566
• Description: Single-phase Energy Measurement Ic With 8052 Mcu, Rtc, And Lcd Driver
• Manufacturer: Analog Devices, Inc.

ADE7566/ADE7569
FLASH MEMORY
OVERVIEW
Flash memory is a type of nonvolatile memory that is in-circuit
programmable. The default state of a byte of flash memory is 0xFF
(erased). 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. However, a byte of flash
memory cannot be erased individually. The entire segment, or
page, of flash memory that contains the byte must be erased.
The ADE7566/ADE7569 provide 16 kB of flash program/
information memory. This memory is segmented into 32 pages
of 512 bytes each. Therefore, to reprogram 1 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 ADE7566/ADE7569 flash
memory controller also offers configurable flash memory
protection.
The 16 kB of flash memory are provided on-chip to facilitate
code execution without any external discrete ROM device
requirements. The program memory can be programmed in-
circuit, using the serial download or emulation options
provided or using conventional third party memory
programmers.
Flash/EE Memory Reliability
The flash memory arrays on the ADE7566/ADE7569 are fully
qualified for two key Flash/EE memory characteristics:
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.
1.
2.
3.
4.
Initial page erase sequence.
Read/verify sequence.
Byte program sequence.
Second read/verify sequence.
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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 the Specifications section, the ADE7566/ADE7569
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, and +85°C. The
results allow the specification of a minimum endurance 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 JEDEC Standard 22 Method
A117 at a specific junction temperature (T
qualification procedure, the flash memory is cycled to its
specified endurance limit before data retention is characterized.
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 eV,
derates with T
300
250
200
150
100
50
0
40
J
Figure 86. Flash/EE Memory Data Retention
as shown in Figure 86.
50
T
J
60
JUNCTION TEMPERATURE (°C)
ANALOG DEVICES
100 YEARS MIN.
SPECIFICATION
AT T
70
J
= 55 ° C
80
J
= 55°C). As part of this
90
100
110