ADE7569ASTZF16-RL Analog Devices Inc, ADE7569ASTZF16-RL Datasheet - Page 110

• Manufacturer Part Number: ADE7569ASTZF16-RL
• Description: IC,Power Metering,QFP,64PIN,PLASTIC
• Manufacturer: Analog Devices Inc

Specifications of ADE7569ASTZF16-RL

• Applications: Energy Measurement
• Core Processor: 8052
• Program Memory Type: FLASH (16 kB)
• Controller Series: ADE75xx
• Ram Size: 512 x 8
• Interface: I²C, SPI, UART
• Number Of I /o: 20
• Voltage - Supply: 3.135 V ~ 3.465 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 64-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

ADE7566/ADE7569
READ AND WRITE OPERATIONS
Writing to the RTC Registers
The RTC circuitry runs off a 32.768 kHz clock. The timekeeping
registers, Hundredths of a Second Counter SFR (HTHSEC,
0xA2), Seconds Counter SFR (SEC, 0xA3), Minutes Counter
SFR (MIN, 0xA4), and Hours Counter SFR (HOUR, 0xA5)
are updated with a 32.768 kHz clock. However, the RTC
Configuration SFR (TIMECON, 0xA1) and Alarm Interval SFR
(INTVAL, 0xA6) are updated with a 128 Hz clock. It takes up to
two 128 Hz clock cycles from when the MCU writes to the RTC
Configuration SFR (TIMECON, 0xA1) or Alarm Interval SFR
(INTVAL, 0xA6) until it is successfully updated in the RTC.
To protect the RTC timekeeping registers from runaway code, a
key must be written to the Key SFR (KYREG, 0xC1) to obtain
write access to the HTHSEC, SEC, MIN and HOUR SFRs. The
Key SFR (KYREG, 0xC1) should be set to 0xEA to unlock the
timekeeping registers and resets to 0 after a timekeeping register
is written to. The RTC registers can be written using the
following 8052 assembly code:
UpdateRTC:
Reading the RTC Counter SFRs
The RTC cannot be stopped to read the current time because
stopping the RTC would introduce an error in its timekeeping.
So the RTC is read on the fly. Therefore, the counter registers
must be checked for overflow. This can be accomplished
through the following 8052 assembly code:
ReadAgain:
Bank 0
MOV RTCKey, #0EAh
CALL
…
MOV KYREG, RTCKey
MOV SEC, #30
MOV KYREG, RTCKey
MOV MIN, #05
MOV KYREG, RTCKey
MOV HOUR, #04
RET
MOV R0, HTHSEC
MOV R1, SEC
MOV R2, MIN
MOV R3, HOUR
MOV A,
CJNE
A, 00h, ReadAgain ; 00h is R0 in
HTHSEC
UpdateRTC
; using Bank 0
Rev. PrA | Page 110 of 136
RTC MODES
The RTC can be configured in a 24-hour mode or a 256-hour
mode. A midnight event is generated when the RTC hour
counter rolls over from 23 to 0 or 255 to 0, depending on
whether the TFH bit is set in the RTC Configuration SFR
(TIMECON, 0xA1). The midnight event sets the MIDNIGHT
flag in the RTC Configuration SFR (TIMECON, 0xA1) and a
pending RTC interrupt is created. The RTC midnight event
wakes the 8052 MCU core if the MCU is asleep in PSM2 when
the midnight event occurs.
In the 24-hour mode, the midnight event is generated once a
day at midnight. The 24-hour mode is useful for updating a
software calendar to keep track of the current day. The 256-hour
mode results in power savings during extended operation in
PSM2 because the MCU core wakes up less frequently.
RTC INTERRUPTS
The RTC midnight interrupt and alarm interrupt are enabled by
setting the ETI bit in the Interrupt Enable and Priority 2 SFR
(IEIP2, 0xA9). When a midnight or alarm event occurs, a
pending RTC interrupt is generated. If the RTC interrupt is
enabled, the program vectors to the RTC interrupt address and
the pending interrupt is cleared. If the RTC interrupt is
disabled, the RTC interrupt remains pending until the RTC
interrupt is enabled. The program then vectors to the RTC
interrupt address.
The MIDNIGHT flag and ALARM flag are set when the
midnight event and alarm event occur, respectively. The user
should manage these flags to keep track of which event caused
an RTC interrupt by servicing the event and clearing the
appropriate flag in the RTC interrupt servicing routine.
Note that if the ADE7566/ADE7569 are awakened by an RTC
event, either by the MIDNIGHT event or ALARM event, the
pending RTC interrupt must be serviced before the device can
go back to sleep again. The ADE7566/ADE7569 will keep
waking up until this interrupt has been serviced.
Interval Timer Alarm
The RTC can be used as an interval timer. When the interval
timer is enabled by setting the ITEN bit in the RTC Configuration
SFR (TIMECON, 0xA1), the interval timer clock source
selected by the ITS1 and ITS0 bits is passed through an 8-bit
counter. This counter increments on every interval timer clock
pulse until it is equal to the value in the Alarm Interval SFR
(INTVAL, 0xA6). Then, an alarm event is generated, setting the
ALARM flag and creating a pending RTC interrupt. If the SIT
bit in the RTC Configuration SFR (TIMECON, 0xA1) is
cleared, the 8-bit counter is also cleared and starts counting
again. If the SIT bit is set, the 8-bit counter is held in reset after
the alarm occurs.
Preliminary Technical Data