ADE7518ASTZF16-RL Analog Devices Inc, ADE7518ASTZF16-RL Datasheet - Page 100

• Manufacturer Part Number: ADE7518ASTZF16-RL
• Description: 1-Phase Energy Meter IC
• Manufacturer: Analog Devices Inc

Specifications of ADE7518ASTZF16-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

ADE7518
REAL-TIME CLOCK
The ADE7518 has an embedded real-time clock (RTC), as
shown in Figure 88. The external 32.768 kHz crystal is used as
the clock source for the RTC. Calibration is provided to
compensate the nominal crystal frequency and for variations in
the external crystal frequency over temperature. By default, the
RTC is maintained active in all power saving modes. The RTC
counters retain their values through watchdog resets and
external resets. They are only reset during a power-on reset.
CALIBRATED
32.768kHz
HUNDREDTHS COUNTER
INTERVAL COUNTER
SECONDS COUNTER
MINUTES COUNTER
HOURS COUNTER
PRESCALER
INTVAL SFR
32.768kHz
CRYSTAL
HTHSEC
HOUR
8-BIT
8-BIT
SEC
MIN
RTCEN
Figure 88. RTC Implementation
RTCCOMP
CALIBRATION
EQUAL?
TEMPCAL
MIDNIGHT EVENT
SELECTION
ITS1
INTERVAL
TIMEBASE
MUX
ITS0
ALARM
EVENT
ITEN
Rev. 0 | Page 100 of 128
RTC REGISTERS
Note that all the real-time clock SFRs are not bit addressable.
Table 108. Real-Time Clock SFR
SFR
TIMECON
HTHSEC
SEC
MIN
HOUR
INTVAL
RTCCOMP
TEMPCAL
Protecting the RTC from Runaway Code
To protect the RTC from runaway code, a key must be written
to the KYREG register to obtain write access to the Interrupt
Pins Configuration SFR (INTPR, 0xFF), Hundredths of a
Second Counter SFR (HTHSEC, 0xA2), Seconds Counter SFR
(SEC, 0xA3), Minutes Counter SFR (MIN, 0xA4), and Hours
Counter SFR (HOUR, 0xA5). KYREG should be set to 0xEA to
unlock it and reset it to zero after a timekeeping register is
written to. The RTC registers can be written using the following
8052 assembly code:
MOV
MOV
KYREG,#0EAh
INTPR,#080h
Address
0xA1
0xA2
0xA3
0xA4
0xA5
0xA6
0xF6
0xF7
Description
RTC Configuration (see Table 109).
Hundredths of a Second Counter
(see Table 110).
Seconds Counter (see Table 111).
Minutes Counter (see Table 112).
Hours Counter (see Table 113).
Alarm Interval (see Table 114).
RTC Nominal Compensation
(see Table 115).
RTC Temperature Compensation
(see Table 116).