ADE7569_15 datasheet(40/152 Pages) AD

40 / 152 page

ADE7116/ADE7156/ADE7166/ADE7169/ADE7566/ADE7569

Rev. B | Page 40 of

152

ENERGY MEASUREMENT

The ADE7116/ADE7156/ADE7166/ADE7169/ADE7566/

ADE7569 offer a fixed function, energy measurement, digital

processing core that provides all the information needed to

measure energy in single-phase energy meters. The part

provides two ways to access the energy measurements: direct

access through SFRs for time sensitive information and indirect

access through address and data SFRs for the majority of energy

measurements. The Irms, Vrms, interrupts, and waveform registers

are readily available through the SFRs, as shown in Table 31.

Other energy measurement information is mapped to a page of

memory that is accessed indirectly through the MADDPT,

MDATL, MDATM, and MDATH SFRs. The address and data

SFRs act as pointers to the energy measurement internal

registers.

ACCESS TO ENERGY MEASUREMENT SFRs

Access to the energy measurement SFRs is achieved by reading

or writing to the SFR addresses provided in Table 31. The

internal data for the MIRQx SFRs is latched byte by byte into

the SFR when the SFR is read.

The WAV1x, WAV2x, VRMSx, and IRMSx registers are all 3-byte

SFRs. The 24-bit data is latched into these SFRs when the high

byte is read. Reading the low or medium byte before the high

byte results in reading the data from the previous latched sample.

Sample code to read the VRMSx register is as follows:

MOV

R1, VRMSH

//latches data in VRMSH,

VRMSM, and VRMSL SFRs

MOV

R2, VRMSM

MOV

R3, VRMSL

ACCESS TO INTERNAL ENERGY MEASUREMENT

REGISTERS

Access to the internal energy measurement registers is achieved

by writing to the energy measurement pointer address SFR

(MADDPT, Address 0x91). This SFR selects the energy measure-

ment register to be accessed and determines whether a read or

a write is performed (see Table 30).

Table 30. Energy Measurement Pointer Address SFR

(MADDPT, Address 0x91)

Bit

Description

1 = write, 0 = read

[6:0]

Energy measurement internal register address

Writing to the Internal Energy Measurement Registers

When Bit 7 of the energy measurement pointer address SFR

(MADDPT, Address 0x91) is set, the content of the MDATx

SFRs (MDATL, MDATM, and MDATH) is transferred to the

internal energy measurement register designated by the address

in the MADDPT SFR. If the internal register is one byte long,

only the MDATL SFR content is copied to the internal register,

and the MDATM SFR and MDATH SFR contents are ignored.

The energy measurement core functions with an internal clock

of 4.096 MHz/5 or 819.2 kHz. Because the 8052 core functions

with another clock, 4.096 MHz∕2CD, synchronization between

the two clock environments when CD = 0 or 1 is an issue. When

data is written to the internal energy measurement registers, a

small wait period needs to be implemented before another read

or write to these registers can take place.

Sample code to write 0x0155 to the 2-byte SAGLVL register

located at Address 0x14 in the energy measurement memory

space is as follows:

MOV

MDATM,#01h

MOV

MDATL,#55h

MOV

MADDPT,#SAGLVL_W (Address 0x94)

MOV

A,#05h

DJNZ

ACC,$

;Next write or read to energy

measurement SFR can be done after

this.

Reading the Internal Energy Measurement Registers

When Bit 7 of the energy measurement pointer address SFR

(MADDPT, Address 0x91) is cleared, the content of the internal

energy measurement register designated by the address in

MADDPT is transferred to the MDATx SFRs. If the internal

updated with a new value, and the MDATM SFR and MDATH

SFR contents are reset to 0x00.

The energy measurement core functions with an internal clock

of 4.096 MHz/5 or 819.2 kHz. Because the 8052 core functions

with another clock, 4.096 MHz∕2CD, synchronization between

the two clock environments when CD = 0 or 1 is an issue. When

data is read from the internal energy measurement registers, a

small wait period needs to be implemented before the MDATx

SFRs are transferred to another SFR.

Sample code to read the peak voltage in the 2-byte VPKLVL

MOV

MADDPT,#VPKLVL_R (Address 0x16)

MOV

A,#05h

DJNZ

ACC,$

MOV

DPH,MDATM

MOV

DPL,MDATL

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