ADE9078 datasheet(69/108 Pages) AD

69 / 108 page

ADE9078

Data Sheet

Rev. 0 | Page 68 of 107

There are 256 (2048/8) sample sets that can be stored in the

buffer. In the ADE9078, the sinc4 outputs at 16 kSPS so the

buffer can contain (256/16,000) = 16 ms of data from the sinc4

filter. The sinc4 + IIR LPF samples and DSP processed xI_PCF

and xV_PCF waveform samples are filled at 4 kHz, and the

buffer can contain 64 ms (256/4000) of this data.

When used with fixed data rate samples, the waveform buffer is

divided into 16 pages, Page 0 to Page 15. Each page contains 128

32-bit memory locations. Figure 108 illustrates this arrangement.

PAGE 15

0x800

0x880

0x87F

0x900

0x8FF

0x980

0x97F

0x9FF

0xFFF

0xF80

0xF7F

0xF00

0xEFF

PAGE 14

PAGE 3

PAGE 2

PAGE 1

PAGE 0

Figure 108. Waveform Buffer Page Arrangement—for Fixed Data Rate

Samples Only

Waveform Buffer Filling Indication—Fixed Data Rate

Samples

The WFB_PG_IRQEN register allows the user to monitor if

specific pages are filled, with one bit available per page. For

example, if Bit 0 and Bit 3 of WFB_PG_IRQEN is set, the user

receives an indication when Address 0x87F has been written,

when Page 0 is full, and when Address 0x9FF has been written,

meaning that Page 3 is full. The PAGE_FULL bit of the STATUS0

when the PAGE_FULL bit is set by setting the PAGE_FULL bit in

the STATUS0 register.

The WFB_LAST_PAGE bits in the WFB_TRG_STAT register

indicate which page was filled last when filling with fixed data

rate samples.

FIXED DATA RATE WAVEFORMS FILLING AND

TRIGGER-BASED MODES

The waveform buffer offers the following different filling modes

to be used with fixed data rate samples:



Stop when buffer is full



Continuous filling

The ADE9078 allows a selection of events to trigger waveform

buffer captures and there is an option to store the current waveform

buffer address during an event to allow the user to synchronize

the event with the waveform samples. The following waveform

buffer actions can be associated with an event when the buffer

is filling continuously:



Stop filling on trigger



Center capture around trigger



Save the event address and keep filling

Stop When Buffer Is Full Mode

The stop when buffer is full mode is enabled when WF_CAP_

SEL = 1 and the WF_MODE bits = 0 in the WFB_CFG register.

Set the WF_CAP_EN bit in the WFB_CFG register to start

filling the buffer from Address 0x800.

After Address 0xFFF in Page 15 is written, the filling operation

stops. To receive an indication when the buffer is full, set Bit 15

of the WFB_PG_IRQEN register prior to starting the capture.

Then, the PAGE_FULL bit in STATUS0 is set when the buffer is

full. This PAGE_FULL status change can be enabled to generate

an interrupt on IRQ0 as well.

To perform the next filling operation, disable the waveform

buffer by clearing bit WF_CAP_EN of the WFB_CFG register

to 0, and enable it again by setting the same bit to 1.

Continuous Fill Mode

Continuous fill mode is enabled when WF_CAP_SEL = 1 and

WF_MODE in the WFB_CFG register is equal to 1, 2, or 3.

Write the WF_CAP_EN bit in the WFB_CFG register to start

filling the buffer from Address 0x800.

In this mode, the waveform buffer is filled continuously. After

the entire buffer is filled up to Address 0xFFF, the filling

continues from Address 0x800 in a circular fashion.

In this mode, it is important to monitor the filling status of the

buffer using WFB_PG_IRQEN register in conjunction with the

PAGE_FULL bit in the STATUS0 register and WFB_LAST_PAGE

bits in the WFB_TRG_STAT register, as described in the

Waveform Buffer Filling Indication—Fixed Data Rate Samples

section. If the data is not read out of the buffer soon enough, it

is overwritten.

To restart the filling operation, disable the waveform buffer by

clearing the WF_CAP_EN bit of the WFB_CFG register, and

then enable it again by setting this bit.

It is recommended to read the WFB_LAST_PAGE register before

stopping the waveform buffer capture by clearing WF_CAP_EN

so that the page that contains the most recent valid data is known.

There are two variations on the continuous fill mode that stop

filling the waveform buffer based on a trigger event: stop filling

on trigger and center capture around trigger modes. These modes

are selected when WF_MODE = 1 and 2, respectively (see the

Stop Filling on Trigger and Center Capture Around Trigger

sections for more information).

ADE9078 数据表(PDF) 69 Page - Analog Devices

ADE9078 数据表(HTML) 69 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

数据表下载