ADE9078ACPZ datasheet(70/108 Pages) AD

70 / 108 page

Data Sheet

ADE9078

Rev. 0 | Page 69 of 107

Stop Filling on Trigger

When WF_CAP_SEL = 1 and WF_MODE = 1, stop filling on

trigger mode is selected. It is recommended to use this mode to

analyze the ADC samples leading up to an event of interest.

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. The events

listed in Table 28 are classified as trigger events. Upon receiving

an enabled trigger event, the ADE9078 stops filling the

waveform buffer.

The events listed in Table 28 can be enabled as waveform buffer

triggers in the WFB_TRG_CFG register.

Table 28. Waveform Buffer Trigger Events in the

WFB_TRG_CFG Register

Bit(s)

Bit Name

Comment

TRIG_FORCE

Set this bit to trigger an event to stop

the waveform buffer filling

ZXCOMB

ZX on combined signal from VA, VB, VC

ZXVC

ZX event in Phase C voltage

ZXVB

ZX event in Phase B voltage

ZXVA

ZX event in Phase A voltage

ZXIC

ZX event in Phase C current

ZXIB

ZX event in Phase B current

ZXIA

ZX event in Phase A current

[2:0]

Reserved

The trigger events in the WFB_TRG_CFG register, Bits[10:3]

correspond to interrupt events within the ADE9078 with the

exception of the TRIG_FORCE bit. The user can set the

TRIG_FORCE bit, Bit 10 in the WFB_TRG_CFG register, to

stop the filling the waveform buffer in this mode.

When one of the events configured in WFB_TRG_CFG occurs,

the WFB_TRIG bit is set in the STATUS0 register. This bit can

be configured to generate an interrupt on the IRQ0 pin.

After the filling of the buffer stops, the WFB_TRG_IRQ bit is

set in the STATUS0 register. WFB_TRG_IRQ can also be

configured to generate an interrupt on the IRQ0 pin. At this

time, the address of the IN waveform of the last sample set is

stored in the WFB_TRIG_ADDR bits of the WFB_TRG_STAT

sample sets with addresses greater than the WFB_TRIG_ADDR

To ensure that a buffer’s worth of samples are captured before

the event, follow this sequence:

1. Select stop capture on trigger mode by setting

WF_CAP_SEL = 1 and WF_MODE = 1.

2. Disable all trigger events by writing WFB_TRG_CFG = 0.

3. Ensure that the buffer is filled one time by enabling an

interrupt to occur on IRQ0 when the last page is filled by

setting only Bit 15 in the WFB_PG_IRQEN register and

enabling the PAGE_FULL bit in the STATUS0 register.

Alternatively, read the LAST_PAGE register instead of

using the interrupt.

4. Start the capture by writing WF_CAP_EN = 1.

5. Wait for the buffer to be filled, indicated by when the

PAGE_FULL interrupt occurs or LAST_PAGE = 15.

6. Then, enable the desired waveform buffer events in the

WFB_TRG_CFG register and set the WFB_TRIG_IRQ bit

in STATUS0 to generate an interrupt when the event has

occurred and the waveform buffer has stopped filling.

7. When the WFB_TRIG_IRQ occurs, read WFB_TRIG_ADDR

to see the address of the trigger event, which is within a

sample or two of when the event occurred and is the last

filled address.

Waveform buffer values are retained when the waveform buffer

is disabled by clearing WF_CAP_EN in the WFB_CFG register;

however WFB_LAST_PAGE and WFB_TRIG_ADDR are reset

when that bit is cleared. Read the WFB_LAST_PAGE and

WFB_TRIG_ ADDR bits before writing WF_CAP_EN = 0.

Trigger events given in Table 28 must be enabled or disabled

before enabling the waveform buffer by writing to the

WFB_TRG_CFG register.

To perform the next filling operation in the stop filling on trigger

mode, disable the waveform buffer by clearing the WF_CAP_

EN bit of the WFB_CFG and then enable it again by setting the

same bit to 1. Note that if the TRIG_FORCE bit was set to force

a trigger that it must be cleared in the WFB_TRG_CFG register

before starting the next capture (before writing WF_CAP_EN = 1).

Center Capture Around Trigger

The center capture around trigger mode is enabled when

WF_CAP_SEL = 1 and WF_MODE = 2 and is similar to the

stop on trigger, except that the waveform buffer does not stop

filling after the trigger event. Even after the occurrence of the

trigger event, the filling of the buffer continues to occur for the

next 1024 32-bit memory locations before stopping. It is

recommended to use this mode to analyze samples before and

after an event. See the Stop Filling on Trigger section for more

information about trigger events.

Note that in the center trigger mode, the WFB_TRIG bit in

STATUS0 is set when the enabled trigger event occurs while the

WFB_TRG_IRQ bit in STATUS0 is set when the 1024 additional

memory locations are filled and the waveform buffer filling stops.

Both of these status bits can be configured to generate an

interrupt on the IRQ0 pin. Calculate the last filled address,

using WFB_TRIG_ADDR, as follows:

Last Filled Address = WFB_TRIG_ADDR − 1024

where WFB_TRIG_ADDR +1024 > 0xFFF.

Last Filled Address = WFB_TRIG_ADDR + 1024

where WFB_TRIG_ADDR + 1024 ≤ 0xFFF.

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