3.1.27 Waveform Capture Control Register

Waveform capture of 32-bit samples may be accomplished through exercise of these control bits, to select the capture mode, which type of samples are to be captured and how many samples are captured. Capture data are written to the buffer starting at the address pointer stored in the CAPTURE_ADDR register. After each set of samples are captured, the number of the last sample set captured is stored in the CAPTURE_STATUS output register.

Upon completion of a one-shot capture sequence, the CAPTURE_STATE bits in the CAPTURE_STATUS register will be updated to COMPLETE, then, after the application code resets the CAPTURE_ENABLE bit to DISABLED, the CAPTURE_STATE bits will, then, be reset to DISABLED.

Name:	CAPTURE_CTRL
Property:	Read-Write


Bit	31	30	29	28	27	26	25	24
	CAPTURE_EN
Access	R/W
Reset	0


Bit	23	22	21	20	19	18	17	16

Access
Reset


Bit	15	14	13	12	11	10	9	8
		CH_SEL_IN	CH_SEL_VC	CH_SEL_IC	CH_SEL_VB	CH_SEL_IB	CH_SEL_VA	CH_SEL_IA
Access		R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset		0	0	0	0	0	0	0


Bit	7	6	5	4	3	2	1	0
		CAPTURE_SOURCE[2:0]					CAPTURE_TYPE[1:0]
Access		R/W	R/W	R/W			R/W	R/W
Reset		0	0	0			0	0

Bit 31 – CAPTURE_EN Enable Waveform Capture

Value	Description
0x0	Waveform capture is disabled
0x1	Waveform capture is enabled

Bits 8, 9, 10, 11, 12, 13, 14 – CH_SEL_x Capture Channel Select

Up to 7 channels of data may be captured at the same time. Only selected channels are captured.

Value	Description
0x0	Waveform capture is disabled for channel x
0x1	Waveform capture is enabled for channel x

Bits 6:4 – CAPTURE_SOURCE[2:0] Capture Source Select

All captured data is after Vref compensation was applied and are scaled values (normalized by the appropriate K_Ix and K_Vx). In the case of 16 kHz sampling data, the calibration constants were not applied.

Value	Description
0x0	Capture 16 kHz data [sQ1.30] before DSP filtering
0x1	Capture 4 kHz FBW data [sQ2.29] (Full Bandwidth = fundamental + harmonics)
0x2	Capture 4 kHz NBW data [sQ2.29] (Narrow Bandwidth = fundamental only)
0x3	Capture 8 kHz FBW data [sQ2.29] (Full Bandwidth = fundamental + harmonics)
Other	RESERVED

Bits 1:0 – CAPTURE_TYPE[1:0] Selects whether capture is one-shot in nature (no samples captured prior to being enabled) or continuous capturing.

Capture must be enabled to initiate a capture process. Once enabled, capture occurs based on the requested capture mode. If enabled and a continuous capture mode is selected, capture continues until it is disabled. If enabled and a one-shot capture mode is selected, capture continues until appointed number of samples is captured.

Value	Name	Description
0x0	One-Shot Capture Mode	Capture total CAPTURE_BUFF_SIZE of future data; capture will stop after capture finishes or is disabled.
0x1	Continuous Capture Mode	Continuous capture of waveform data in circular-buffer fashion; capture will stop immediately after capture is disabled. CAPTURE_OFFSET indicates the offset of latest sample in capture buffer.