GC1115 Datasheet, PDF(57/80 Page) Texas Instruments – Crest Factor Reduction Processor

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GC1115 Datasheet, PDF (57/80 Pages) Texas Instruments – Crest Factor Reduction Processor

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GC1115

SLWS144 â FEBRUARY 2005

SNAP_B_CONTROL 0x70 (112) Type: Read/Write Value at RESET: 0x0000

The SNAP_B_CONTROL register controls the operation of Snapshot RAM A, including the selection of its data

source and the type of data being captured. When using Snapshot RAM A in histogram mode, the RAM must

first be cleared by writing a 0x0002 to SNAP_B_CONTROL. If the GC1115 is operating in two-channel mode,

Snapshot RAM A can monitor the samples of either Channel 0 or Channel 1. Snapshot RAM A will not begin a

capture or histogram until the SNAP_B_SYNC event occurs. SNAP_B_SYNC cannot be triggered by a periodic

TIMER event.

BITS

[1:0] Snapshot RAM A command:

2 Channel-channel data source:

[5:3] Snapshot RAM A data source:

[7:6] Snapshot RAM A operating mode:

[15:8] Reserved

DESCRIPTION

00 â DISABLE (ignore all other bits in word)

01 â ENABLE (observe all other bits)

1x â CLEAR_RAM (ignore all other bits)

0 = Channel 0

1 = Channel 1

001: input

010: after Stage 1

011: after Stage 2

100: after Stage 3

101: after Stage 4

00 = capture 1k samples

01 = histogram I samples

10 = histogram Q samples

11 = histo. mag2(I + jQ)

SNAP_B_STATUS 0x71 (113) Type: Read only Value at RESET: 0x0000

The SNAP_B_STATUS register can be read to determine the current status (state) of Snapshot RAM A. After

sending a 0x2 command (clear RAM) to SNAP_B_CONTROL, SNAP_B_STATUS can be polled to determine

when the RAM has been cleared. After a Snapshot RAM A capture completes, the microprocessor or DSP can

receive an interrupt by enabling bit 0 of INT_MASK. During histogram operation, if one or more Snapshot RAM A

histogram bins overflows its 32-bit count, bit 2 of INT_MAP will be set. If bit 2 of INT_MASK is set, a Snapshot

RAM A bin overflow will also generate an interrupt. Snapshot RAM A will not begin a capture or histogram until

the SNAP_B_SYNC event occurs. SNAP_B_SYNC cannot be triggered by a periodic TIMER event.

BITS

[2:0]

[15:3]

Snapshot RAM A

status:

Reserved

000 â OFF

DESCRIPTION

001 â enabled (waiting)

010 â active (capturing) 011 â capture complete

100 â resetting (clearing all snapshot RAM bins)

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