
Frame Sync Options
9-34
ADSP-2126x SHARC Processor Hardware Reference
Frame Sync Options
Framing signals indicate the beginning of each serial word transfer. A vari-
ety of framing options are available on the SPORTs. The
SPORTx_FS
signals are independent and are separately configured in the Control
register.
Framed Versus Unframed Frame Syncs
The use of frame sync signals is optional in serial port communications.
The
FSR
(transmit frame sync required) control bit determines whether
frame sync signals are used. Active low or high frame syncs are selected
using the
LFS
bit. This bit is located in the
SPCTLx
control registers.
When
FSR
is set (=1), a frame sync signal is required for every data word.
To allow continuous transmission from the processor, each new data word
must be loaded into the transmit buffer before the previous word is shifted
out and transmitted.
When
FSR
is cleared (=0), the corresponding frame sync signal is not
required. A single frame sync is required to initiate communications but it
is ignored after the first bit is transferred. Data words are then transferred
continuously in what is referred to as an unframed mode.
When DMA is enabled in a mode where frame syncs are not required,
DMA requests may be held off by chaining or may not be serviced fre-
quently enough to guarantee continuous unframed data flow.
illustrates framed serial transfers.
Summary of Contents for ADSP-21261 SHARC
Page 30: ...Contents xxx ADSP 2126x SHARC Processor Hardware Reference ...
Page 40: ...Register Diagram Conventions xl ADSP 2126x SHARC Processor Hardware Reference ...
Page 58: ...Differences From Previous SHARCs 1 18 ADSP 2126x SHARC Processor Hardware Reference ...
Page 112: ...Secondary Processing Element PEy 2 54 ADSP 2126x SHARC Processor Hardware Reference ...
Page 178: ...Summary 3 66 ADSP 2126x SHARC Processor Hardware Reference ...
Page 204: ...DAG Instruction Summary 4 26 ADSP 2126x SHARC Processor Hardware Reference ...
Page 322: ...Setting Up DMA 7 32 ADSP 2126x SHARC Processor Hardware Reference ...
Page 436: ...SPORT Programming Examples 9 86 ADSP 2126x SHARC Processor Hardware Reference ...
Page 521: ...ADSP 2126x SHARC Processor Hardware Reference 11 31 Input Data Port rts IDP_ISR end ...
Page 522: ...Input Data Port Programming Example 11 32 ADSP 2126x SHARC Processor Hardware Reference ...
Page 590: ...Timer Programming Examples 14 20 ADSP 2126x SHARC Processor Hardware Reference ...
Page 796: ...I O Processor Registers A 174 ADSP 2126x SHARC Processor Hardware Reference ...
Page 800: ...B 4 ADSP 2126x SHARC Processor Core Manual ...
Page 846: ...Index I 36 ADSP 2126x SHARC Processor Hardware Reference ...