Analog Devices ADSP-21261 SHARC Hardware Reference Manual page 405

Serial Ports
Clock Rising Edge Select. bit 12 ( ). This bit selects whether
SPCTLx CKRE
the serial port uses the rising edge (if set, = 1) or falling edge (if cleared,
= 0) of the clock signal for sampling data and the frame sync. This bit
applies to DSP Standard Serial and Multichannel modes only.
Frame Sync Required Select. bits 13 ( ). This bit selects
SPCTLx FSR
whether the serial port requires (if set, = 1) or does not require (if cleared,
= 0) a transfer frame sync. See "Frame Sync Options" on page 9-34 for
more details. This bit applies to DSP Standard Serial mode only.
Internal Frame Sync Select. bit 14 ( ). This bit selects whether
SPCTLx IFS
the serial port uses an internally-generated frame sync (if set, = 1) or a
frame sync from an external (if cleared, = 0) source. This bit is used for
Standard DSP Serial mode only.
Low Active Frame Sync Select. bit 16 ( ). This bit selects the
SPCTLx LFS
logic level of the (transmit or receive) frame sync signals. This bit selects
an active low frame sync (if set, = 1) or active high frame sync (if cleared,
= 0). Active high (0) is the default. This bit applies to DSP Standard Serial
mode only.
Late Transmit Frame Sync Select. bit 17 ( ). This bit selects
SPCTLx LAFS
when to generate the frame sync signal. This bit selects a late frame sync if
set (= 1) during the first bit of each data word. This bit selects an early
frame sync if cleared (= 0) during the serial clock cycle immediately pre-
ceding the first data bit. See "Frame Sync Options" on page 9-34 for more
details.
This bit applies to DSP Standard Serial mode. This bit is also used to
2
select between I S and Left-justified Sample Pair modes. See Table 9-1 on
page 9-10 and "Standard DSP Serial Mode" on page 9-11 for more
information.
Serial Port DMA Enable. bits 18 and 20 ( and ).
SPCTLx SDEN_A SDEN_B
This bit enables (if set, = 1) or disables (if cleared, = 0) the serial port's
channel DMA. Bits 18 and 20 apply to all operating modes.
ADSP-2126x SHARC Processor Hardware Reference 9-55