Transmit Path - Analog Devices SHARC ADSP-214 Series Hardware Reference Manual

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Functional Description

companding algorithms, A-law and μ-law, performed according to the

CCITT G.711 specification. The type of companding can be selected

independently for each SPORT. Companding is selected by the

field of the

Companding is supported on the A channel only. SPORT0, 2, 4

and 6 primary channels are capable of compression, while SPORTs

1, 3, 5 and 7 primary channels are capable of expansion.

In multichannel mode, when compression and expansion is

enabled, the number of channels must be programmed via the

writing to transmit buffer.

When companding is enabled, the data in the

right-justified, sign-extended expanded value of the eight received LSBs. A

the width of the transmit word) before it is transmitted. If the 32-bit value

is greater than the 13-bit A-law or 14-bit μ-law maximum, it is automati-

cally compressed to the maximum value.

Transmit Path

If the serial port is configured as a serial transmitter, the data transmitted

is written to the

panded in hardware on the primary A channel (SPORT 0, 2, 4 and 6

only), then automatically transferred to the transmit shift register, because

companding is not supported on the secondary B channels. The data in

the shift register is then shifted out via the SPORT's

signal, synchronous to the

are used, the

transmission.

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control register.

registers before writing to the transmit buffer.

registers should also be written before

compresses the 32-bit value to eight LSBs (zero-filled to

buffer. The data is (optionally) com-

signal indicates the start of the serial word

ADSP-214xx SHARC Processor Hardware Reference

buffers is the

clock. If framing signals

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