CC2510_15 Datasheet, PDF (162/245 Pages) Texas Instruments – Low-Power SoC (System-on-Chip) with MCU, Memory,2.4 GHz RF Transceiver, and USB Controller

CC2511F8 - Not Recommended for New Designs
CC2510Fx / CC2511Fx
Fs (kHz)
8
8
44.1
48
Word Size (W)
8
16
16
16
CLKDIV
101.5625
50.78125
9.21201
8.46354
I2SCLKF2
0x06
0x06
0x8A
0x06
I2SCLKF1
0x59
0x59
0x2F
0x59
I2SCLKF0
0x10
0x20
0x1B
0xC0
Exact
Yes
Yes
No
Yes
Table 58: Example I²S Clock Configurations (CC2510Fx, 26 MHz)
12.15.8.2 Word Size
The word size must be set before master
mode is enabled. The word size is the number
of bits used for each sample and can be set to
a value between 1 and 33. To set the word
size, write word size – 1 to the
I2SCFG1.WORDS[4:0] bits. Setting the word
size to a value of 17 or more causes the I²S to
pad each word with 0’s in the least significant
bits since the data registers provide maximum
16 bits. This feature allows samples to be sent
to an I²S device that takes a higher resolution
than 16 bits.
If the size of the received samples exceeds 16
bits, only the 16 most significant bits will be put
in the data registers and the remaining low
order bits will be discarded.
12.15.9 Slave Mode
The I²S is configured as a slave device by
setting I2SCFG0.MASTER to 0. When in slave
mode the SCK and WS signals are generated
by an external I²S master and are inputs to the
I²S interface.
12.15.9.1 Word Size
When the I²S operates in slave mode, the word
size is determined by the master that
generates the WS signal.
The I²S will provide bits from the internal 16-bit
buffer until the buffer is empty. If the buffer
becomes empty and the master still requests
more bits, the I²S will send 0’s (low order bits).
If more than 16 bits are being received, the low
order bits are discarded.
12.15.10 Mono
The I²S also supports mono audio samples.
To receive mono samples, I2SCFG0.RXMONO
should be set to 1. Words from the right
channel will then not be read into the data
registers. This feature is included because
some mono devices repeat their audio data in
both channels and the left channel is the
default mono channel.
To send mono samples, I2SCFG0.TXMONO
should be set to 1. Each word will then be
repeated in both channels before a new word
is fetched from the data registers. This is to
enable sending a mono audio signal to a
stereo audio sink device.
12.15.11 Word Counter
The I²S contains a 10-bit word counter, which
is counting transitions on the WS line. The
counter can be cleared by triggers or by writing
to the I2SWCNT register. When a trigger
occurs, or a value is written to I2SWCNT, the
current value of the word counter is copied into
the
I2SSTAT.WCNT[9:8]:I2SWCNT.WCNT[7:0]regi
sters and the word counter is cleared.
Three triggers can be used to copy/clear the
word counter.
• USB SOF: USB Start of Frame. Occurs
every ms (CC2511Fx only)
• T1_CH0: Timer 1, compare, channel 0
• IOC_1: IO pin input transition (P1_3)
Which trigger to use is configured through the
TRIGNUM field in the I2SCFG1 register. When
the I²S is configured not to use any trigger
(I2SCFG1.TRIGNUM=0), the word counter can
only be copied/cleared from software.
The word counter will saturate if it reaches its
maximum value. Software should configure the
trigger-interval and sample-rate to ensure this
never happens.
CC2511Fx: The word counter is typically used to
calculate the average sample rate over a long
period of time (e.g. 1 second) needed by
adaptive isochronous USB endpoints. The
USB SOF event must then be used as trigger.
12.15.12 µ-Law Compression and Expansion
The I²S interface can be configured to perform
μ-Law compression and expansion. µ-Law
compression is enabled by setting the
I2SCFG0.ULAWC bit to 1 and µ-Law
SWRS055G
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