Digital Audio Interface (EBU)
MOTOROLA
Audio Functions
17-19
17.3.2.2
IEC958 Transmitter Exception Conditions
There are three transmitter exception conditions:
1. Transmit FIFO underrun
2. Transmit FIFO overrun
3. Transmit FIFO empty
17.3.2.3
IEC958-3 Ed2 and Tech 3250-E Standards Compliance
The IEC958 transmitter is compliant with IEC958-3 Ed2 and Tech 3250-E documents from international
IEC standards committee and European Broadcasting Union organizations.
The IEC958 transmitter implementation allows any sample frequency. Operation is guaranteed up to a
maximum incoming transmit clock of 1/3 of the 48 MHz system clock. The mark/space ratio of the transmit
clock must be equal to or better than 38/62.
Table 17-18 EBU1TxCChannel Registers Addresses
ADDRESS
NAME
WIDTH
DESCRIPTION
RESET
VALUE
ACCESS
MBAR2 + 0x28
EBU1TxC
Channel1
32
“C” channel bit settings for IEC958
transmitter - Consumer format
Undefined
RW
MBAR2 + 0x2C
EBU1TxC
Channel2
32
“C” channel bit settings for IEC958
transmitter - Professional format
Undefined
RW
Table 17-19 Formatting of EBUOUT1 (Consumer “C” channel)
IEC958 BITS
FIELD
NAME
DESCRIPTION
TAKEN FROM,
0:31
CONTROL
Relevant data
EBU1TXCCHANNEL1(31:0)
32:191
always 0
Note:
1. Ordering of bits in Ebu1TxCChannel1 is MSB sent out first. So, Ebu1TxCChannel1(31) is sent out as IEC958 bit 0.
Table 17-20 Formatting of EBUOUT2 - Professional “C” Channel
IEC958
BITS
FIELD
NAME
DESCRIPTION
TAKEN FROM,
0:23
CONTRO
L
Relevant data
EBU1TxCChannel2(31:8)
24:183
always 0
184:191
CRC using polynomial
x**8+x**4+x**3+x**2+1
EBU1TxCChannel2(7:0)
Note:
1. Ordering of bits in EBU1TxCChannel2 is MSB out first. So, EBU1TxCChannel2(31) is sent out as IEC958 bit 0.
Note:
2. IEC958 bits 184:191 are copied from EBU1TxCChannel2(7:0). For compliancy to EBU Tech 3250 document, the bits
184:191 should be filled in as the CRC of the complete C-channel frame. This is not done in hardware. A software
routine should be used to make sure EBU1TxCChannel2(7:0) reflects the correct value.
Note:
3. The EbuOut2 signal is only used on the 160 MAPBGA package.
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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