SLOU186F
–
AUGUST 2006
–
REVISED AUGUST 2010
5.3.4
FIFO Control Registers
Table 5-26. FIFO Status (1Ch)
Low nibbles of complete bytes to be transferred through FIFO; Information about a broken byte and number of bits to be transferred from it
Bit
Bit Name
Function
Comments
B7
RFU
Set to LOW
Reserved for future use (RFU)
B6
Fhil
FIFO level HIGH
Indicates that 9 bytes are already in the FIFO (for RX)
B5
Flol
FIFO level LOW
Indicates that only 3 bytes are in the FIFO (for TX)
B4
Fove
FIFO overflow error
Too much data was written to the FIFO
B3
Fb3
FIFO bytes fb[3]
Bits B0:B3 indicate how many bytes that are loaded in FIFO were not read
out yet (displays N
–
1 number of bytes). If 8 bytes are in the FIFO, this
number is 7.
B2
Fb2
FIFO bytes fb[2]
B1
Fb1
FIFO bytes fb[1]
B0
Fb0
FIFO bytes fb[0]
Table 5-27. TX Length Byte1 (1Dh)
High 2 nibbles of complete bytes to be transferred through FIFO
Register default is set to 0x00 at POR and EN=0. It is also automatically reset at TX EOF
Bit
Bit Name
Function
Comments
B7
Txl11
Number of complete byte bn[11]
High nibble of complete bytes to be transmitted
B6
Txl10
Number of complete byte bn[10]
B5
Txl9
Number of complete byte bn[9]
B4
Txl8
Number of complete byte bn[8]
B3
Txl7
Number of complete byte bn[7]
Middle nibble of complete bytes to be transmitted
B2
Txl6
Number of complete byte bn[6]
B1
Txl5
Number of complete byte bn[5]
B0
Txl4
Number of complete byte bn[4]
Table 5-28. TX Length Byte2 (1Eh)
Low nibbles of complete bytes to be transferred through FIFO; Information about a broken byte and number of bits to be transferred from it
Register default is set to 0x00 at POR and EN=0. It is also automatically reset at TX EOF
Bit
Bit Name
Function
Comments
B7
Txl3
Number of complete byte bn[3]
Low nibble of complete bytes to be transmitted
B6
Txl2
Number of complete byte bn[2]
B5
Txl1
Number of complete byte bn[1]
B4
Txl0
Number of complete byte bn[0]
B3
Bb2
Broken byte number of bits bb[2]
Number of bits in the last broken byte to be transmitted.
B2
Bb1
Broken byte number of bits bb[1]
It is taken into account only when broken byte flag is set.
B1
Bb0
Broken byte number of bits bb[0]
B0
Bbf
Broken byte flag
If 1, indicates that last byte is not complete 8 bits wide.
Copyright
©
2006
–
2010, Texas Instruments Incorporated
System Description
33
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