Kawasaki 80C152 User Manual
Page 51
KS152JB Universal Communications Controller
Technical Specifications
Kawasaki LSI USA, Inc.
Page 51 of 120 Ver. 0.9 KS152JB2
that the correct remainder is left. The remainder that is checked for is 001110100001111B (1D0F
Hex). If there is a mismatch, an error is generated. The user software has the option of enabling
this interrupt so the CPU is notified.
16-Bit CRC
EOF - The End Of Frame (EOF) indicates when the transmission is complete. The EOF is identi-
fied by the end flag. An end flag consists of the bit pattern 01111110, The EOF can also serve as
the BOF for the next frame.
3.3.3 DATA ENCODING
The transmission of data in SDLC mode is done via NRZI encoding as shown in Figure below.
NRZI encoding transmits data by changing the state of the output whenever a 0 is being transmit-
ted. Whenever a 1 is transmitted the state of the output remains the same as the previous bit and
remains valid for the entire bit time. When SDLC mode is selected it automatically enables the
NRZI encoding on the transmit line and NRZI decoding on the receive line. The Address and Info
bytes are transmitted LSB first. The Address and Info bytes are transmitted LSB first. The CRC is
transmitted MSB first.
3.3.4 BIT STUFFING/STRIPPING
In SDLC mode one of the primary rules of the protocol is that in any normal data transmission,
there will never be an occurrence of more than 5 consecutive 1s. The GSC takes care of this
housekeeping chore by automatically inserting a 0 after every occurrence of 5 consecutive 1s and
the receiver automatically removes a zero after receiving 5 consecutive 1s. All the necessary steps
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RECEIVED
BIT
0
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1
0
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NRZI
BIT
TIME