HD64570 Datasheet, PDF (33/469 Pages) Hitachi Semiconductor – Serial Communications Adaptor

Mark
Asynchronous
Start bit
Byte synchronous
Bisync
5 to 8 data bits
Parity Stop bit(s)
(even (1, 1.5, or 2 bits)
or odd)
Header
Information
(arbitrary number of 8 bit characters)
Block check
(CRC-16)^*1
DDCMP
Header
Count Flag Acknow- SequenceAddress CRC-1^*6¹
(14 bits) (2 bits) ^{ledge (8 bits)}(8 bits) (16 bits) (16 bits)
Information
(arbitrary number
of 8-bit characters)
CRC-16 ^*1
(16 bits)
Bit synchronous
LAPB
Flag Address Control
(8 bits) field field
01111110 (8 bits) (8 bits)
LAPD
Flag _EA
(8 bits) CR
011111100
SAPI ^EA
(6 bits)
1
TEI
(7 bits)
SOH: Start of header
STX: Start of text
SYN: Synchronous hold
Information field
(multiple of 8 bits)
Control
field (8 or
16 bits)
Information field
(multiple of 8 bits)
ETB: End of text block
ETX: End of text
Frame check _Flag
se(CqRueCn-cCeC(I1T_*6T₂bits)_{(8 bits)}
preset 1) 01111110
Frame check _Flag
se(CqRueCn-cCeC(I1T_*6T₂bits)_{(8 bits)}
preset 1) 01111110
Frame relay ^{8 bits}
8 bits
Flag _EA
(8 bits) CR
011111100
DLCI ^EA
(upper) ^DE
1
BECN
FECN
DLCI
(lower)
Information field
(multiple of 8 bits)
se(CFqRuraeCmn-ceCeCc(hI1Te_*6T₂^ckbits)_(8Flbaigts)
preset 1) 01111110
Notes: 1.
2.
8 bits
8 bits
SAPI: Service access point identifier
TEI: Terminal endpoint indicater
EA: Address field extention
CR: Command/response field
DLCI: Data link connection identifier
DE: Discard eligibility indicator
BECN: Backward (network to transmit
station) explicit congestion
notification
FECN: Forward (network to receive
station) explicit congestion
notification
CRC-16 polynomial: X¹⁶ + X¹⁵ + X² + 1
CRC-CCITT polynomial: X¹⁶ + X¹² + X⁵ + 1
Figure 1.7 Examples of Transmission Formats
Rev. 0, 07/98, page 17 of 453