HD64570 HITACHI [Hitachi Semiconductor], HD64570 Datasheet - Page 35

• Manufacturer Part Number: HD64570
• Description: Serial Communications Adaptor
• Manufacturer: HITACHI [Hitachi Semiconductor]

1.7.4
The SCA supports five transmission codes: NRZ, NRZI, FM0, FM1, and Manchester (figure 1.8).
See figures 5.39, 5.40, and 5.41 for the timing relationships between the TX and RX clocks and
each code.
FM
Enco-
ding
Type No. Code
NRZ
Enco-
ding
1
2
1
2
3
Transmission Codes
NRZ
(Nonreturn to
zero)
NRZI
(Nonreturn to
zero inversion)
FM0
(Frequency
modulation
space)
FM1
(Frequency
modulation
mark)
MANCHESTER
(Manchester)
Figure 1.8 Transmission Codes
0
1
Data and waveform
0
0
1
1
Rev. 0, 07/98, page 19 of 453
1: High
0: Low
1: No transition
0: Transition
1: Transition at
0: Transitions at
1: Transitions at
0: Transition at
1: High-to-low transition
0: Low-to-high transition
Definition of 1 and 0
beginning of bit cell
beginning and center
of bit cell
beginning and center
of bit cell
beginning of bit cell
at center of bit cell
at center of bit cell