Serial Communications Controllers
Data
NRZ
NRZI Mark
NRZI Space
FM0
FM1
Manchester
Differential
Manchester
If the DPLL is not needed, NRZ or NRZI codings can be selected in GSMR_L[RENC, TENC]. Coding
definitions are shown in
Coding
NRZ
A one is represented by a high level for the duration of the bit and a zero is represented by a low level.
NRZI Mark A one is represented by no transition at all. A zero is represented by a transition at the beginning of the
bit (the level present in the preceding bit is reversed).
NRZI
A one is represented by a transition at the beginning of the bit (the level present in the preceding bit is
Space
reversed). A zero is represented by no transition at all.
FM0
A one is represented by a transition only at the beginning of the bit. A zero is represented by a transition
at the beginning of the bit and another transition at the center of the bit.
FM1
A one is represented by a transition at the beginning of the bit and another transition at the center of the
bit. A zero is represented by a transition only at the beginning of the bit.
Manchester A one is represented by a high-to-low transition at the center of the bit. A zero is represented by a low to
high transition at the center of the bit. In both cases there may be a transition at the beginning of the bit
to set up the level required to make the correct center transition.
Differential
A one is represented by a transition at the center of the bit with the opposite direction from the transition
Manchester
at the center of the preceding bit. A zero is represented by a transition at the center of the bit with the
same polarity from the transition at the center of the preceding bit.
21-24
0
1
Figure 21-15. DPLL Encoding Examples
Table
21-9.
Table 21-9. DPLL Codings
MPC885 PowerQUICC Family Reference Manual, Rev. 2
1
0
Description
0
1
Freescale Semiconductor