13-8
MCF5272 User’s Manual
GCI/IDL Block
position of a byte, with the last bit received aligned in the msb position.
Because the presentation of HDLC encoded data on the physical interface is lsb first, the
lsb is right-aligned in the transmit and receive shift register.
A D-channel byte is formed by concatenating two D bits from each of four frames. This
data is also right-aligned in the D-channel receive register as shown in Figure 13-7.
Figure 13-7. D-Channel HDLC Encoded and Unencoded Data.
13.2.3.4 D-Channel Unencoded Data
As with the B channel, a mechanism is provided to support incoming D channels containing
unencoded data, even though as of this document’s publication date, no communication
protocols using unencoded D-channel data are known.
As with unencoded (PCM encoded) B-channel data, it is assumed unencoded D-channel
information is presented on the physical line msb first. The msb is left-aligned in the
transmit and receive shift register, that is, the first bit received is aligned in the msb position
through to the last received bit of a byte that is aligned in the lsb position.
A D-channel byte is formed by concatenating two D bits from each frame over four
consecutive frames as shown in Figure 13-7. These 8 bits are also left-aligned in the
D-channel receive register, that is, the first two D-channel bits from the first frame go into
the two msbs, B
7
and B
6
, the next two D-channel bits from the second frame in B
5
and B
4
,
and so on, until the last two D-channel bits in the fourth frame are aligned in B
1
and B
0
.
DCL
FSR
Din/Dout
D
0
D
1
Frame 0
Frame 1
Frame
3
2
1
0
D7
D6
D5
D4
D3
D2
D1
D0
D
2
D
3
D
4
D
5
D
6
D
7
Frame 2
Frame 3
Din/Dout
D
7
D
6
D
5
D
4
D
3
D
2
D
1
D
0
Unencoded
HDLC
Encoded
8-Bit D-Channel Receive/Transmit Register, RD, TD
Содержание DigitalDNA ColdFire MCF5272
Страница 1: ...MCF5272UM D Rev 0 02 2001 MCF5272 ColdFire Integrated Microprocessor User s Manual ...
Страница 38: ...xxxviii MCF5272 User s Manual TABLES Table Number Title Page Number ...
Страница 58: ...1 10 MCF5272 User s Manual MCF5272 Specific Features ...
Страница 90: ...2 42 MCF5272 User s Manual Exception Processing Overview ...
Страница 96: ...3 6 MCF5272 User s Manual MAC Instruction Execution Timings ...
Страница 158: ...5 46 MCF5272 User s Manual Motorola Recommended BDM Pinout ...
Страница 184: ...7 12 MCF5272 User s Manual Interrupt Controller Registers ...
Страница 338: ...13 44 MCF5272 User s Manual Application Examples ...
Страница 414: ...18 6 MCF5272 User s Manual PWM Programming Model ...
Страница 452: ...19 38 MCF5272 User s Manual Power Supply Pins ...
Страница 482: ...20 30 MCF5272 User s Manual Reset Operation ...
Страница 492: ...21 10 MCF5272 User s Manual Non IEEE 1149 1 Operation ...
Страница 548: ...INDEX Index 12 MCF5272 User s Manual ...