Chapter 13. Physical Layer Interface Controller (PLIC)
13-5
GCI/IDL Block
The CPU should service the B1 and B2 registers once every 500
µ
S. Overrun conditions
can be avoided only if the CPU services these registers in a timely manner.
The MCF5272 has 4 GCI/IDL interfaces. Thus the theoretical maximum is twelve 32-bit
data registers to be read. For most applications the typical number is less.
Figure 13-3 shows the shift register, shadow register, internal bus register, and multiplexor
for each B receive channel.
After reset, the B- and D-channel shift registers and shadow registers are initialized to all
ones.
Figure 13-3. GCI/IDL B-Channel Receive Data Register Demultiplexing
13.2.2 GCI/IDL B- and D-Channel Transmit Data Registers
Figure 13-4. GCI/IDL Transmit Data Flow
The maximum transmission rate for each GCI/IDL port is 144 Kbps: the sum of two
64-Kbps B channels and one 16-Kbps D-channel. Frames of B
1
, B
2
, and D-channels are
packed together in a similar way to the receive side.
8 bits
DEMUX
32 bits
Internal Bus
8-KHz Rate
Shift Register (B1 or B2)
2-KHz transfer and interrupt
8 bits
8 bits
8 bits
8 bits
Shadow Register
START
END
D
IN
64 Kbps
32
32
B1, B2, Receive
Data Register
B1
B2
D
B1 Shift Register
B2 Shift Register
D Shift Register
Dout
DCL
32
32
8
Internal Bus
Multiplexing
Circuitry
Summary of Contents for DigitalDNA ColdFire MCF5272
Page 1: ...MCF5272UM D Rev 0 02 2001 MCF5272 ColdFire Integrated Microprocessor User s Manual ...
Page 38: ...xxxviii MCF5272 User s Manual TABLES Table Number Title Page Number ...
Page 58: ...1 10 MCF5272 User s Manual MCF5272 Specific Features ...
Page 90: ...2 42 MCF5272 User s Manual Exception Processing Overview ...
Page 96: ...3 6 MCF5272 User s Manual MAC Instruction Execution Timings ...
Page 158: ...5 46 MCF5272 User s Manual Motorola Recommended BDM Pinout ...
Page 184: ...7 12 MCF5272 User s Manual Interrupt Controller Registers ...
Page 338: ...13 44 MCF5272 User s Manual Application Examples ...
Page 414: ...18 6 MCF5272 User s Manual PWM Programming Model ...
Page 452: ...19 38 MCF5272 User s Manual Power Supply Pins ...
Page 482: ...20 30 MCF5272 User s Manual Reset Operation ...
Page 492: ...21 10 MCF5272 User s Manual Non IEEE 1149 1 Operation ...