mcf5272 Freescale Semiconductor, Inc, mcf5272 Datasheet - Page 316

• Manufacturer Part Number: mcf5272
• Description: Mcf5272 Coldfire Integrated Microprocessor User
• Manufacturer: Freescale Semiconductor, Inc

PLIC Registers
13.5.8 Loopback Control Register (PLCR)
All bits in this register are cleared on hardware or software reset.
The PLCR is an 8-bit register containing the configuration information for all four ports on
the MCF5272.
13-20
Bits
8
7
3
2
0
1
Name
SHB2
SHB1
ENB2
ENB1
DMX
ACT
Reset
Field
Table 13-2. P0CR–P3CR Field Descriptions (Continued)
GCI Activation.
0 Default reset value.
1 Causes Dout to transition to a logic low for the respective port. This bit is only operational when
the port is in GCI mode. Setting the ACT bit in any other mode has no effect. It is the responsibility
of the CPU to clear the ACT bit when normal operation on Dout is required. This bit is intended to
be used to request activation from the upstream DCL/FSC driver. Periodic interrupts commence as
soon as the upstream device generates DCL, provided the appropriate interrupts, such as IE,
B1RIE, and so on, are enabled for the port.
Data multiplex.
0 port 3 Dout and Din are multiplexed onto Dout1 and Din1.
1 enables port 3 Dout and Din to be connected to dedicated output and input pins, DOUT3 and
B2 channel shift direction.
0 B2 channel data is received/transmitted msb first. The msb-first convention is often used for
1 B2 channel data is received/transmitted lsb first. The lsb-first convention is used when the data is
B1 channel shift direction. See SHB2.
Enable B2 data channel.
0 The B2 channel is disabled and all periodic interrupts in both receive and transmit directions are
1 Enables the B2 data channel for the respective port.
Enable B1 data channel. See ENB2.
Addr
R/W
DIN3.
communication with PCM CODECs and converters.
to be HDLC encoded.
disabled. The behavior of Din and Dout in this state is shown below.
Figure 13-20. Loopback Control Register (PLCR)
7
Mode
GCI
IDL
LM3
6
All 1s
Operational (data on
Din visible)
MCF5272 User’s Manual
5
Din
LM2
MBAR + 0x38F
0000_0000
Read/Write
4
Description
High Impedance
Open drain
3
LM1
Dout
2
1
LM0
0
MOTOROLA