PXD20RM Datasheet, PDF (268/1628 Pages) Freescale Semiconductor, Inc – PXD20 Microcontroller

Table 9-6. Slave General Purpose Control Register Descriptions
Name
RO
HLP
Bits 2–7
HPEx
Bits
16–21
ARB
Bits
24–25
PCTL
Bit 28
Description
Setting
Read Only - This bit is used to force all of a slave port’s
registers to be read only. Once written to 1 it can only be
cleared by hardware reset.
This bit is initialized by hardware reset.
The reset value is 0
0 All this slave port’s registers can be
written.
1 All this slave port’s registers are read only
and cannot be written (attempted writes have
no effect and result in an error response).
Halt Low Priority - This bit is used to set the initial
arbitration priority of the max_halt_request input.
This bit is initialized by hardware reset.
The reset value is 0
0 The max_halt_request input has the
highest priority for arbitration on this slave
port
1 The max_halt_request input has the
lowest initial priority for arbitration on this
slave port.
Slave General Purpose Control Register Reserved - NA
These bits are reserved for future expansion. They read
as zero and should be written with zero for upward
compatibility.
High Priority Enable - These bits are used to enable the
mX_high_priority inputs for the respective master.
These bits are initialized by hardware reset.
The reset value is 0
0 The mX_high_priority input is disabled on
this slave port
1 The mX_high_priority input is enabled on
this slave port.
Slave General Purpose Control Register Reserved - NA
These bits are reserved for future expansion. They are
read as zero and should be written with zero for upward
compatibility.
Arbitration Mode - These bits are used to select the
arbitration policy for the slave port.
These bits are initialized by hardware reset.
The reset value is 00
00 Fixed Priority.
01 Round Robin (rotating) Priority.
10 Reserved
11 Reserved
Slave General Purpose Control Register Reserved - NA
These bits are reserved for future expansion. They are
read as zero and should be written with zero for upward
compatibility.
Parking Control - These bits determine the parking
control used by this slave port.
These bits are initialized by hardware reset.
The reset value is 00.
00 When no master is making a request the
arbiter will park the slave port on the master
port defined by the PARK bit field.
01 When no master is making a request the
arbiter will park the slave port on the last
master to be in control of the slave port.
10 When no master is making a request the
arbiter will park the slave port on no master
and will drive all outputs to a constant safe
state.
11 Reserved
Slave General Purpose Control Register Reserved - NA
This bit is reserved for future expansion. It is read as zero
and should be written with zero for upward compatibility.
9-10
PXD20 Microcontroller Reference Manual, Rev. 1
Preliminary—Subject to Change Without Notice
Freescale Semiconductor