MPC563XM Reference Manual, Rev. 1
802
Freescale Semiconductor
Preliminary—Subject to Change Without Notice
23.4.5.1
Channel Registers and Flags
Channel configuration and control registers can be divided in the following groups:
•
Host Configuration and Control registers
, which define channel Function and parameter
allocation in SPRAM, input signal filtering, manage Host interrupts, and are used for Host Service
Requests; they can only be accessed by Host, except for the Function Mode bits which can be also
tested by microcode.
•
Event Registers
, which can only be accessed by eTPU Microengine, through dedicated Channel
Control microinstruction operations (see
Section 23.4.9.3, “Channel Control and Configuration
”); these registers are directly used to implement channel functionality, and
include channel event status latches which can be directly tested by Microengine branch
instructions.
•
Pin Control registers
, which basically define pin state and transition polarity (but not input signal
filtering); they are accessible only by dedicated Channel Control microinstruction operations.
•
Link registers
, which implement the channel link mechanism that allows one channel to request
service to another one; they are accessible only by microinstruction operations.
•
General Channel registers
: CHAN, SRI, Flag0/1, PDCM, UDCM.
Most of those registers are channel exclusive, i.e., there is one copy of them for each channel. Microcode
can access registers from only one channel at a time. The Channel Selection (CHAN) register (see
“Channel Selection Register - CHAN
”), accessible only by microcode, defines the channel whose registers
are being accessed, with exception of link register and function mode. CHAN register assumes the value
of the channel to be serviced at the beginning of TST.
The Service Request Inhibit - SRI - register controls the generation of Service Requests on matches and
transitions, also affecting channel logic behavior. For a full description see
Match/Transition Service Request Inhibit Latch
. Flag0/1 are used to select channel service threads based
on channel software state. See
Section , “Flag1,Flag0 - Channel “state resolution” flags
for more details.
Host Configuration and Control registers are described in
Section 23.3.7, “Channel Configuration and
.”
Time Base configuration is common to all channels, and described in
.” Time
Base selection for matches and captures, however, is individual to each channel, and is part of the Event
Registers.
Link registers are described in
Section 23.4.5.5, “Channel Link
The following sections describe the Event Registers and Pin Control registers.
23.4.5.1.1
ER - Event Registers
Each channel contains two identical Event Register sets, named ER1 and ER2, corresponding to the two
actions supported. Each Event Register set contains:
•
a 24-bit Match register (Match1 or Match2), which holds a match value. This value is compared
against the selected match time base (TCR1 or TCR2).