13-22
MPC561/MPC563 Reference Manual
MOTOROLA
Programming the QADC64E Registers
Table 13-14. QASR0 Bit Descriptions
Bits
Name
Description
0
CF1
Queue 1 Completion Flag. CF1 indicates that a queue 1 scan has been completed. The
scan completion flag is set by the QADC64E when the input channel sample requested by
the last CCW in queue 1 is converted, and the result is stored in the result table.
The end-of-queue 1 is identified when execution is complete on the CCW in the location
prior to that pointed to by BQ2, when the current CCW contains an end-of-queue code
instead of a valid channel number, or when the currently completed CCW is in the last
location of the CCW RAM.
When CF1 is set and interrupts are enabled for that queue completion flag, the QADC64E
asserts an interrupt request at the level specified by IRL1 in the interrupt register
(QADCINT). The software reads the completion flag during an interrupt service routine to
identify the interrupt request. The interrupt request is cleared when the software writes a
zero to the completion flag bit, when the bit was previously read as a one. Once set, only
software or reset can clear CF1.
CF1 is maintained by the QADC64E regardless of whether the corresponding interrupt is
enabled. The software polls for CF1 bit to see if it is set. This allows the software to
recognize that the QADC64E is finished with a queue 1 scan. The software acknowledges
that it has detected the completion flag being set by writing a zero to the completion flag
after the bit was read as a one.
1
PF1
Queue 1 Pause Flag. PF1 indicates that a queue 1 scan has reached a pause. PF1 is set
by the QADC64E when the current queue 1 CCW has the pause bit set, the selected input
channel has been converted, and the result has been stored in the result table.
Once PF1 is set, the queue enters the paused state and waits for a trigger event to allow
queue execution to continue. However, if the CCW with the pause bit set is the last CCW
in a queue, the queue execution is complete. The queue status becomes idle, not paused,
and both the pause and completion flags are set. Another exception occurs in software
controlled mode, where the PF1 can be set but queue 1 never enters the pause state since
queue 1 continues without pausing.
When PF1 is set and interrupts are enabled for the corresponding queue, the QADC64E
asserts an interrupt request at the level specified by IRL1 in the interrupt register. The
software may read PF1 during an interrupt service routine to identify the interrupt request.
The interrupt request is cleared when the software writes a zero to PF1, when the bit was
previously read as a one. Once set, only software or reset can clear PF1.
In external gated single-scan and continuous-scan mode the definition of PF1 has been
redefined. When the gate closes before the end-of-queue 1 is reached, PF1 becomes set
to indicate that an incomplete scan has occurred.In single-scan mode, setting PF1 can be
used to cause an interrupt and software can then determine if queue 1 should be enabled
again. In either external gated mode, setting PF1 indicates that the results for queue 1 have
not been collected during one scan (coherently).
NOTE: If a pause in a CCW is encountered in external gated mode for either single-scan
and continuous-scan mode, the pause flag will not set, and execution continues without
pausing. This has allowed for the added definition of PF1 in the external gated modes.
PF1 is maintained by the QADC64E regardless of whether the corresponding interrupts are
enabled. The software may poll PF1 to find out when the QADC64E has reached a pause
in scanning a queue.The software acknowledges that it has detected a pause flag being set
by writing a zero to PF1 after the bit was last read as a one.
0 = queue 1 has not reached a pause (or gate has not closed before end-of-queue in gated
mode)
1 = queue 1 has reached a pause (or gate closed before end-of-queue in gated mode)
Refer to
Table 13-15 for a summary of pause response in all scan modes.