
CHAPTER 11 KIU (KEYBOARD INTERFACE UNIT)
User’s Manual U14579EJ2V0UM
179
Figure 11-4. Transition of Sequencer Status
Reset
(software reset)
(KEYEN = 0)Note 1
(KEYEN = 0)
(set KEYEN = 0)
or
(software reset)
(set KEYEN = 1)Note 2
(software reset)
Note 3
(SCANSTP = 1)Note 4
(set SCANSTP = 1)Note 5
or
(set ATSTP = 1 and
stop repeat number full)
(set SCANSTART = 1)Note 6
or
(set ATSCAN = 1 and KPORT touch)
(1 cycle scan end)
(next scan start)
WAIT KEYSCAN STABLE
COUNT
1 cycle scanning
STOP REPEAT NUMBER
COUNT (STPREP)
WAIT INTERVAL
COUNT
KEYEN:
1
SCANSTP:
0
SCANSTART:
0
ATSTP:
1 or 0
ATSCAN:
1
< IntervalNextScan >
KEYEN:
1
SCANSTP:
0
SCANSTART:
0
ATSTP:
1 or 0
ATSCAN:
1
< Scanning >
KEYEN:
1
SCANSTP:
0
SCANSTART:
0
ATSTP:
1 or 0
ATSCAN:
1
< WaitKeyIn >
KEYEN:
0
SCANSTP:
0
SCANSTART:
0
ATSTP:
0
ATSCAN:
1
< Stopped >
Remark
Stopped:
WaitKeyIn:
IntervalNextScan:
KIUSCANS register bit 1 = 0, bit 0 = 0
KIUSCANS register bit 1 = 0, bit 0 = 1
KIUSCANS register bit 1 = 1, bit 0 = 0
Notes 1. When the KEYEN is set to 0 during a scanning operation, the status
changes to the Stopped status after that scanning operation has
completed.
Scanning:
KEYEN:
KIUSCANS register bit 1 = 1, bit 0 = 1
KIUSCANREP register bit 15
2. The KEYEN bit cannot be set to 1 while both bits 1 and 0 of the
SCANLINE register are 1.
STPREP:
SCANSTP:
SCANSTART:
KIUSCANREP register bits 9, 8, 7, 6, 5, 4
KIUSCANREP register bit 3
KIUSCANREP register bit 2
3. When the status changes from the WaitKeyIn mode to the Scanning
mode after the SCANSTP bit is set to 1, the status returns to the
WaitKeyIn mode again after scanning a set of data.
ATSTP:
ATSCAN:
software reset:
KIUSCANREP register bit 1
KIUSCANREP register bit 0
KIURST register bit 0 = 1 write
4. When the SCANSTP bit is set to 1 in the IntervalNextScan mode, the
status changes to the WaitKeyIn mode and the SCANSTP bit becomes
0 simultaneously.
KPORT touch:
stop repeat
number full:
When any of KPORT(7:0) signals is 1
When the scan data is 0 for the number of
times specified by the STPREP register
5. If the SCANSTP bit is set to 1 during a scanning operation, that one set
of data scanning is continued. After this scanning is completed, the
status changes to the WaitKeyIn mode and the SCANSTP bit becomes
0 automatically.
6. The SCANSTART bit becomes automatically 0 when the status changes
to the Scanning mode, except if the SCANSTART bit was set to 1 during
the IntervalNextScan or Scanning mode.