187
8331B–AVR–03/12
Atmel AVR XMEGA AU
• Bit 3:2 – CMD[1:0]: Command
These bits can be used for software control of update, restart, and reset of the timer/counter.
The command bits are always read as zero.
• Bit 1 – LUPD: Lock Update
When this bit is set, no update of the buffered registers is performed, even though an UPDATE
condition has occurred. Locking the update ensures that all buffers, including DTI buffers, are
valid before an update is performed.
This bit has no effect when input capture operation is enabled.
• Bit 0 – DIR: Counter Direction
When zero, this bit indicates that the counter is counting up (incrementing). A one indicates that
the counter is in the down-counting (decrementing) state.
Normally this bit is controlled in hardware by the waveform generation mode or by event actions,
but this bit can also be changed from software.
14.12.9
CTRLGCLR/CTRLGSET – Control register G Clear/Set
Refer to
”CTRLFCLR/CTRLFSET – Control register F Clear/Set” on page 186
for information on
how to access this type of status register.
• Bit 7:5 – Reserved
These bits are unused and reserved for future use. For compatibility with future devices, always
write these bits to zero when this register is written.
• Bit 4:1 – CCxBV: Compare or Capture x Buffer Valid
These bits are set when a new value is written to the corresponding CCxBUF register. These
bits are automatically cleared on an UPDATE condition.
Note that when input capture operation is used, this bit is set on a capture event and cleared if
the corresponding CCxIF is cleared.
• Bit 0 – PERBV: Period Buffer Valid
This bit is set when a new value is written to the PERBUF register. This bit is automatically
cleared on an UPDATE condition.
Table 14-8.
Command selections
CMD
Group Configuration
Command Action
00
NONE
None
01
UPDATE
Force update
10
RESTART
Force restart
11
RESET
Force hard reset (ignored if T/C is not in OFFstate)
Bit
7
6
5
4
3
2
1
0
–
–
–
CCDBV
CCCBV
CCBBV
CCABV
PERBV
CTRLGCLR/SET
Read/Write
R
R
R
R/W
R/W
R/W
R/W
R/W
Initial Value
0
0
0
0
0
0
0
0
