
DocID13284 Rev 2
341/564
UM0404
The capture / compare units
match was detected, the compare register is reloaded with a new value, this value will not
become effective until the next timer period.
In order to use the respective port pin as compare signal output pin CCxIO for compare
register CCx in compare mode 3 this port pin must be configured as output and the
corresponding direction control bit must be set to ‘1’. With this configuration, the initial state
of the output signal can be programmed or its state can be modified at any time by writing to
the port output latch.
In compare mode 3 the port latch is set upon a compare event and cleared upon a timer
overflow (see
However, when compare value and reload value for a channel are equal the respective
interrupt requests will be generated, only the output signal is not changed (set and clear
would coincide in this case).
Note:
If the port output latch is written to by software at the same time it would be altered by a
compare event, the software write will have priority. In this case the hardware-triggered
change will not become effective.
On channels 24...27 compare mode 1 will generate interrupt requests but no output function
is provided.
16.5.5
Double register compare mode
In double-register compare mode two compare registers work together to control one output
pin. This mode is selected by a special combination of modes for these two registers.
For double-register mode the 16 capture / compare registers of each CAPCOM unit are
regarded as two banks of 8 registers each. Registers CC0...CC7 and CC16...CC23 form
bank 1 while registers CC8...CC15 and CC24...CC31 form bank 2 (respectively). For
double-register mode a bank 1 register and a bank 2 register form a register pair. Both
registers of this register pair operate on the pin associated with the bank 1 register (pins
CC0IO...CC7IO and CC16IO...CC23IO).
The relationship between the bank 1 and bank 2 register of a pair and the effected output
pins for double-register compare mode is listed in the
.
Table 50. Register pairs for double-register compare mode
CAPCOM1 unit
CAPCOM2 unit
Register pair
Associated
output pin
Register pair
Associated
output pin
Bank 1
Bank 2
Bank 1
Bank 2
CC0
CC8
CC0IO
CC16
CC24
CC16IO
CC1
CC9
CC1IO
CC17
CC25
CC17IO
CC2
CC10
CC2IO
CC18
CC26
CC18IO
CC3
CC11
CC3IO
CC19
CC27
CC19IO
CC4
CC12
CC4IO
CC20
CC28
CC20IO
CC5
CC13
CC5IO
CC21
CC29
CC21IO
CC6
CC14
CC6IO
CC22
CC30
CC22IO
CC7
CC15
CC7IO
CC23
CC31
CC23IO