MPC563XM Reference Manual, Rev. 1
666
Freescale Semiconductor
Preliminary—Subject to Change Without Notice
Data written to A2 and B2 are transfered to A1 and B1, respectively, on the next system clock cycle if
OU[n] bit of EMIOSOUDIS register is cleared (see
). The transfer is blocked if OU[n] bit is
set. Comparator A is enabled only after the transfer to A1 register occurs and is disabled on the next A
match. Comparator B is enabled only after the transfer to B1 register occurs and is disabled on the next B
match. Comparators A and B are enabled and disabled independently.
The output flip-flop is set to the value of EDPOL when a match occurs on comparator A and to the
complement of EDPOL when a match occurs on comparator B.
MODE[6] controls if the FLAG is set on both matches (MODE[0:6]=0000111) or just on the B match
(MODE[0:6]=0000110). FLAG bit assertion depends on comparator enabling.
If subsequent enabled output compares occur on registers A1 and B1, pulses will continue to be generated,
regardless of the state of the FLAG bit.
At any time, the FORCMA and FORCMB bits allow the software to force the output flip-flop to the level
corresponding to a comparison event in comparator A or B, respectively. Note that the FLAG bit is not
affected by these forced operations.
NOTE
If both registers (A1 and B1) are loaded with the same value, the B match
prevails concerning the output pin state (output flip-flop is set to the
complement of EDPOL), the FLAG bit is set and both comparators are
disabled.
show how the Unified Channel can be used to generate a single output
pulse with FLAG bit being set on the second match or on both matches, respectively.
Figure 22-34. Double Action Output Compare with FLAG set on the second match
selected counter bus
$000500
$001000
$001100
$001000
$001100
A1 value
1
B1 value
2
$xxxxxx $001100
$001100
$001100
$xxxxxx $001000
$001000
$001000
output flip-flop
MODE
A1 match
B1 match
Update to
A1 and B1
FLAG pin/register
A1 match
B1 match
[6]
= 0
Notes: 1. EMIOSA[n] = A1 (when reading)
2. EMIOSB[n] = B1 (when reading)
A2 = A1according to OU[n] bit
B2 = B1according to OU[n] bit