c8051f410 Silicon Laboratories, c8051f410 Datasheet - Page 255

• Manufacturer Part Number: c8051f410
• Description: 2.0 V, 32/16 Kb Flash, Smartclock, 12-bit Adc
• Manufacturer: Silicon Laboratories

25.2.4. Frequency Output Mode
Frequency Output Mode produces a programmable-frequency square wave on the module’s associated
CEXn pin. The capture/compare module high byte holds the number of PCA clocks to count before the out-
put is toggled. The frequency of the square wave is then defined by Equation 25.1.
Where F
The lower byte of the capture/compare module is compared to the PCA counter low byte; on a match,
CEXn is toggled and the offset held in the high byte is added to the matched value in PCA0CPLn. Fre-
quency Output Mode is enabled by setting the ECOMn, TOGn, and PWMn bits in the PCA0CPMn register.
Note: A value of 0x00 in the PCA0CPHn register is equal to 256 for this equation.
W
M
P
1
6
n
0
PCA0CPMn
O
M
E
C
n
C
A
P
P
n
0 0 0
C
N
A
P
n
PCA
M
A
T
n
O
G
T
n
1
W
M
P
n
is the frequency of the clock selected by the CPS2-0 bits in the PCA mode register, PCA0MD.
E
C
C
F
n
0
PCA Timebase
Equation 25.1. Square Wave Frequency Output
Enable
Figure 25.7. PCA Frequency Output Mode
Comparator
PCA0CPLn
PCA0L
8-bit
F
CEXn
=
Rev. 1.0
---------------------------------------- -
2
match
×
Enable
Adder
PCA0CPHn
8-bit Adder
F
Toggle
PCA
TOGn
0
1
C8051F410/1/2/3
CEXn
PCA0CPHn
Crossbar
Port I/O
255