C8051F540-TB Silicon Laboratories Inc, C8051F540-TB Datasheet - Page 256

• Manufacturer Part Number: C8051F540-TB
• Description: BOARD PROTOTYPE W/C8051F540
• Manufacturer: Silicon Laboratories Inc
• Type: MCUr

Specifications of C8051F540-TB

• Contents: Board
• Processor To Be Evaluated: C8051F54x
• Processor Series: C8051F54x
• Interface Type: USB
• Operating Supply Voltage: 5 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: C8051F54x
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1672

C8051F54x
24.3.4. 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 24.1.
Where F
PCA0MD. 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.
Frequency Output Mode is enabled by setting the ECOMn, TOGn, and PWMn bits in the PCA0CPMn reg-
ister. Note that the MATn bit should normally be set to 0 in this mode. If the MATn bit is set to 1, the CCFn
flag for the channel will be set when the 16-bit PCA0 counter and the 16-bit capture/compare register for
the channel are equal.
256
Note: A value of 0x00 in the PCA0CPHn register is equal to 256 for this equation.
PCA0CPLn
Write to
Reset
PCA
PCA0CPHn
Write to
is the frequency of the clock selected by the CPS[2 : 0] bits in the PCA mode register,
0
ENB
ENB
1
PCA
Timebase
Figure 24.6. PCA High-Speed Output Mode Diagram
Enable
Equation 24.1. Square Wave Frequency Output
W
M
P
1
6
n
x
C
O
M
E
n
PCA0CPLn
PCA0CPMn
C
A
P
P
n
0 0
PCA0L
C
N
A
P
n
16-bit Comparator
M
A
T
n
F
O
G
T
n
CEXn
W
M
P
n
0 x
E
C
C
F
n
PCA0CPHn
PCA0H
=
------------------------------------------ -
2 PCA0CPHn
Rev. 1.1

F
PCA
Match
Toggle
C
F
C
R
TOGn
0
1
PCA0CN
C
C
F
5
C
C
F
4
0
1
C
C
F
3
CEXn
C
C
F
2
C
C
F
1
C
C
F
0
PCA Interrupt
Crossbar
Port I/O