C8051F040DK Silicon Laboratories Inc, C8051F040DK Datasheet - Page 311

• Manufacturer Part Number: C8051F040DK
• Description: DEV KIT FOR F040/F041/F042/F043
• Manufacturer: Silicon Laboratories Inc
• Type: MCUr

Specifications of C8051F040DK

• Contents: Evaluation Board, Power Supply, USB Cables, Adapter and Documentation
• Processor To Be Evaluated: C8051F04x
• Interface Type: USB
• Silicon Manufacturer: Silicon Labs
• Core Architecture: 8051
• Silicon Core Number: C8051F040
• Silicon Family Name: C8051F04x
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: Silicon Laboratories C8051 F040, 041, 042, 043 MCUs
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1205

24.2.4. 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 24.1, where F
quency of the clock selected by the CPS2-0 bits in the PCA mode register, PCA0MD.
Note: A value of 0x00 in the PCA0CPHn register is equal to 256 for this equation.
The lower byte of the capture/compare module is compared to the PCA0 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.
W
P
M
1
6
n
0
PCA0CPMn
E
C
O
M
n
C
A
P
P
n
0 0 0
C
A
P
N
n
M
A
T
n
O
G
T
n
1
W
M
P
n
E
C
C
F
n
0
PCA Timebase
Equation 24.1. Square Wave Frequency Output
Enable
Figure 24.7. PCA Frequency Output Mode
Comparator
PCA0CPLn
PCA0L
8-bit
F
sqr
=
---------------------------------------- -
2 PCA0CPHn
Rev. 1.5

match
Enable
Adder
8-bit Adder
F
C8051F040/1/2/3/4/5/6/7
PCA
Toggle
TOGn
0
1
CEXn
PCA0CPHn
Crossbar
PCA
Port I/O
is the fre-
309