C8051F020DK Silicon Laboratories Inc, C8051F020DK Datasheet - Page 258

• Manufacturer Part Number: C8051F020DK
• Description: DEV KIT FOR F020/F021/F022/F023
• Manufacturer: Silicon Laboratories Inc
• Type: MCUr

Specifications of C8051F020DK

• Contents: Evaluation Board, Power Supply, USB Cables, Adapter and Documentation
• Processor To Be Evaluated: C8051F02x
• Interface Type: USB
• Silicon Manufacturer: Silicon Labs
• Core Architecture: 8051
• Silicon Core Number: C8051F020
• Silicon Family Name: C8051F02x
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: Silicon Laboratories C8051 F020/021/022/023
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1200

C8051F020/1/2/3
23.2.6. 16-Bit Pulse Width Modulator Mode
Each PCA0 module may also be operated in 16-Bit PWM mode. In this mode, the 16-bit capture/compare module
defines the number of PCA0 clocks for the low time of the PWM signal. When the PCA0 counter matches the module
contents, the output on CEXn is asserted high; when the counter overflows, CEXn is asserted low. To output a vary-
ing duty cycle, new value writes should be synchronized with PCA0 CCFn match interrupts. 16-Bit PWM Mode is
enabled by setting the ECOMn, PWMn, and PWM16n bits in the PCA0CPMn register. For a varying duty cycle,
CCFn should also be set to logic 1 to enable match interrupts. The duty cycle for 16-Bit PWM Mode is given by
Equation 23.3.
Important Note About Capture/Compare Registers: When writing a 16-bit value to the PCA0 Capture/Compare
registers, the low byte should always be written first. Writing to PCA0CPLn clears the ECOMn bit to ‘0’; writing to
PCA0CPHn sets ECOMn to ‘1’
Using Equation 23.3, the largest duty cycle is 100% (PCA0CPn = 0), and the smallest duty cycle is 0.0015%
(PCA0CPn = 0xFFFF). A 0% duty cycle may be generated by clearing the ECOMn bit to ‘0’.
258
W
M
P
1
6
n
1
PCA0CPMn
C
O
M
E
n
C
A
P
P
n
0 0 0 0
C
A
P
N
n
M
A
T
n
PCA Timebase
O
G
T
n
W
P
M
n
E
C
C
F
n
0
Enable
PCA0CPHn
Equation 23.3. 16-Bit PWM Duty Cycle
PCA0H
Figure 23.9. PCA 16-Bit PWM Mode
DutyCycle
16-bit Comparator
PCA0CPLn
PCA0L
=
Rev. 1.4

---------------------------------------------------- -
65536 PCA0CPn
Overflow
–
65536
match
S
R
SET
CLR
Q
Q

CEXn
Crossbar
Port I/O