C8051F020DK Silicon Laboratories Inc, C8051F020DK Datasheet - Page 257

DEV KIT FOR F020/F021/F022/F023

C8051F020DK

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

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

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
C8051F020DK
Manufacturer:
SiliconL
Quantity:
10
23.2.5. 8-Bit Pulse Width Modulator Mode
Each module can be used independently to generate pulse width modulated (PWM) outputs on its associated CEXn
pin. The frequency of the output is dependent on the timebase for the PCA0 counter/timer. The duty cycle of the
PWM output signal is varied using the module's PCA0CPLn capture/compare register. When the value in the low
byte of the PCA0 counter/timer (PCA0L) is equal to the value in PCA0CPLn, the output on the CEXn pin will be
asserted high. When the count value in PCA0L overflows, the CEXn output will be asserted low (see Figure 23.8).
Also, when the counter/timer low byte (PCA0L) overflows from 0xFF to 0x00, PCA0CPLn is reloaded automatically
with the value stored in the counter/timer's high byte (PCA0H) without software intervention. Setting the ECOMn
and PWMn bits in the PCA0CPMn register enables 8-Bit Pulse Width Modulator mode. The duty cycle for 8-Bit
PWM Mode is given by Equation 23.2.
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 23.2, the largest duty cycle is 100% (PCA0CPHn = 0), and the smallest duty cycle is 0.39%
(PCA0CPHn = 0xFF). A 0% duty cycle may be generated by clearing the ECOMn bit to ‘0’.
PCA0CPLn
Write to
Reset
PCA0CPHn
Write to
0
1
ENB
ENB
W
M
P
0
1
6
n
Figure 23.8. PCA 8-Bit PWM Mode Diagram
E
C
O
M
n
PCA0CPMn
C
A
P
P
n
0 0 x 0
C
A
P
N
n
Equation 23.2. 8-Bit PWM Duty Cycle
M
A
T
n
O
G
DutyCycle
T
n
W
P
M
n
E
C
C
F
n
x
PCA Timebase
Enable
=
PCA0CPHn
Comparator
PCA0CPLn
-------------------------------------------------- -
PCA0L
256 PCA0CPHn
8-bit
Rev. 1.4
Overflow
256
match
S
R
SET
CLR
Q
Q
C8051F020/1/2/3
CEXn
Crossbar
Port I/O
257

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