C8051F047-GQR Silicon Laboratories Inc, C8051F047-GQR Datasheet - Page 312

• Manufacturer Part Number: C8051F047-GQR
• Description: IC 8051 MCU 32K FLASH 64TQFP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F04xr

Specifications of C8051F047-GQR

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: CAN, EBI/EMI, SMBus (2-Wire/I²C), SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 32
• Program Memory Size: 32KB (32K x 8)
• Program Memory Type: FLASH
• Ram Size: 4.25K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Data Converters: A/D 13x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TQFP, 64-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

C8051F040/1/2/3/4/5/6/7
24.2.5. 8-Bit Pulse Width Modulator Mode
Each module can be used independently to generate pulse width modulated (PWM) outputs on its associ-
ated 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 high. When the count value in PCA0L overflows, the CEXn output will be
low (see Figure 24.8). 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) with-
out 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 24.2.
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'.
310
W
M
P
1
6
n
0
PCA0CPMn
O
M
E
C
n
C
A
P
P
n
0 0 0 0
C
A
P
N
n
M
A
T
n
O
G
T
n
W
M
P
n
E
C
C
F
n
0
PCA Timebase
Enable
Figure 24.8. PCA 8-Bit PWM Mode Diagram
Equation 24.2. 8-Bit PWM Duty Cycle
Comparator
PCA0CPHn
PCA0CPLn
PCA0L
8-bit
DutyCycle
Overflow
=
match
Rev. 1.5

-------------------------------------------------- -
256 PCA0CPHn
S
R
–
SET
CLR
Q
Q
256
CEXn

Crossbar
Port I/O