C8051F321-GMR Silicon Laboratories Inc, C8051F321-GMR Datasheet - Page 236

• Manufacturer Part Number: C8051F321-GMR
• Description: IC 8051 MCU 16K FLASH 28MLP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F32xr

Specifications of C8051F321-GMR

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: SMBus (2-Wire/I²C), SPI, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 21
• Program Memory Size: 16KB (16K x 8)
• Program Memory Type: FLASH
• Ram Size: 2.25K 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: 28-VQFN Exposed Pad, 28-HVQFN, 28-SQFN, 28-DHVQFN
• Processor Series: C8051F3x
• Core: 8051
• Data Bus Width: 8 bit
• Data Ram Size: 2.25 KB
• Interface Type: I2C, SMBus, SPI, UART, USB
• Maximum Clock Frequency: 25 MHz
• Number Of Programmable I/os: 21
• Number Of Timers: 4
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: PK51, CA51, A51, ULINK2
• Development Tools By Supplier: C8051F320DK
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 13 Channel / 10 bit, 7 Channel
• Package: 28MLP
• Device Core: 8051
• Family Name: C8051F321
• Maximum Speed: 25 MHz
• Operating Supply Voltage: 3.3 V
• For Use With: 336-1480 - DAUGHTER CARD TOOLSTCK C8051F321336-1449 - ADAPTER PROGRAM TOOLSTICK F321336-1260 - DEV KIT FOR C8051F320/F321
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

C8051F320/1
20.2.6. 16-Bit Pulse Width Modulator Mode
A PCA module may also be operated in 16-Bit PWM mode. In this mode, the 16-bit capture/compare mod-
ule defines the number of PCA clocks for the low time of the PWM signal. When the PCA counter matches
the module contents, the output on CEXn is asserted high; when the counter overflows, CEXn is asserted
low. To output a varying duty cycle, new value writes should be synchronized with PCA CCFn match inter-
rupts. 16-Bit PWM Mode is enabled by setting the ECOMn, PWMn, and PWM16n bits in the PCA0CPMn
register. For a varying duty cycle, match interrupts should be enabled (ECCFn = 1 AND MATn = 1) to help
synchronize the capture/compare register writes. The duty cycle for 16-Bit PWM Mode is given by
Equation 20.3.
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 20.3, 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’.
20.3. Watchdog Timer Mode
A programmable watchdog timer (WDT) function is available through the PCA Module 4. The WDT is used
to generate a reset if the time between writes to the WDT update register (PCA0CPH4) exceed a specified
limit. The WDT can be configured and enabled/disabled as needed by software.
With the WDTE and/or WDLCK bits set to ‘1’ in the PCA0MD register, Module 4 operates as a watchdog
timer (WDT). The Module 4 high byte is compared to the PCA counter high byte; the Module 4 low byte
holds the offset to be used when WDT updates are performed. The Watchdog Timer is enabled on
reset. Writes to some PCA registers are restricted while the Watchdog Timer is enabled.
236
PCA0CPLn
Write to
Reset
PCA0CPHn
Write to
0
ENB
ENB
1
W
P
M
1
6
n
1
E
C
O
M
n
PCA0CPMn
C
A
P
P
n
0 0 x 0
C
A
P
N
n
M
A
T
n
PCA Timebase
O
G
T
n
Equation 20.3. 16-Bit PWM Duty Cycle
W
P
M
n
E
C
C
F
n
x
Figure 20.9. PCA 16-Bit PWM Mode
DutyCycle
Enable
PCA0CPHn
PCA0H
=
16-bit Comparator
Rev. 1.4

---------------------------------------------------- -
65536 PCA0CPn
PCA0CPLn
PCA0L
–
65536
Overflow
match
S
R

SET
CLR
Q
Q
CEXn
Crossbar
Port I/O