C8051F702-GQ Silicon Laboratories Inc, C8051F702-GQ Datasheet - Page 292

• Manufacturer Part Number: C8051F702-GQ
• Description: IC 8051 MCU 16K FLASH 64-TQFP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F70xr

Specifications of C8051F702-GQ

• Program Memory Type: FLASH
• Program Memory Size: 16KB (16K x 8)
• Package / Case: 64-TQFP, 64-VQFP
• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: EBI/EMI, SMBus (2-Wire/I²C), SPI, UART/USART
• Peripherals: Cap Sense, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 54
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 3.6 V
• Data Converters: A/D 16x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: C8051F7x
• Core: 8051
• Data Bus Width: 8 bit
• Data Ram Size: 512 B
• Interface Type: I2C, SPI, UART
• Maximum Clock Frequency: 25 MHz
• Number Of Programmable I/os: 54
• Number Of Timers: 4 x 16 bit
• Operating Supply Voltage: 1.8 V to 3.3 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: PK51, CA51, A51, ULINK2
• Development Tools By Supplier: C8051F700DK
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 16 Channel
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: 336-1635 - DEV KIT FOR C8051F700
• Eeprom Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1608

C8051F70x/71x
34.3.5. 8-bit, 9-bit, 10-bit and 11-bit Pulse Width Modulator Modes
Each module can be used independently to generate a pulse width modulated (PWM) output on its associ-
ated CEXn pin. The frequency of the output is dependent on the timebase for the PCA counter/timer, and
the setting of the PWM cycle length (8, 9, 10 or 11-bits). For backwards-compatibility with the 8-bit PWM
mode available on other devices, the 8-bit PWM mode operates slightly different than 9, 10 and 11-bit
PWM modes. It is important to note that all channels configured for 8/9/10/11-bit PWM mode will use
the same cycle length. It is not possible to configure one channel for 8-bit PWM mode and another for 11-
bit mode (for example). However, other PCA channels can be configured to Pin Capture, High-Speed Out-
put, Software Timer, Frequency Output, or 16-bit PWM mode independently.
34.3.5.1.
The duty cycle of the PWM output signal in 8-bit PWM mode is varied using the module's PCA0CPLn cap-
ture/compare register. When the value in the low byte of the PCA counter/timer (PCA0L) is equal to the
value in PCA0CPLn, the output on the CEXn pin will be set. When the count value in PCA0L overflows, the
CEXn output will be reset (see Figure 34.8). Also, when the counter/timer low byte (PCA0L) overflows from
0xFF to 0x00, PCA0CPLn is reloaded automatically with the value stored in the module’s capture/compare
high byte (PCA0CPHn) without software intervention. Setting the ECOMn and PWMn bits in the
PCA0CPMn register, and setting the CLSEL bits in register PCA0PWM to 00b enables 8-Bit Pulse Width
Modulator mode. If the MATn bit is set to 1, the CCFn flag for the module will be set each time an 8-bit
comparator match (rising edge) occurs. The COVF flag in PCA0PWM can be used to detect the overflow
(falling edge), which will occur every 256 PCA clock cycles. The duty cycle for 8-Bit PWM Mode is given in
Equation 34.2.
Important Note About Capture/Compare Registers: When writing a 16-bit value to the PCA0 Cap-
ture/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 34.2, 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.
292
PCA0CPLn
Write to
Reset
PCA0CPHn
R
A
S
E
L
0
Write to
C
O
PCA0PWM
E
V
x
8-bit Pulse Width Modulator Mode
C
O
V
F
0
ENB
ENB
1
C
L
S
E
L
1
0
C
L
S
E
L
0
0
W
M
P
1
6
n
0
E
C
O
M
n
PCA0CPMn
C
A
P
P
n
0 0 x 0
Figure 34.8. PCA 8-Bit PWM Mode Diagram
C
A
P
N
n
M
A
T
n
Equation 34.2. 8-Bit PWM Duty Cycle
O
G
T
n
Duty Cycle
W
M
P
n
C
C
E
F
n
x
PCA Timebase
Enable
=
PCA0CPHn
Comparator
PCA0CPLn
Rev. 1.0

-------------------------------------------------- -
PCA0L
256 PCA0CPHn
8-bit
–
256
Overflow
COVF
match
S
R
SET
CLR

Q
Q
CEXn
Crossbar
Port I/O