C8051F331 Silicon Laboratories Inc, C8051F331 Datasheet - Page 193

• Manufacturer Part Number: C8051F331
• Description: IC 8051 MCU 8K FLASH 20MLP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F33xr

Specifications of C8051F331

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: SMBus (2-Wire/I²C), SPI, UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 17
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-QFN
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Data Converters: -

19.2.4. Frequency Output Mode
Frequency Output Mode produces a programmable-frequency square wave on the module’s associated
CEXn pin. The capture/compare module high byte holds the number of PCA clocks to count before the out-
put is toggled. The frequency of the square wave is then defined by Equation 19.3.
Where F
The lower byte of the capture/compare module is compared to the PCA counter low byte; on a match,
CEXn is toggled and the offset held in the high byte is added to the matched value in PCA0CPLn. Fre-
quency Output Mode is enabled by setting the ECOMn, TOGn, and PWMn bits in the PCA0CPMn register.
Note: A value of 0x00 in the PCA0CPHn register is equal to 256 for this equation.
PCA0CPLn
Write to
Reset
PCA
PCA0CPHn
Write to
is the frequency of the clock selected by the CPS2-0 bits in the PCA mode register, PCA0MD.
0
ENB
ENB
1
W
M
P
1
6
n
x
C
O
M
E
n
Equation 19.3. Square Wave Frequency Output
PCA0CPMn
C
A
P
P
n
0 0 0
C
A
P
N
n
Figure 19.7. PCA Frequency Output Mode
M
A
T
n
O
G
T
n
W
M
P
n
E
C
C
F
n
x
PCA Timebase
F
CEXn
Enable
=
Comparator
PCA0CPLn
C8051F330/1, C8051F330D
---------------------------------------- -
2
Rev. 1.2
PCA0L
8-bit
×
PCA0CPHn
F
PCA
match
Enable
Adder
8-bit Adder
Toggle
TOGn
0
1
CEXn
PCA0CPHn
Crossbar
Port I/O
193