C8051F131R Silicon Labs, C8051F131R Datasheet - Page 332

• Manufacturer Part Number: C8051F131R
• Description: 8-bit Microcontrollers - MCU 128kB 100MIPS 8448B RAM
• Manufacturer: Silicon Labs

Specifications of C8051F131R

• Product Category: 8-bit Microcontrollers - MCU
• Core: 8051
• Data Bus Width: 8 bit
• Maximum Clock Frequency: 100 MHz
• Program Memory Size: 128 KB
• Data Ram Size: 8.25 KB
• On-chip Adc: Yes
• Operating Supply Voltage: 2.7 V to 3.6 V
• Package / Case: TQFP-64
• Mounting Style: SMD/SMT
• A/d Bit Size: 10 bit
• A/d Channels Available: 9
• Data Rom Size: 64 KB
• Interface Type: I2C, SMBus, SPI, UART
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Number Of Programmable I/os: 32
• Number Of Timers: 16 bit
• Processor Series: C8051
• Program Memory Type: Flash
• Factory Pack Quantity: 500
• Supply Voltage - Max: 3.6 V
• Supply Voltage - Min: 3 V

C8051F120/1/2/3/4/5/6/7
C8051F130/1/2/3
24.2.4. 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 24.1.
Note: A value of 0x00 in the PCA0CPHn register is equal to 256 for this equation.
Where F
PCA0MD. The lower byte of the capture/compare module is compared to the PCA0 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.
Frequency Output Mode is enabled by setting the ECOMn, TOGn, and PWMn bits in the PCA0CPMn reg-
ister.
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’.
332
W
M
P
1
6
n
0
PCA0CPMn
E
C
O
M
n
C
A
P
P
n
0 0 0
C
A
P
N
n
M
A
PCA
T
n
O
G
T
n
1
W
M
P
n
is the frequency of the clock selected by the CPS2–0 bits in the PCA mode register,
E
C
C
F
n
0
PCA Timebase
Equation 24.1. Square Wave Frequency Output
Enable
Figure 24.7. PCA Frequency Output Mode
Comparator
PCA0CPLn
PCA0L
8-bit
F
sqr
=
---------------------------------------- -
2 PCA0CPHn
Rev. 1.4

match
Enable
Adder
8-bit Adder
F
PCA
Toggle
TOGn
0
1
CEXn
PCA0CPHn
Crossbar
Port I/O