C8051F331 Silicon Laboratories Inc, C8051F331 Datasheet - Page 179
C8051F331
Manufacturer Part Number
C8051F331
Description
IC 8051 MCU 8K FLASH 20MLP
Manufacturer
Silicon Laboratories Inc
Series
C8051F33xr
Datasheet
1.C8051F330R.pdf
(208 pages)
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
-
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
C8051F331
Manufacturer:
SILICON LABS/芯科
Quantity:
20 000
Company:
Part Number:
C8051F331-GM
Manufacturer:
SiliconL
Quantity:
1 630
Part Number:
C8051F331-GM
Manufacturer:
SILICON LABS/芯科
Quantity:
20 000
Part Number:
C8051F331-GMR
Manufacturer:
SILICON LABS/芯科
Quantity:
20 000
18.2. Timer 2
Timer 2 is a 16-bit timer formed by two 8-bit SFRs: TMR2L (low byte) and TMR2H (high byte). Timer 2 may
operate in 16-bit auto-reload mode or (split) 8-bit auto-reload mode. The T2SPLIT bit (TMR2CN.3) defines
the Timer 2 operation mode.
Timer 2 may be clocked by the system clock, the system clock divided by 12, or the external oscillator
source divided by 8. The external clock mode is ideal for real-time clock (RTC) functionality, where the
internal oscillator drives the system clock while Timer 2 (and/or the PCA) is clocked by an external preci-
sion oscillator. Note that the external oscillator source divided by 8 is synchronized with the system clock.
18.2.1. 16-bit Timer with Auto-Reload
When T2SPLIT (TMR2CN.3) is zero, Timer 2 operates as a 16-bit timer with auto-reload. Timer 2 can be
clocked by SYSCLK, SYSCLK divided by 12, or the external oscillator clock source divided by 8. As the
16-bit timer register increments and overflows from 0xFFFF to 0x0000, the 16-bit value in the Timer 2
reload registers (TMR2RLH and TMR2RLL) is loaded into the Timer 2 register as shown in Figure 18.11,
and the Timer 2 High Byte Overflow Flag (TMR2CN.7) is set. If Timer 2 interrupts are enabled (if IE.5 is
set), an interrupt will be generated on each Timer 2 overflow. Additionally, if Timer 2 interrupts are enabled
and the TF2LEN bit is set (TMR2CN.5), an interrupt will be generated each time the lower 8 bits (TMR2L)
overflow from 0xFF to 0x00.
External Clock / 8
SYSCLK / 12
SYSCLK
T2XCLK
0
1
M
T
H
3
M
T
3
L
Figure 18.11. Timer 2 16-Bit Mode Block Diagram
CKCON
M
H
T
2
M
T
0
1
2
L
M
T
1
M
T
0
S
C
A
1
C
S
A
0
TR2
TCLK
C8051F330/1, C8051F330D
Rev. 1.2
Overflow
TL2
TMR2RLL TMR2RLH
TL2
To SMBus
TH2
Reload
To ADC,
SMBus
T2SPLIT
TF2LEN
TF2CEN
T2XCLK
TF2H
TF2L
TR2
Interrupt
179