C8051F331-GM Silicon Laboratories Inc, C8051F331-GM Datasheet - Page 181

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

Specifications of C8051F331-GM

• Program Memory Type: FLASH
• Program Memory Size: 8KB (8K x 8)
• Package / Case: 20-QFN
• 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
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: C8051F3x
• Core: 8051
• Data Bus Width: 8 bit
• Data Ram Size: 768 B
• Interface Type: I2C/SMBus/SPI/UART
• Maximum Clock Frequency: 25 MHz
• Number Of Programmable I/os: 17
• Number Of Timers: 4
• Operating Supply Voltage: 2.7 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: KSK-SL-TOOLSTICK, PK51, CA51, A51, ULINK2
• Development Tools By Supplier: C8051F330DK
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 16 Channel
• No. Of I/o's: 17
• Ram Memory Size: 768Byte
• Cpu Speed: 25MHz
• No. Of Timers: 4
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: 770-1006 - ISP 4PORT FOR SILABS C8051F MCU336-1451 - ADAPTER PROGRAM TOOLSTICK F330336-1264 - DEV KIT FOR C8051F330/F331
• Eeprom Size: -
• Data Converters: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1265

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 18.4,
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
Figure 18.4. Timer 2 16-Bit Mode Block Diagram
M
H
T
3
T
M
3
L
CKCON
T
M
H
2
M
T
0
1
2
L
M
T
1
M
T
0
C
S
A
1
C
S
A
0
TR2
TCLK
Rev. 1.7
Overflow
TL2
TMR2RLL TMR2RLH
TMR2L
To SMBus
TMR2H
C8051F330/1/2/3/4/5
Reload
To ADC,
SMBus
T2SPLIT
TF2CEN
T2XCLK
TF2LEN
TF2H
TF2L
TR2
Interrupt
185