C8051F330 Silicon Laboratories Inc, C8051F330 Datasheet - Page 180

• Manufacturer Part Number: C8051F330
• Description: IC 8051 MCU 8K FLASH 20MLP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F33xr

Specifications of C8051F330

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: SMBus (2-Wire/I²C), SPI, UART/USART
• Peripherals: POR, PWM, Temp Sensor, 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
• Data Converters: A/D 16x10b; D/A 1x10b
• 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: -

C8051F330/1, C8051F330D
18.2.2. 8-bit Timers with Auto-Reload
When T2SPLIT is set, Timer 2 operates as two 8-bit timers (TMR2H and TMR2L). Both 8-bit timers oper-
ate in auto-reload mode as shown in Figure 18.12. TMR2RLL holds the reload value for TMR2L;
TMR2RLH holds the reload value for TMR2H. The TR2 bit in TMR2CN handles the run control for TMR2H.
TMR2L is always running when configured for 8-bit Mode.
Each 8-bit timer may be configured to use SYSCLK, SYSCLK divided by 12, or the external oscillator clock
source divided by 8. The Timer 2 Clock Select bits (T2MH and T2ML in CKCON) select either SYSCLK or
the clock defined by the Timer 2 External Clock Select bit (T2XCLK in TMR2CN), as follows:
The TF2H bit is set when TMR2H overflows from 0xFF to 0x00; the TF2L bit is set when TMR2L overflows
from 0xFF to 0x00. When Timer 2 interrupts are enabled (IE.5), an interrupt is generated each time
TMR2H overflows. If Timer 2 interrupts are enabled and TF2LEN (TMR2CN.5) is set, an interrupt is gener-
ated each time either TMR2L or TMR2H overflows. When TF2LEN is enabled, software must check the
TF2H and TF2L flags to determine the source of the Timer 2 interrupt. The TF2H and TF2L interrupt flags
are not cleared by hardware and must be manually cleared by software.
180
External Clock / 8
T2MH
0
0
1
SYSCLK / 12
T2XCLK
T2XCLK
X
0
1
0
1
SYSCLK / 12
External Clock / 8
SYSCLK
TMR2H Clock Source
SYSCLK
Figure 18.12. Timer 2 8-Bit Mode Block Diagram
0
1
1
0
M
T
3
H
M
T
3
L
CKCON
M
H
T
2
M
T
2
L
M
T
1
M
T
0
TR2
S
C
A
1
C
S
A
0
Rev. 1.2
TCLK
TCLK
TMR2RLH
TMR2RLL
TH2
TL2
T2ML
0
0
1
Reload
Reload
T2XCLK
X
0
1
To SMBus
To ADC,
TF2CEN
T2SPLIT
TF2LEN
T2XCLK
SMBus
TF2H
TF2L
TR2
SYSCLK / 12
External Clock / 8
SYSCLK
TMR2L Clock Source
Interrupt