C8051F314R Silicon Labs, C8051F314R Datasheet - Page 200

• Manufacturer Part Number: C8051F314R
• Description: 8-bit Microcontrollers - MCU 8KB 10ADC
• Manufacturer: Silicon Labs

Specifications of C8051F314R

• Product Category: 8-bit Microcontrollers - MCU
• Core: 8051
• Data Bus Width: 8 bit
• Maximum Clock Frequency: 25 MHz
• Program Memory Size: 8 KB
• Data Ram Size: 1.25 KB
• On-chip Adc: Yes
• Operating Supply Voltage: 2.7 V to 3.6 V
• Package / Case: LQFP-32
• Mounting Style: SMD/SMT
• A/d Bit Size: 10 bit
• A/d Channels Available: 17
• Data Rom Size: 128 B
• Interface Type: I2C, SMBus, SPI, UART
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Number Of Programmable I/os: 29
• Number Of Timers: 5
• On-chip Dac: No
• Processor Series: C8051
• Program Memory Type: Flash
• Factory Pack Quantity: 500
• Supply Voltage - Max: 3.6 V
• Supply Voltage - Min: 2.7 V

C8051F310/1/2/3/4/5/6/7
17.3.2. 8-bit Timers with Auto-Reload
When T3SPLIT is set, Timer 3 operates as two 8-bit timers (TMR3H and TMR3L). Both 8-bit timers oper-
ate in auto-reload mode as shown in Figure 17.5. TMR3RLL holds the reload value for TMR3L; TMR3RLH
holds the reload value for TMR3H. The TR3 bit in TMR3CN handles the run control TMR3H. TMR3L 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 3 Clock Select bits (T3MH and T3ML in CKCON) select either SYSCLK or
the clock defined by the Timer 3 External Clock Select bit (T3XCLK in TMR3CN), as follows:
Note: External clock divided by 8 is synchronized with the system clock, and the external clock must be
less than or equal to the system clock to operate in this mode.
The TF3H bit is set when TMR3H overflows from 0xFF to 0x00; the TF3L bit is set when TMR3L overflows
from 0xFF to 0x00. When Timer 3 interrupts are enabled, an interrupt is generated each time TMR3H over-
flows. If Timer 3 interrupts are enabled and TF3LEN (TMR3CN.5) is set, an interrupt is generated each
time either TMR3L or TMR3H overflows. When TF3LEN is enabled, software must check the TF3H and
TF3L flags to determine the source of the Timer 3 interrupt. The TF3H and TF3L interrupt flags are not
cleared by hardware and must be manually cleared by software.
200
External Clock / 8
T3MH
SYSCLK / 12
0
0
1
T3XCLK
T3XCLK
X
0
1
0
1
Figure 17.7. Timer 3 8-Bit Mode Block Diagram
SYSCLK
External Clock/8
TMR3H Clock
SYSCLK/12
SYSCLK
Source
0
1
1
0
M
T
3
H
M
T
3
L
CKCON
M
T
2
H
M
T
2
L
M
T
1
M
T
0
TR3
S
C
A
1
S
C
A
0
Rev. 1.7
TCLK
TCLK
TMR3RLH
TMR3RLL
TMR3H
TMR3L
T3ML
0
0
1
Reload
Reload
T3XCLK
X
0
1
To ADC
T3SPLIT
TF3LEN
T3XCLK
TF3H
TF3L
TR3
External Clock/8
TMR3L Clock
SYSCLK/12
SYSCLK
Source
Interrupt