C8051F321-GMR Silicon Laboratories Inc, C8051F321-GMR Datasheet - Page 222

• Manufacturer Part Number: C8051F321-GMR
• Description: IC 8051 MCU 16K FLASH 28MLP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F32xr

Specifications of C8051F321-GMR

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: SMBus (2-Wire/I²C), SPI, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 21
• Program Memory Size: 16KB (16K x 8)
• Program Memory Type: FLASH
• Ram Size: 2.25K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Data Converters: A/D 13x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-VQFN Exposed Pad, 28-HVQFN, 28-SQFN, 28-DHVQFN
• Processor Series: C8051F3x
• Core: 8051
• Data Bus Width: 8 bit
• Data Ram Size: 2.25 KB
• Interface Type: I2C, SMBus, SPI, UART, USB
• Maximum Clock Frequency: 25 MHz
• Number Of Programmable I/os: 21
• Number Of Timers: 4
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: PK51, CA51, A51, ULINK2
• Development Tools By Supplier: C8051F320DK
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 13 Channel / 10 bit, 7 Channel
• Package: 28MLP
• Device Core: 8051
• Family Name: C8051F321
• Maximum Speed: 25 MHz
• Operating Supply Voltage: 3.3 V
• For Use With: 336-1480 - DAUGHTER CARD TOOLSTCK C8051F321336-1449 - ADAPTER PROGRAM TOOLSTICK F321336-1260 - DEV KIT FOR C8051F320/F321
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

C8051F320/1
19.3. Timer 3
Timer 3 is a 16-bit timer formed by two 8-bit SFRs: TMR3L (low byte) and TMR3H (high byte). Timer 3 may
operate in 16-bit auto-reload mode, (split) 8-bit auto-reload mode, or USB Start-of-Frame (SOF) capture
mode. The Timer 3 operation mode is defined by the T3SPLIT (TMR3CN.3) and T3SOF (TMR2CN.4) bits.
Timer 3 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 3 (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.
19.3.1. 16-bit Timer with Auto-Reload
When T3SPLIT (TMR3CN.3) is zero, Timer 3 operates as a 16-bit timer with auto-reload. Timer 3 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 3
reload registers (TMR3RLH and TM3RLL) is loaded into the Timer 3 register as shown in Figure 19.4, and
the Timer 3 High Byte Overflow Flag (TMR3CN.7) is set. If Timer 3 interrupts are enabled, an interrupt will
be generated on each Timer 3 overflow. Additionally, if Timer 3 interrupts are enabled and the TF3LEN bit
is set (TMR3CN.5), an interrupt will be generated each time the lower 8 bits (TMR3L) overflow from 0xFF
to 0x00.
222
External Clock / 8
SYSCLK / 12
SYSCLK
T3XCLK
0
1
Figure 19.8. Timer 3 16-Bit Mode Block Diagram
M
H
T
3
M
T
3
L
0
1
CKCON
M
H
T
2
M
T
2
L
T
M
1
M
T
0
S
C
A
1
TR3
C
S
A
0
TCLK
Rev. 1.4
TMR3RLL TMR3RLH
TMR3L
TMR3H
Reload
To ADC
T3SPLIT
TF3LEN
T3XCLK
T3SOF
TF3H
TF3L
TR3
Interrupt