C8051F321-GM Silicon Laboratories Inc, C8051F321-GM Datasheet - Page 224

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

Specifications of C8051F321-GM

• Program Memory Type: FLASH
• Program Memory Size: 16KB (16K x 8)
• Package / Case: 28-VQFN Exposed Pad, 28-HVQFN, 28-SQFN, 28-DHVQFN
• 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
• 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
• 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
• Operating Supply Voltage: 2.7 V to 3.6 V
• 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: 13-ch x 10-bit or 17-ch x 10-bit
• No. Of I/o's: 21
• Ram Memory Size: 1280Byte
• Cpu Speed: 25MHz
• No. Of Timers: 4
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: 336-1480 - DAUGHTER CARD TOOLSTCK C8051F321770-1006 - ISP 4PORT FOR SILABS C8051F MCU336-1449 - ADAPTER PROGRAM TOOLSTICK F321336-1260 - DEV KIT FOR C8051F320/F321
• Eeprom Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1261

C8051F320/1
19.3.3. USB Start-of-Frame Capture
When T3SOF = ‘1’, Timer 3 operates in USB Start-of-Frame (SOF) capture mode. When T3SPLIT = ‘0’,
Timer 3 counts up and overflows from 0xFFFF to 0x0000. Each time a USB SOF is received, the contents
of the Timer 3 registers (TMR3H:TMR3L) are latched into the Timer 3 Reload registers
(TMR3RLH:TMR3RLL). A Timer 3 interrupt is generated if enabled. This mode can be used to calibrate the
system clock or external oscillator against the known USB host SOF clock.
When T3SPLIT = ‘1’, the Timer 3 registers (TMR3H and TMR3L) act as two 8-bit counters. Each counter
counts up independently and overflows from 0xFF to 0x00. Each time a USB SOF is received, the contents
of the Timer 3 registers are latched into the Timer 3 Reload registers (TMR3RLH and TMR3RLL). A
Timer 3 interrupt is generated if enabled.
224
External Clock / 8
SYSCLK / 12
External Clock / 8
T
F
3
H
T
F
3
L
TMR3CN
Figure 19.10. Timer 3 SOF Capture Mode (T3SPLIT = ‘0’)
Figure 19.11. Timer 3 SOF Capture Mode (T3SPLIT = ‘1’)
E
N
T
F
3
L
SYSCLK / 12
O
T
3
S
F
SYSCLK
T
3
S
P
L
T
I
T
R
3
H
T
F
3
T
F
3
L
X
C
K
T
3
L
0
1
TMR3CN
N
T
F
3
L
E
O
T
3
S
F
T
S
P
T
3
L
I
T
R
SYSCLK
3
C
T
3
X
L
K
0
1
Start-of-Frame
M
H
T
3
0
1
1
0
M
T
3
L
0
1
(SOF)
USB
CKCON
M
T
2
H
M
H
T
3
M
T
2
L
M
T
3
L
M
T
1
CKCON
M
T
2
H
M
T
0
M
T
2
L
C
TR3
S
A
1
TR3
M
T
1
S
C
A
0
M
T
0
Rev. 1.4
S
C
A
1
S
C
A
0
Enable
TCLK
TCLK
Capture
TCLK
TMR3RLH
TMR3RLL
TMR3H
TMR3L
TMR3RLL TMR3RLH
TMR3L
Interrupt
Capture
Capture
TMR3H
To ADC
Start-of-Frame
(SOF)
Enable
USB
To ADC
Interrupt