C8051F321-GM Silicon Laboratories Inc, C8051F321-GM Datasheet - Page 219

• 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

19.2.3. USB Start-of-Frame Capture
When T2SOF = ‘1’, Timer 2 operates in USB Start-of-Frame (SOF) capture mode. When T2SPLIT = ‘0’,
Timer 2 counts up and overflows from 0xFFFF to 0x0000. Each time a USB SOF is received, the contents
of
(TMR2RLH:TMR2RLL). A Timer 2 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 T2SPLIT = ‘1’, the Timer 2 registers (TMR2H and TMR2L) 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 2 registers are latched into the Timer 2 Reload registers (TMR2RLH and TMR2RLL). A
Timer 2 interrupt is generated if enabled.
the
External Clock / 8
Timer 2
SYSCLK / 12
External Clock / 8
T
F
2
H
T
F
2
L
SYSCLK / 12
TMR2CN
Figure 19.6. Timer 2 SOF Capture Mode (T2SPLIT = ‘0’)
Figure 19.7. Timer 2 SOF Capture Mode (T2SPLIT = ‘1’)
T
F
2
L
E
N
O
T
2
S
F
registers
SYSCLK
T
2
S
P
L
T
I
H
R
T
F
2
T
2
T
F
2
L
TMR2CN
C
T
F
2
L
E
N
T
2
X
L
K
0
1
T
S
O
F
2
S
P
T
2
L
T
I
R
T
2
SYSCLK
(TMR2H:TMR2L)
T
2
X
C
L
K
0
1
M
H
T
3
M
T
3
L
Start-of-Frame
CKCON
M
T
2
H
0
1
1
0
T
M
0
1
2
L
M
H
T
3
(SOF)
USB
M
T
1
M
T
3
L
M
CKCON
T
0
M
H
T
2
S
C
A
1
M
T
2
L
S
C
A
0
M
T
1
M
T
0
TR2
TR2
S
C
A
1
S
C
A
0
Rev. 1.4
are
Enable
Capture
TCLK
TCLK
TCLK
latched
Overflow
TMR2RLH
TMR2RLL
TL2
TMR2H
TMR2L
TMR2RLL TMR2RLH
TMR2L
Interrupt
into
Capture
Capture
To SMBus
TMR2H
To SMBus
To ADC,
SMBus
the
Timer 2
C8051F320/1
Start-of-Frame
Enable
(SOF)
USB
To ADC,
SMBus
Reload
Interrupt
registers
219