C8051F321-GM Silicon Laboratories Inc, C8051F321-GM Datasheet - Page 118

• 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
On C8051F320/1 devices, OSCICL is factory calibrated to obtain a 12 MHz base frequency (f
details oscillator programming for C8051F320/1 devices. Electrical specifications for the precision internal oscillator
are given in Table 13.3 on page 126. Note that the system clock may be derived from the programmed internal oscil-
lator divided by 1, 2, 4, or 8, as defined by the IFCN bits in register OSCICN. The divide value defaults to 8 follow-
ing a reset.
13.1.1. Programming the Internal Oscillator on C8051F320/1 Devices
The OSCICL reset value is factory calibrated to result in a 12 MHz internal oscillator with a ±1.5% accuracy; this fre-
quency is suitable for use as the USB clock (see
oscillator as described below.
Important Note: Once the internal oscillator frequency has been modified, the internal oscillator may not be used as
the USB clock as described in
brated frequency following any device reset, at which point the oscillator is suitable for use as the USB clock.
Software should read and adjust the value of OSCICL according to Equation 13.1 to obtain the desired frequency.
The example below shows how to obtain an 11.6 MHz internal oscillator frequency.
Important Note: If the sum of the reset value of OSCICL and ∆OSCICL is greater than 31 or less than 0, then the
device will not be capable of producing the desired frequency.
13.1.2. Internal Oscillator Suspend Mode
The internal oscillator may be placed in Suspend mode by writing ‘1’ to the SUSPEND bit in register OSCICN. In
Suspend mode, the internal oscillator is stopped until a non-idle USB event is detected
matches the polarity selected by the VBPOL bit in register REG0CN
must be enabled for a USB event to be detected.
118
f
f
The required change in period (∆T
Using Equation 13.1 and the above calculations, find ∆OSCICL:
BASE
DES
is the desired internal oscillator frequency; T
is the internal oscillator reset frequency; T
Section
DES
) is the difference between the base period and the desired period.
13.4. The internal oscillator frequency will reset to its original factory-cali-
BASE
Section
DES
Rev. 1.1
is the reset oscillator period.
is the desired oscillator period.
13.4). Software may modify the frequency of the internal
(Section
8.2). Note that the USB transceiver
(Section
BASE
).
Section 13.1.1
15) or VBUS