C8051F988-GM Silicon Laboratories Inc, C8051F988-GM Datasheet - Page 202

• Manufacturer Part Number: C8051F988-GM
• Description: IC MCU 8BIT 4KB FLASH 24QFN
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F9xxr

Specifications of C8051F988-GM

• Program Memory Type: FLASH
• Program Memory Size: 4KB (4K x 8)
• Package / Case: 24-UQFN Exposed Pad, 24-HUQFN
• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: SMBus (2-Wire/I²C), SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 17
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 3.6 V
• Data Converters: A/D 10x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: C8051F9x
• Core: 8051
• Data Ram Size: 512 B
• Interface Type: I2C, SMBus, Enhanced UART, Enhanced SPI
• Maximum Clock Frequency: 7 KHz
• Number Of Programmable I/os: 17
• Number Of Timers: 4
• Operating Supply Voltage: 2.4 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: PK51, CA51, A51, ULINK2
• Development Tools By Supplier: C8051F996DK
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 10 Channel
• On-chip Dac: 10 bit, 4 Channel
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1959-5

C8051F99x-C8051F98x
20.2.2. Using the SmaRTClock Oscillator in Self-Oscillate Mode
When using Self-Oscillate Mode, the XTAL3 and XTAL4 pins are internally shorted together. The following
steps show how to configure SmaRTClock for use in Self-Oscillate Mode:
1. Set SmaRTClock to Self-Oscillate Mode (XMODE = 0).
2. Set the desired oscillation frequency:
3. The oscillator starts oscillating instantaneously.
4. Fine tune the oscillation frequency by adjusting the load capacitance (RTC0XCF).
20.2.3. Using the Low Frequency Oscillator (LFO)
The low frequency oscillator provides an ultra low power, on-chip clock source to the SmaRTClock. The
typical frequency of oscillation is 16.4 kHz ±20%. No external components are required to use the LFO and
the XTAL3 and XTAL4 pins do not need to be shorted together.
The following steps show how to configure SmaRTClock for use with the LFO:
1. Enable and select the Low Frequency Oscillator (LFOEN = 1).
2. The LFO starts oscillating instantaneously.
When the LFO is enabled, the SmaRTClock oscillator increments bit 1 of the 32-bit timer (instead of bit 0).
This effectively multiplies the LFO frequency by 2, making the RTC timebase behave as if a 32.768 kHz
crystal is connected at the output.
202
For oscillation at about 20 kHz, set BIASX2 = 0.
For oscillation at about 40 kHz, set BIASX2 = 1.
Rev. 1.0