C8051F988-GM Silicon Laboratories Inc, C8051F988-GM Datasheet - Page 203

• 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

20.2.4. Programmable Load Capacitance
The programmable load capacitance has 16 values to support crystal oscillators with a wide range of rec-
ommended load capacitance. If Automatic Load Capacitance Stepping is enabled, the crystal load capaci-
tors start at the smallest setting to allow a fast startup time, then slowly increase the capacitance until the
final programmed value is reached. The final programmed loading capacitor value is specified using the
LOADCAP bits in the RTC0XCF register. The LOADCAP setting specifies the amount of on-chip load
capacitance and does not include any stray PCB capacitance. Once the final programmed loading capaci-
tor value is reached, the LOADRDY flag will be set by hardware to logic 1.
When using the SmaRTClock oscillator in Self-Oscillate mode, the programmable load capacitance can be
used to fine tune the oscillation frequency. In most cases, increasing the load capacitor value will result in
a decrease in oscillation frequency.Table 20.2 shows the crystal load capacitance for various settings of
LOADCAP.
LOADCAP
0000
0001
0010
0100
0101
1000
1001
1010
0011
0110
0111
1011
1100
1101
1110
1111
Table 20.2. SmaRTClock Load Capacitance Settings
Crystal Load Capacitance
10.5 pF
12.5 pF
13.5 pF
11.5 pF
4.0 pF
4.5 pF
5.0 pF
5.5 pF
6.0 pF
6.5 pF
7.0 pF
7.5 pF
8.0 pF
8.5 pF
9.0 pF
9.5 pF
Rev. 1.0
C8051F99x-C8051F98x
Equivalent Capacitance seen on
XTAL3 and XTAL4
10.0 pF
12.0 pF
13.0 pF
14.0 pF
15.0 pF
16.0 pF
17.0 pF
18.0 pF
19.0 pF
23.0 pF
25.0 pF
27.0 pF
11.0 pF
21.0 pF
9.0 pF
8.0 pF
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