C8051F312 Silicon Laboratories Inc, C8051F312 Datasheet - Page 55

• Manufacturer Part Number: C8051F312
• Description: IC 8051 MCU 8K FLASH 32LQFP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F31xr

Specifications of C8051F312

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: SMBus (2-Wire/I²C), SPI, UART/USART
• Peripherals: POR, PWM, Temp Sensor, WDT
• Number Of I /o: 29
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 1.25K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Data Converters: A/D 21x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-LQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Other names: 336-1151

5.3.2. Tracking Modes
According to Table 5.1, each ADC0 conversion must be preceded by a minimum tracking time for the con-
verted result to be accurate. The AD0TM bit in register ADC0CN controls the ADC0 track-and-hold mode.
In its default state, the ADC0 input is continuously tracked, except when a conversion is in progress. When
the AD0TM bit is logic 1, ADC0 operates in low-power track-and-hold mode. In this mode, each conversion
is preceded by a tracking period of 3 SAR clocks (after the start-of-conversion signal). When the CNVSTR
signal is used to initiate conversions in low-power tracking mode, ADC0 tracks only when CNVSTR is low;
conversion begins on the rising edge of CNVSTR (see Figure 5.4). Tracking can also be disabled (shut-
down) when the device is in low power standby or sleep modes. Low-power track-and-hold mode is also
useful when AMUX settings are frequently changed, due to the settling time requirements described in
Section “5.3.3. Settling Time Requirements” on page
(AD0CM[2:0]=000, 001,010
Timer 1, Timer 3 Overflow
Write '1' to AD0BUSY,
(AD0CM[2:0]=100)
Timer 0, Timer 2,
Figure 5.4. 10-Bit ADC Track and Conversion Example Timing
SAR Clocks
SAR Clocks
SAR Clocks
AD0TM=1
AD0TM=0
011, 101)
AD0TM=1
AD0TM=0
CNVSTR
Low Power
or Convert
Low Power
or Convert
Track or
Convert
A. ADC0 Timing for External Trigger Source
Track or Convert
B. ADC0 Timing for Internal Trigger Source
1
1
Track
2
2
Track
Rev. 1.7
3
3
4
4
1
C8051F310/1/2/3/4/5/6/7
Convert
5
5
56.
2
6
6
3
7
7
4
8
Convert
8
Convert
Convert
5
9
9
6
10 11 12
10 11
7
8
9
13 14
10 11
Low Power Mode
Track
Low Power
Mode
Track
55