C8051F131R Silicon Labs, C8051F131R Datasheet - Page 75

• Manufacturer Part Number: C8051F131R
• Description: 8-bit Microcontrollers - MCU 128kB 100MIPS 8448B RAM
• Manufacturer: Silicon Labs

Specifications of C8051F131R

• Product Category: 8-bit Microcontrollers - MCU
• Core: 8051
• Data Bus Width: 8 bit
• Maximum Clock Frequency: 100 MHz
• Program Memory Size: 128 KB
• Data Ram Size: 8.25 KB
• On-chip Adc: Yes
• Operating Supply Voltage: 2.7 V to 3.6 V
• Package / Case: TQFP-64
• Mounting Style: SMD/SMT
• A/d Bit Size: 10 bit
• A/d Channels Available: 9
• Data Rom Size: 64 KB
• Interface Type: I2C, SMBus, SPI, UART
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Number Of Programmable I/os: 32
• Number Of Timers: 16 bit
• Processor Series: C8051
• Program Memory Type: Flash
• Factory Pack Quantity: 500
• Supply Voltage - Max: 3.6 V
• Supply Voltage - Min: 3 V

6.2.
ADC0 has a maximum conversion speed of 100 ksps. The ADC0 conversion clock is derived from the sys-
tem clock divided by the value held in the ADCSC bits of register ADC0CF.
6.2.1. Starting a Conversion
A conversion can be initiated in one of four ways, depending on the programmed states of the ADC0 Start
of Conversion Mode bits (AD0CM1, AD0CM0) in ADC0CN. Conversions may be initiated by:
The AD0BUSY bit is set to logic 1 during conversion and restored to logic 0 when conversion is complete.
The falling edge of AD0BUSY triggers an interrupt (when enabled) and sets the AD0INT interrupt flag
(ADC0CN.5). Converted data is available in the ADC0 data word MSB and LSB registers, ADC0H, ADC0L.
Converted data can be either left or right justified in the ADC0H:ADC0L register pair (see example in
Figure 6.5) depending on the programmed state of the AD0LJST bit in the ADC0CN register.
When initiating conversions by writing a ‘1’ to AD0BUSY, the AD0INT bit should be polled to determine
when a conversion has completed (ADC0 interrupts may also be used). The recommended polling proce-
dure is shown below.
When CNVSTR0 is used as a conversion start source, it must be enabled in the crossbar, and the corre-
sponding pin must be set to open-drain, high-impedance mode (see
page 235
ADC Modes of Operation
1. Writing a ‘1’ to the AD0BUSY bit of ADC0CN;
2. A Timer 3 overflow (i.e. timed continuous conversions);
3. A rising edge detected on the external ADC convert start signal, CNVSTR0;
4. A Timer 2 overflow (i.e. timed continuous conversions).
Step 1. Write a ‘0’ to AD0INT;
Step 2. Write a ‘1’ to AD0BUSY;
Step 3. Poll AD0INT for ‘1’;
Step 4. Process ADC0 data.
for more details on Port I/O configuration).
Rev. 1.4
C8051F120/1/2/3/4/5/6/7
Section “18. Port Input/Output” on
C8051F130/1/2/3
75