C8051F320 Silicon Laboratories Inc, C8051F320 Datasheet - Page 55

• Manufacturer Part Number: C8051F320
• Description: IC 8051 MCU 16K FLASH 32LQFP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F32xr

Specifications of C8051F320

• 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: 25
• Program Memory Size: 16KB (16K x 8)
• Program Memory Type: FLASH
• Ram Size: 2.25K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Data Converters: A/D 17x10b
• 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: -

6.
The Voltage reference MUX on C8051F320/1 devices is configurable to use an externally connected voltage refer-
ence, the internal reference voltage generator, or the power supply voltage VDD (see Figure 6.1). The REFSL bit in
the Reference Control register (REF0CN) selects the reference source. For the internal reference or an external
source, REFSL should be set to ‘0’; For VDD as the reference source, REFSL should be set to ‘1’.
The BIASE bit enables the internal ADC bias generator, which is used by the ADC and Internal Oscillator. This
enable is forced to logic 1 when either of the aforementioned peripherals is enabled. The ADC bias generator may be
enabled manually by writing a ‘1’ to the BIASE bit in register REF0CN; see Figure 6.2 for REF0CN register details.
The Reference bias generator (see Figure 6.1) is used by the Internal Voltage Reference, Temperature Sensor, and
Clock Multiplier. The Reference bias is automatically enabled when any of the aforementioned peripherals are
enabled. The electrical specifications for the voltage reference and bias circuits are given in Table 6.1.
Important Note About the VREF Input: Port pin P0.7 is used as the external VREF input. When using an external
voltage reference, P0.7 should be configured as analog input and skipped by the Digital Crossbar. To configure P0.7
as analog input, set to ‘0’ Bit7 in register P0MDIN. To configure the Crossbar to skip P0.7, set to ‘1’ Bit7 in register
P0SKIP. Refer to
The temperature sensor connects to the ADC0 positive input multiplexer (see
page 40
the temperature sensor defaults to a high impedance state and any ADC0 measurements performed on the sensor
result in meaningless data.
VOLTAGE REFERENCE
for details). The TEMPE bit in register REF0CN enables/disables the temperature sensor. While disabled,
GND
VDD
R1
Section “14. Port Input/Output” on page 127
Reference
External
Voltage
Circuit
Figure 6.1. Voltage Reference Functional Block Diagram
VREF
VDD
REF0CN
0
1
TEMPE
Rev. 1.1
Reference
CLKMUL
REFBE
Internal
Enable
IOSCEN
AD0EN
EN
for complete Port I/O configuration details.
EN
EN
EN
Temp Sensor
Reference
Section “5.1. Analog Multiplexer” on
ADC Bias
Bias
C8051F320/1
To ADC,
Internal Oscillator
To Analog Mux
(to ADC)
To Clock Multiplier,
Temp Sensor
VREF
55