C8051F572-IMR Silicon Labs, C8051F572-IMR Datasheet - Page 169

• Manufacturer Part Number: C8051F572-IMR
• Description: 8-bit Microcontrollers - MCU 50 MIPS 16 kB 2 kB CAN2.0 LIN 2.1 SPI
• Manufacturer: Silicon Labs

Specifications of C8051F572-IMR

• Rohs: yes
• Core: 8051
• Data Bus Width: 8 bit
• Processor Series: C8051

19.1.3. Interfacing Port I/O in a Multi-Voltage System
All Port I/O are capable of interfacing to digital logic operating at a supply voltage higher than VDD and
less than 5.25 V. Connect the VIO pin to the voltage source of the interface logic.
19.2. Assigning Port I/O Pins to Analog and Digital Functions
Port I/O pins P0.0–P3.7 can be assigned to various analog, digital, and external interrupt functions. P4.0
can be assigned to only digital functions. The Port pins assigned to analog functions should be configured
for analog I/O, and Port pins assigned to digital or external interrupt functions should be configured for dig-
ital I/O.
19.2.1. Assigning Port I/O Pins to Analog Functions
Table 19.1 shows all available analog functions that require Port I/O assignments. Port pins selected for
these analog functions should have their corresponding bit in PnSKIP set to 1. This reserves the pin
for use by the analog function and does not allow it to be claimed by the Crossbar. Table 19.1 shows the
potential mapping of Port I/O to each analog function.
19.2.2. Assigning Port I/O Pins to Digital Functions
Any Port pins not assigned to analog functions may be assigned to digital functions or used as GPIO. Most
digital functions rely on the Crossbar for pin assignment; however, some digital functions bypass the
Crossbar in a manner similar to the analog functions listed above. Port pins used by these digital func-
tions and any Port pins selected for use as GPIO should have their corresponding bit in PnSKIP set
to 1. Table 19.2 shows all available digital functions and the potential mapping of Port I/O to each digital
function.
Analog Function
ADC Input
Comparator0 or Compartor1 Input
Voltage Reference (VREF0)
External Oscillator in Crystal Mode (XTAL1)
External Oscillator in RC, C, or Crystal Mode (XTAL2)
*Note: P3.1–P3.7 are available on the 40-pin packages. P2.2-P3.0 are available 40-pin and 32-pin packages.
Digital Function
UART0, SPI0, SMBus,
CAN0, LIN0, CP0, CP0A,
CP1, CP1A, SYSCLK, PCA0
(CEX0-5 and ECI), T0 or T1.
*Note: P3.1–P3.7 are available on the 40-pin packages. P2.2-P3.0 are available 40-pin and 32-pin packages.
Table 19.1. Port I/O Assignment for Analog Functions
Table 19.2. Port I/O Assignment for Digital Functions
Any Port pin available for assignment by the
Crossbar. This includes P0.0–P4.0* pins which
have their PnSKIP bit set to 0.
Note: The Crossbar will always assign UART0
pins to P0.4 and P0.5 and always assign CAN0
to P0.6 and P0.7.
Potentially Assignable Port Pins
Rev. 1.1
Potentially Assignable
P0.0–P3.7*
P0.0–P2.7*
Port Pins
C8051F55x/56x/57x
P0.0
P0.2
P0.3
XBR0, XBR1, XBR2
CPT0MX, CPT1MX,
OSCXCN, PnSKIP
OSCXCN, PnSKIP
ADC0MX, PnSKIP
REF0CN, PnSKIP
SFR(s) used for
SFR(s) used for
Assignment
Assignment
PnSKIP
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