Electronic Design

Microcontroller Families Integrate CAN And LIN Interfaces

Controller Area Network (CAN) and Local Interconnect Network (LIN) are quickly becoming the automotive industry's control networks of choice. Mi-crochip Technology's PIC18Cx58 and PIC-16C43x microcontrollers target this market with integrated CAN and LIN interfaces that keep costs down while improving integration and performance. Combining the microcontrol unit (MCU) with the network interface trims the hardware footprint and improves reliability.

CAN handles communication tasks for engine control, navigation systems, and other functions. Used extensively in industrial control applications such as medical instruments, robotics, and motor control, it supports distributed master nodes. LIN is a low-cost, master/slave architecture for short distances, like the space within a car door. Its slow speed of up to 20 kbits/s is enough for most basic control needs.

The 68-pin PIC18C658 and 84-pin PIC18C858 incorporate CAN 2.0B interfaces. CAN operates at 1 Mbit/s over two wires. The 18-pin PIC-16C432-I/SS and 20-pin PIC-16C433-I/SO have LIN interfaces that operate at 20 kbits/s over one wire.

Both PIC18Cx58 models include 1536 bytes of RAM. Also, the MCUs include 16 kwords of one-time-programmable (OTP) memory. The program memory is written using Microchip's In-Circuit Serial Programming (ICSP) technology. ICSP uses only two I/O pins. Designers, then, can program the MCU after the chip has been installed.

The CAN interface supports two priority levels, two acceptance masks, and six acceptance filters. Its receiver is double buffered. Furthermore, the chip supports programmable wake-up for power-consumption management. It has a self-test programmable loopback mode, too.

Additional peripherals include a 9-bit addressable RS-485 USART, I2C and SPI support, a selectable oscillator, and a pair of capture/compare/PWM modules. The MCU includes a number of 8- and 16-bit timers with 52 or 68 bidirectional I/O ports. It has a 10-bit ADC, two comparators with a programmable voltage reference, and low-voltage protection and programmable brownout detection circuitry.

The PIC18Cx58 family works with Microchip's MPLAB-ICE 2000 universal in-circuit emulator (ICE). This device can emulate voltages as low as 2.0 V. Its integrated development environment runs on Windows. The MPLAB-ICE 2000 starts at $1995 each. C compilers and other development tools cost extra.

The PIC16C432-I/SS and PIC-16C433-I/SO include 2 kwords of OTP program memory and 128 bytes of RAM. Their 14-bit instructions execute in one cycle, except for the two-cycle branch instructions. The MCU program memory supports Microchip's ICSP programming technology.

A four-channel, 8-bit ADC is included. So are 8-bit timers, a watchdog timer with its own on-chip RC oscillator, and a power-up timer. The MCU supports a sleep mode, wake-on bus activity, and power-on reset.

The 68-pin PIC18C658 costs $7.35, the 84-pin PIC18C858 costs $8.08, the PIC16C432-I/SS costs $2.46, and the PIC16C433-I/SO costs $2.31. Flash-memory versions will be available later this year.

Microchip Technology Inc., 2355 West Chandler Blvd., Chandler, AZ 85224-6199; (480) 786-7200; fax (480) 889-9210; www.microchip.com.

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