MCS® 96 microcontrollers
General Information on CAN Devices
(includes comparison of 82526/82527)
This document briefly describes the CAN protocol and the general differences between the 82526 and the 82527 CAN devices. It also includes a list of the available technical literature, chip and tool availability, as well as the product schedules.
Q: What is CAN?
A: CAN stands for Controller Area Network and is a communications protocol developed and maintained by Robert Bosch, GmbH. The protocol is designed to manage multiplexed communications between multiple CPUs. It is control information oriented, uses non-destructive bit-wise arbitration to decide which node "owns" the bus, and has a message priority scheme based on the value of the message identifier transmitted with each message.
Q: What is the 82527 device?
A: The 82527 device is the first available implementation of the CAN protocol, Specification 2.0, and is a joint development of Robert Bosch, GmbH and the Intel Corporation.
The 82527 implements the contention-based 1 Mbit/sec CAN protocol, and incorporates powerful, built-in error checking capabilities. The 82527 has all error detection, correction and confinement capabilities on-chip, and thus allows the host controller to run its application tasks instead of communication processing and error handling tasks.
The 82527 transmits both 11- and 29-bit message identifiers as defined in CAN specification 2.0. This allows the 82527 to comply with the "J1939 Recommended Communications Practices" of the SAE Truck and Bus Control and Communications Network subcommittee. In addition, this CAN device serves high-speed networking applications using J1850 message types.
In 1989, Intel began full production of the 82526, the industry's first CAN communications controller. Intel's latest standalone CAN controller is the 82527 and is currently in production. The 82527 provides additional capability including CAN Specification 2.0 compatibility, more message objects (15 total) and more host-CPU interface modes. The 82527 will interface to Intel's 8 and 16-bit microcontrollers, Motorola's HC05, HC11, and 332, microcontrollers as well as other manufacturer's microcontrollers.
Q: Is the 82527 a replacement for the 82526?
A: The pinouts of the 82526 and the 82527 are nearly identical so that hardware modifications may not be significant. However, the devices have significant differences in how message objects are stored and in their control registers which will require substantial changes to the software. The major differences between the two devices are listed below.
Software
| 82526 |
82527 |
| The message objects are stored consecutively in RAM |
The message objects are stored in fixed locations in RAM |
| Standard 11-bit message IDs allowed |
Extended or Standard (29- or 11-bit) message IDs are allowed |
| There are no acceptance mask filters |
There are two acceptance mask filters |
| The message objects are not buffered |
One receive message object is buffered |
| The message object control bits require a read/modify/write to change |
The message object control bits can be modified with a single write instruction |
| Bit checking required to detect a CPU access |
No checking required for CPU accesses |
Hardware
| 82526 |
82527 |
| 8-bit multiplexed address/data bus |
8- and 16-bit multiplexed address/data bus (Intel)
8-bit multiplexed address/data bus (non-Intel)
8-bit non-multiplexed (sync and async)
SPI serial mode
|
| Programmable output |
Non-programmable output |
| No CPU interface pins |
Two CPU interface pins |
| 3 chip select output pins |
No chip select output pins |
| No VCC/2 output |
VCC/2 output |
Q: What literature is available on Intel CAN products?
A: The 82527 literature is available through our literature center now available on our Intel Web site at: http://developer.intel.com/design/litcentr/index.htm. Or, call 1-800-548-4725 and provide them with the literature order numbers you desire.
82527 Serial Communications Controller Datasheet 272250
82527 Serial Communications Controller Architectural Overview 272410
Introduction to the Controller Area Network (CAN) Protocol 270962
Automotive Products Handbook 231792
There are additional documents that provide you with application and product information on Intel's CAN products.
Application Note
App-Note: Interfacing a 68332 Microcontroller to an 82527
App-Note: Interfacing a MCS(R) 51 Microcontroller to an 82527
App-Note: Interfacing a 386EX Microprocessor to an 82527
App-Note: Interfacing a 20Mhz 8XC196 to an 82527
App-Note: Interfacing a 68HC11 to an 82527 CAN Controller
Website (same for all listed above)
http://developer.intel.com/design/auto/can/applnots
Q: Is there a controller that has a CAN integrated as a peripheral?
A: Yes, Intel offers two high-end 16-bit embedded microcontrollers with integrated CAN. These two products, the 87C196CA and 87C196CB were designed around the C196KX core. They provides a variety of real-time peripherals and integrated CAN networking capabilities.
A data sheet can be obtained by calling 1-800-548-4725 and requesting the data sheet: 87C196CA/87C196CB Advanced 16-bit Microcontroller with Integrated CAN 2.0. Order number 272405.
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