SECTION 1INTRODUCTION The byte data link controller (BDLC) module is a serial communication module which allows the user to send and receive messages across a Society of Automotive Engineers (SAE) J1850 serial communication network. The user’s software handles each transmitted or received message on a byte-by-byte basis, while the BDLC performs all of the network access, arbitration, message framing and error detection duties. This document is intended as an aid for developing the software for using the BDLC module to perform SAE J1850 communication. As such, it provides an implementation- independant description of the operation of the BDLC. Because some implementations of the BDLC may provide enhanced capabilites, it is strongly recommended that you refer to the BDLC module specification included in the MCU specification of the device you are using for a detailed hardware description. This guide is also not intended as a tutorial on the SAE J1850 protocol. This document assumes the reader is familiar with the requirements and operation of the SAE J1850 protocol, as specified in the document SAE Standard J1850 Class B Data Communication Network Interface . For more detailed information on the SAE J1850 protocol, refer to the applicable SAE documents. 1.1 BDLC Features Features of the BDLC module include: • SAE J1850 compatible • 10.4 kbps variable pulse width (VPW) modulation format • Digital noise filter • Collision detection • Hardware cyclical redundancy check (CRC) generation and checking • Two power saving modes with automatic wake up on network activity • Polling and CPU interrupts with vector lookup available • Receive and transmit block mode supported • Supports 4X receive mode (41.6 kbps) • Digital and Analog loopback modes • In-frame response (IFR) types 0, 1, 2, and 3 supported • Dedicated register for symbol timing adjustments 1.2 General The BDLC consists of three functional blocks: • The CPU interface block • The protocol handler block • The MUX interface block Figure 1-1 displays a block diagram of the BDLC. 中国最大的欧亿·体育（中国）有限公司库下