EB203

www.DataSheet4U.com EB203 Test Bus Controller SN74ACT8990 Author Peter Forstner Date: 01.07.92 Rev.: 1.0 TEXAS INSTRUMENTS This report describes the IEEE 1149.1 Test Bus Controller SN74ACT8990 from Texas Instruments. The first part explains the architecture and operation of the Test Bus Controller; the second part uses examples to explain the programming procedure. www.DataSheet4U.com 2 EB203 TEXAS INSTRUMENTS Contents: Contents: 1. Introduction................................................................................................ 5 2. Hardware .................................................................................................... 8 2.1. The Processor Interface................................................................... 8 2.2. The Test Bus Interface................................................................... 10 2.3. Architecture.................................................................................... 13 2.3.1. SEQUENCE BLOCK........................................................... 13 2.3.2. SERIAL BLOCK.................................................................. 15 2.3.3. EVENT BLOCK................................................................... 17 2.3.4. COUNTER BLOCK............................................................. 21 2.3.5. COMMAND BLOCK............................................................ 22 2.3.6. HOST BLOCK..................................................................... 23 3. Pro...