Browse Prior Art Database

RISC-1 DRIVER

IP.com Disclosure Number: IPCOM000006645D
Original Publication Date: 1992-Dec-01
Included in the Prior Art Database: 2002-Jan-18
Document File: 4 page(s) / 209K

Publishing Venue

Motorola

Related People

Jeffrey R. Halvorson: AUTHOR [+3]

Abstract

In the past, Bum-In and High Temperature over Operating Life (HTOL) Testing was performed by sequential down-loading of test code. This was done by A clock pulse that would be fed into a counter with a binary output of 13 lines. This has a total of 8,192 possi- ble addresses. The binary counter output was fed into EPROM's where the actual program would reside. The counters would start by presenting the address "Zero" to the EPROM and, in turn, the EPROM presents the data for that address to it's output. The counters count up in a contiguous manner until they reach their last address and roll over to the "Zero" address and con- tinue or until a reset signal is asserted. The EPROMs would output Code to the DUT's and a feedback signal from the DUT's were checked to verify: 1.) Did the code get accepted by the device? 2.) Did the device to acknowledge the instructions? 3.) Did the code put a programmable gate into an output low/high state? This method fails to truly verify operation of a CMMU. A CMMU cannot "obey" commands, it just routes Addresses and Data in a more efficient manner. This makes valid testing Cacheable Memory Manage- ment Units fairly diicult. In the past we checked a Bus Feedback pin (C2) with an osdloscope to make sure that it was a static high. If any part should have the signal 'C2' go low, all parts would permanently latch the status, until either the driver was Reset, or the Burn-In Cycle was ended. Because of this, it was necessary to create and develop the RISC-l Driver. A part could cat- astrophically fail and not put a low pulse on C2. Simply testing a device for a static signal is not a valid test for functionality of a device. These conditions could all occur and not identify a non-functional part.

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MOTOROLA INC. Technical Developments Volume 17 December 1992

RISC-l DRIVER

by Jeffrey R. Halvorson, Frederick D. Causey and Michael G. Green

  In the past, Bum-In and High Temperature over Operating Life (HTOL) Testing was performed by sequential down-loading of test code. This was done by A clock pulse that would be fed into a counter with a binary output of 13 lines. This has a total of 8,192 possi- ble addresses. The binary counter output was fed into EPROM's where the actual program would reside. The counters would start by presenting the address "Zero" to the EPROM and, in turn, the EPROM presents the data for that address to it's output. The counters count up in a contiguous manner until they reach their last address and roll over to the "Zero" address and con- tinue or until a reset signal is asserted. The EPROMs would output Code to the DUT's and a feedback signal from the DUT's were checked to verify:

1.) Did the code get accepted by the device?

2.) Did the device to acknowledge the instructions?

3.) Did the code put a programmable gate into an output low/high state?

  This method fails to truly verify operation of a CMMU. A CMMU cannot "obey" commands, it just routes Addresses and Data in a more efficient manner. This makes valid testing Cacheable Memory Manage- ment Units fairly diicult. In the past we checked a Bus Feedback pin (C2) with an osdloscope to make sure that it was a static high. If any part should have the signal 'C2' go low, all parts would permanently latch the status, until either the driver was Reset, or the Burn-In Cycle was ended. Because of this, it was necessary to create and develop the RISC-l Driver. A part could cat- astrophically fail and not put a low pulse on C2. Simply testing a device for a static signal is not a valid test for functionality of a device. These conditions could all occur and not identify a non-functional part.

  The RISC-l Driver is a collection of different technologies all working together to accomplish a goal that had been previously ignored. The technologies can be broken into three (3) separate entities. The modules

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are: the Circuit Breaker, RS-232 Serial Communications Ports, and the actual Test Logic Array.

  The tirst technology to explore is the Circuit Breaker. This Circuit Breaker is not the conventional, over the counter, slow acting type. It is an electronic modular component network that primarily contains Motorola's MC68HC811E2, an Operational Amplifier, a Charge Pump Circuit, a Field Effect Power Transistor (Power FET), and a precision O.OlQ 5 Watt Resistor.

  The MC68HC811E2 MCU was selected because of the features it offers. The software program that runs the Electronic Circuit Breaker in the MCU resides in the address area of the Electrically Erasable Read Only Memory (EEPROM). With this feature, the operating program is not lost when power is turned off and circuit board is stored but is still very flexible in case a software change is needed. Total Device Un...