Difference between revisions of "National Semiconductor NS405 and NS455 Terminal Management Processor"
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The NS455 has [[firmware]] in the internal ROM; an input pin allows selection of either this, or code in an external ROM. The NS405 is the same chip, but for use with external ROM only. (The internal ROM is still present, but the contents are unknown.) | The NS455 has [[firmware]] in the internal ROM; an input pin allows selection of either this, or code in an external ROM. The NS405 is the same chip, but for use with external ROM only. (The internal ROM is still present, but the contents are unknown.) | ||
| − | The CPU is based on the [[8048]]-series [[microcontroller]]s. The chip includes most of what is needed for a terminal: e.g. a clock, | + | The CPU is based on the [[8048]]-series [[microcontroller]]s. The chip includes most of what is needed for a terminal: e.g. the [[CRT]] controller, a [[character generator]], clock, [[Asynchronous serial line#UART|UART]], etc. External [[level converter]]s for [[EIA RS-232 serial line interface#Electrical|EIA]] signal levels are required, as is [[Random Access Memory|RAM]] to hold the screen contents, though. |
==External link== | ==External link== | ||
* [http://bitsavers.trailing-edge.com/pdf/zentec/Zentec_ADM3_Retrofit/NS405.pdf NS405 data sheet] | * [http://bitsavers.trailing-edge.com/pdf/zentec/Zentec_ADM3_Retrofit/NS405.pdf NS405 data sheet] | ||
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| + | [[Category: Integrated Circuits]] | ||
Latest revision as of 04:42, 27 February 2023
The NS405 and NS455 Terminal Management Processor chips from National Semiconductor provide complete video terminal functionality, including a CPU which can use either internal or external ROM.
The NS455 has firmware in the internal ROM; an input pin allows selection of either this, or code in an external ROM. The NS405 is the same chip, but for use with external ROM only. (The internal ROM is still present, but the contents are unknown.)
The CPU is based on the 8048-series microcontrollers. The chip includes most of what is needed for a terminal: e.g. the CRT controller, a character generator, clock, UART, etc. External level converters for EIA signal levels are required, as is RAM to hold the screen contents, though.
