Keyboard testing methods and apparatus

Details Keyboard testing methods and apparatus Keyboard testing methods and apparatus

1991-10-16

1994-11-22

Teska, Kevin J.

Boots, shoes, and leggings

364481, 371 151, 395275, G06F 1122, G06F 1520

Patent

active

053674723

ABSTRACT:
An IBM PC compatible keyboard is provided which, on power-up, does not access the keyboard LEDs until receiving a command from the host computer. When the keyboard controller performs a Basic Assurance Test (BAT) on power-up before receiving a host command, the controller does not turn on the LEDs. Upon receiving a Reset command from the host, the controller: (1) turns on the LEDs and performs a BAT with LEDs on; and (2) flashes the LEDs a second time to be compatible with the IBM PCs. Another feature of the invention is a non-destructive test of the controller RAM during BATs. The RAM is tested non-destructively both for the "stuck-at-1" and the "stuck-at-0" conditions. Still another feature is that the controller determines the state of the keyboard LEDs without reading a hardware port. The controller keeps track of the LED state by flags in the controller memory, and the controller determines the LED state by reading the flags.

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COP680C/COP681C/COP880C/COP881C/COP980C/COP981C Microcontrollers, (National Semiconductor Corporation, Jun. 1991), pp. 1-24.
MF2 Compatible Keyboard with COP8 Microcontrollers, (National Semiconductor Corporation, Feb. 1991), pp. 1-20.
IBM Personal System/2.RTM. Hardware Interface Technical Reference (First Edition, May 1988), chapter "Keyboards (101- and 102-Key)," pp. 19-22.
COP8 Microcontroller Development Support. Duplicator Board Instruction Manual (National Semiconductor Corporation, Mar. 1991, NCS Publication Number 420421256-001).

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