About Reset Warning. ------------------- This feature is available on some A1000 and A2000 keyboards. You cannot rely on this feature for all Amigas. The keyboard has the additional task of resetting the computer on the command of the user. The user initiates Reset Warning by simultaneously pressing the Ctrl key and the two Amiga keys. The keyboard responds to this input by syncing up any pending transmit operations. The keyboard then sends a "reset warning" to the Amiga. This action alerts the Amiga software to finish up any pending operations (such as disk DMA) and prepare for reset. A specific sequence of operations ensure that the Amiga is in a state where it can respond to the reset warning. The keyboard sends two actual "reset warning" keycodes. The Amiga must handshake to the first code like any normal keystroke, else the keyboard goes directly to Hard Reset . On the second "reset warning" code the Amiga must drive KDAT low within 250 milliseconds, else the keyboard goes directly to Hard Reset . If all the tests are passed, the Amiga has 10 full seconds to do emergency processing. When the Amiga pulls KDAT high again, the keyboard finally asserts hard reset . If the Amiga fails to pull KDAT high within 10 seconds, Hard Reset is asserted anyway.
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