My journey with ATTiny4313 (part 4)
Part 4: Dealing with interrupts Managing the /STROBE line The protocol between the driver and the Soundpool MO4 The communication between the Atari and the Soundpool MO4 is achieved via the parallel port (or printer port, sometimes called "Centronics") and a specific driver ; I've already detailed the connection in this article . What is /STROBE used for? Since the parallel port is asynchronous, /STROBE is used to warn the MO4 that a new byte is available. But /STROBE is also used to reset the MO4 when it is pulsed 4 times in a row. In response, BUSY is expected to be high in less than 2 micro-second. The reset is requested when the driver starts, and after a bunch of data has been sent. The driver always send data to the 4 outputs of the MO4, from output 1 to 4: for each output, one byte is sent to indicate how many bytes will follow for this output, then the data bytes: Send data to the MO4: Send data for output 1 Write the quantity of
