High speed print routine - for SC/MP

The use of the small circuit described here together with the output routine in table 1, enables the high-speed printing of information from the SC/MP. With the aid of the Elektor terminal, data can be displayed on the screen at a rate of 19200 baud. In effect this means that a 4K "string" which would normally take 38 seconds to print (at 1200 baud) can now be dis- played in approximately 2.5 seconds. display on a VDU at approximately this speed. In practice the 74LS373 is used in this circuit as a latch and three stage output buffer. The data on the SC/MP bus is latched when the decoding address (in this case 0800 ... 09FF) and the NWDS are at logic 0. Simul- taneously to this, because the software controlled Flag 2 is at logic 1, a pulse (between 0 ... 5 V) is latched. As a result of all this, the UART of the Elektor terminal, is brought into tri- state operation, and the data in the latch is transferred into the output buffer of the 74LS373. The outputs of IC1 and Flag 2 are co...