programmable baud rate generator

Only some computers, e.g., the Sam- son 65, enable you to reprogram the ACIA (asynchronous communications interface adapter), or whatever your serial interface may be, if you want to connect a printer and a modem to your computer. With most other micros, you have to use an additional circuit like the one proposed here. The circuit is based on a presettable, synchronous down counter, a CMOS IC type 40103. Another CMOS IC, type 4060B, serves as a crystal con- trolled clock generator. The crystal fre- quency, fx, is 2.4576 MHz, while the clock, fc, is 153.6 kHz. The output frequency, fo, of the generator is determined from 5v programmable baud-rate generator ion O fo = [153.6/IN + 1)] kHz 10 STROBE 5V LS 153.6 kHz where N is the decimal equivalent of the number that is input to the J0...J7 terminals of the 40103 (see Al table). A2O The number Nis provided by the com- A30 puter and from there written into, and A40 12 N 13 04 1C3 CJ j MIN stored by, the 74LS374. The table gives various...