How do I connect the POL SEL A0 and POL SEL A1 inputs?
A. Each of the POL SEL input signals should either be left unconnected (these signals are pulled up internally) or grounded. The POL SEL signals only effect 16- and 32-bit transfers to and from the DD-42900. They do not affect the addressing of 8-bit control or status registers. The POL SEL A0 is only used when the DD-42900 is operated in 8-bit mode. When the DD-42900 is operated in 16-bit mode, the POL SEL A0 must be connected to ground. The POL SEL A0 controls the order in which the high and low order bytes of a (16-bit) word are written to and read from the DD-42900. When POL SEL A0 is a logic one then the high order byte of a word is written in address X and the low order byte is written in address X+1. This is the scheme typically employed by Motorola processors. When POL SEL A0 is a logic zero then the low order byte of a word is written in address X and the high order byte is written in address X+1. This is the scheme typically employed by Intel processors.
