At 03:10 PM 5/9/2008, you wrote: >Sorry, Cecil, that's a bit too brief for me. Sorry, but I barely speak >english - BCD and binary don't come very naturally. The code I need for 28 >MHx, for example, is 1101. How does what you describe produce that? > >73, Pete N4ZR
The crystal board with V2.5 software uses 4 bit switch to select the group and individual frequency within the previously selected group, so some bits do double duty. When bit 3 is active it makes the software look a bits 0,1,2 as band setting switches, it then remember the group you have selected until you change it again by pushing on the button connected to bit 3. When the button on bit 3 is not pushed the PIC looks at switches 0,1,2 as bits that determine which of eight possible frequencies in the previously select group is active. Bit 3 determines if the other three bits (0 through 7) represents frequency or group information so typical use is as follows; You rotate your switch to the group of choice (groups 0 through 7) You push the button that is hooked to bit 3 of the PIC then you let it go, that sets the group of frequencies, and the PIC remembers it. Now you can use the rotary switch to select one of eight frequencies in that group, with this scheme if you had enough free EEPROM you could implement 64 frequencies, or 8 groups with eight choices each. So with a 74HC147 you would have some kind of rotary switch pick positions 0 through 7, the output of the 74HC147 is connected to bits 0, 1, and 2 of the PIC, you would also have a push button hooked up to bit 3 of the PIC. If however you are going to re-program the PIC then all bets are off and the scheme will be whatever you choose, but the above scheme is pretty flexible and gives you lot's of choices and it's already programmed in the device. I hope that makes it clear. Cecil K5NWA www.softrockradio.org www.qrpradio.com "Blessed are the cracked, for they shall let in the light."
