[hpsdr] dumb diversity questions of the day

[Joe Martin K5SO]

Hi Frank,

The Mercury board logical addressing is independent of which board is  
master or slave.   "Master" and "Slave" only denotes which board is  
supplying the 122.88 MHz for the two boards.  Either one may be  
logical "0" or logical "1", as set by the jumper(s) on the GPIO header  
J5.

The logical addressing scheme for J5 on Mercury is described on the  
Wiki at: http://openhpsdr.org/wiki/index.php?title=Multi-Receiver

The pertinent section from that page to answer your addressing  
question is copied below:

> Each Mercury board must have jumpers in place to specify an address  
> for the board. Each board will have a different jumper-selected  
> address. The address is specified by placing jumpers on J5 (GPIO  
> pins) on the Mercury board. Looking at the Mercury board with the  
> Atlas bus connector down, the GPIO pins on J5 are arranged such that  
> the lowest pair of pins (closest to F1) are GPIO pins 1,0. Without a  
> jumper, the logic value for the GPIO pin pair is "0", with a jumper  
> across the pins the logic value is "1". The Mercury board address is  
> specified as a 3-bit address according to the jumpers placed on J5.  
> The GPIO pins on J5 are assigned as follows:
> GPIO pairs:
> 9,8 = Mercury ID bit 2,
> 7,6 = Mercury ID bit 1,
> 5,4 = Mercury ID bit 0,
>
> 1) The address of the first Mercury board should be "000", selected  
> by having no jumpers on GPIO pins 9-8, 7-6, or 5-4. The address of  
> the second Mercury board should be "001", selected by having a  
> jumper on GPIO pins 5-4; and so on for any additional Mercury boards  
> present.
> Therefore, for dual Mercury boards, the 3,2 GPIO jumper pair should  
> be on both Mercury cards, the first Mercury board is set for Merc_ID  
> = 000 (no jumpers on pins 9-8, 7-6, or 5-4) and the 2nd Mercury card  
> is set for Merc_ID = 001 (a jumper across the 5,4 pair).


When running only two Mercury boards (Mercury 1 and Mercury 2), one  
will be addressed as logical "0" (this is board is then Mercury 1 as  
far as PowerSDR is concerned) and one will be addressed as logical  
"1" (this board is then Mercury 2 for PowerSDR).

The logical "0" board (Mercury 1) will have no jumpers on J5.  The  
logical "1" board (Mercury 2) will have a single jumper across pins  
5,4 of J5.

73,  Joe K5SO


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