<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi Frank, <div><br></div><div>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. </div><div><br></div><div>The logical addressing scheme for J5 on Mercury is described on the Wiki at: <a href="http://openhpsdr.org/wiki/index.php?title=Multi-Receiver">http://openhpsdr.org/wiki/index.php?title=Multi-Receiver</a></div><div><br></div><div>The pertinent section from that page to answer your addressing question is copied below:</div><div><br></div><div><blockquote type="cite"><span class="Apple-style-span" style="font-family: sans-serif; font-size: 13px; line-height: 19px; "><div style="margin-top: 0.4em; margin-right: 0px; margin-bottom: 0.5em; margin-left: 0px; line-height: 1.5em; ">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:</div><div style="margin-top: 0.4em; margin-right: 0px; margin-bottom: 0.5em; margin-left: 0px; line-height: 1.5em; ">GPIO pairs:</div><div style="margin-top: 0.4em; margin-right: 0px; margin-bottom: 0.5em; margin-left: 0px; line-height: 1.5em; ">9,8 = Mercury ID bit 2,</div><div style="margin-top: 0.4em; margin-right: 0px; margin-bottom: 0.5em; margin-left: 0px; line-height: 1.5em; ">7,6 = Mercury ID bit 1,</div><div style="margin-top: 0.4em; margin-right: 0px; margin-bottom: 0.5em; margin-left: 0px; line-height: 1.5em; ">5,4 = Mercury ID bit 0,</div><div style="margin-top: 0.4em; margin-right: 0px; margin-bottom: 0.5em; margin-left: 0px; line-height: 1.5em; "><br>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.</div><div style="margin-top: 0.4em; margin-right: 0px; margin-bottom: 0.5em; margin-left: 0px; line-height: 1.5em; ">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).</div></span></blockquote></div><div><span class="Apple-style-span" style="font-family: sans-serif; font-size: 13px; line-height: 19px; "><div style="margin-top: 0.4em; margin-right: 0px; margin-bottom: 0.5em; margin-left: 0px; line-height: 1.5em; "><br></div><div style="margin-top: 0.4em; margin-right: 0px; margin-bottom: 0.5em; margin-left: 0px; line-height: 1.5em; ">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). </div><div style="margin-top: 0.4em; margin-right: 0px; margin-bottom: 0.5em; margin-left: 0px; line-height: 1.5em; "><br></div><div style="margin-top: 0.4em; margin-right: 0px; margin-bottom: 0.5em; margin-left: 0px; line-height: 1.5em; ">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. </div><div style="margin-top: 0.4em; margin-right: 0px; margin-bottom: 0.5em; margin-left: 0px; line-height: 1.5em; "><br></div><div style="margin-top: 0.4em; margin-right: 0px; margin-bottom: 0.5em; margin-left: 0px; line-height: 1.5em; ">73, Joe K5SO</div><div style="margin-top: 0.4em; margin-right: 0px; margin-bottom: 0.5em; margin-left: 0px; line-height: 1.5em; "><br></div></span></div><div><div><div><br></div></div></div></body></html>