<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px">Since the announcement of the Hermes project there has been quiet a bit of traffic ‘in the background’, in summary the hardware details are now reasonably stable. What follows are some snippets of traffic to provide readers with some insight to the development process ......</span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><span style="letter-spacing: 0.0px"></span><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px">Phil VK6APH has provided several suggestions, namely:</span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><span style="letter-spacing: 0.0px"></span><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px"><i>There needs to be an audio out from the TLV320.</i></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px"><i>JTAG - the JTAG programming can come from the FX2, perhaps we have a</i></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px"><i>standard JTAG header and jumpers to connect the relevant pins on the FX2</i></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px"><i>so we can use either?</i></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px"><i>Need to show the LPF at the RF input.</i></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px"><i>We could take the forward power from the 15w PA as well since I think</i></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px"><i>there are enough spare inputs to read all we need.</i></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px"><i>ICD header needs to connect to ADC78H90.</i></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px"><i>If there are spare inputs should we bring them out - perhaps for use with an external amplifier etc?</i></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px"><i>122.88MHz clock directly feeds DAC.</i></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px"><i>Phil is also trying to find a packaged LPF so we can get rid of the toroids on</i></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px"><i>the DAC output.</i></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px"><i>Add a header for I2C signals from the FX2 to control external equipment.</i></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><span style="letter-spacing: 0.0px"></span><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px">Graham KE9H has made an interesting suggestion regarding the gain distribution of the existing Penelope 1/2 W PA strip :</span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><span style="letter-spacing: 0.0px"></span><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px"><i>As far as the gain re-distribution to get the transmit frequency response flat out to</i></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px"><i>50 MHz, you basically change the transformer T3 from a TC4-1T to a TC1-1T</i></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px"><i>(which will maximize linearity of the AD9744,) and add a second OPA2674</i></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px"><i>in series with the current OPA2674 OpAmp, and redistribute the gain between them.</i></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px"><i>The current OPA2674 is being run at 24 dB gain, and is hitting gain-bandwidth</i></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px"><i>limits around 30 MHz. With two in series, they would each be set for around</i></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px"><i>12 dB gain, and the combination should be flat well over 60 MHz. </i></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><span style="letter-spacing: 0.0px"></span><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px">Graham is also investigating the use of a THS6012 as a substitute PA, this provided a very clean output, at a higher level, a test board has been drafted and a few boards have been ordered to enable to testing. I’m not sure this chip will form part of Hermes as the supply requirements are beyond the current spec, but I guess the final decision will be made once the test results are in :)</span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><span style="letter-spacing: 0.0px"></span><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px">While I’m discussing the PA strip, I must reiterate that the PennyWhistle PA is really just a dream for Hermes, I really don’t think there will be enough room on the board, however I will squeeze everything one first, and if there is room, PennyWhistle will be considered.</span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><span style="letter-spacing: 0.0px"></span><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px">Graham has also suggested some form of audio PA be included, this has now been added to the hardware block diagram.</span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><span style="letter-spacing: 0.0px"></span><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px">Scotty WA2DFI, has made several suggestions and between us we have now settled on some of the connecting hardware. To save board edge space a number of the connectors are now ‘stack’ connectors. Scotty has also made a good start on the schematics, I’m not going to provide a guesstimate for release for comment, mainly due to Scotties Dayton commitments, but it’s going to be weeks not months :)</span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><span style="letter-spacing: 0.0px"></span><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px">Phil N8VB has provided some valuable information, namely:</span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><span style="letter-spacing: 0.0px"><i></i></span><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px"><i>Take a look at how I connect the FX2 to the FPGA using port E for 8 bit parallel configuration. After configuration I use this as the 8 bit communications bus between the FX2 and the FPGA. This allows faster configuration of the FPGA and faster read/writing to the registers in the FPGA (especially for tuning word). You might want to use this scheme in Hermes.</i></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><span style="letter-spacing: 0.0px"><i></i></span><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px"><i>Also, instead of using an Altera configuration device (especially for the larger '40 Cyclone III), consider using a SD card which can have a serial interface to the FX2. The FX2 can read the SD card and configure the FPGA via the parallel mode mentioned above.</i></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><span style="letter-spacing: 0.0px"></span><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px">Phil’s advice regarding the use of port E will be incorporated in Hermes. The move to an SD card is still in the balance as board real-estate is of a premium and I don’t understand / can’t see any benefits for the change? Can someone out there enlighten me?</span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><span style="letter-spacing: 0.0px"></span><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px">Phil N8VB, has also enlightened me on capability of the FX2 (although I’ve had to delve into the technical reference and ‘Google’ to ‘partially’ understand USB end points):</span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><span style="letter-spacing: 0.0px"></span><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px"><i>The FX2 has 4 high speed endpoints. This is enough for full duplex operation of the receiver and transmitter via USB.</i> </span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><span style="letter-spacing: 0.0px"></span><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px">The current command and control scheme will need to be restructured to achieve this and is well worth pursuing.</span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><span style="letter-spacing: 0.0px"></span><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px">Well I guess that pretty well brings everyone up to date with the Hermes story so far, so in summary, the hardware is close to being finalized, Scotty has made a start on the schematics, and I’m climbing the learning curve of OrCAD, in preparation to layout the board :)</span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><span style="letter-spacing: 0.0px"></span><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; "><span style="letter-spacing: 0.0px">Kevin - M0KHZ</span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><span style="letter-spacing: 0.0px"></span><br></div></body></html>