DSP-10 User's Manual

Chapter 5 - The Users View of DSP-10 Hardware

This section assumes that you have a working DSP-10 board connected to the Analog Devices EZ-Kit Lite. This manual does not cover the assembly and initial testing of the DSP-10 hardware.

Connections to the DSP-10 - The schematics for the standard hardware connections are in the October 1999 part of the DSP-10 QST article . The following adds some comments and is a checklist for these connections:

POWER - Power of 11 to 16 Volts at 750 mA is required. This is connected to the 5.5/2.1 mm power connector with the center pin positive.

ANTENNA - An antenna for 2 meters or a transverter for other frequencies is connected tor the BNC connector on the front panel. Assuming that internal T/R switching is being used, there should be a 50 Ohm jumper (Phono connectors) between the transmitter output and the transmit side of the RF T/R switch.

SERIAL PORT - Communication between the transceiver and the PC is through the serial port at 9600 Baud, 8N1. A standard serial cable connects from the DB9 connector on the transceiver to a serial port on the PC.

MICROPHONE - The microphone uses a 5 pin DIN plug. Pins are:

  1  Audio 
  2  Ground 
  3  Not Used 
  4  Ground to transmit (PTT) 
  5  Ground

These connections are compatible with a Radio Shack 21-1172D hand-held mike.

CW KEY - No electronic keying is available. The jack takes a 1/8 inch plug. In addition, the right-hand Alt key can be used as an emergency CW key. Of course, for most purposes CW can be sent by typing on the PC keyboard.

SPEAKERS - This comes to a stereo 1/8 inch jack. The tip is left channel and the ring is right. Speakers down to 4 Ohms can be driven.

SEND/RECEIVE - The PTT on the microphone is available in all modes. More convenient for CW is the Home key on the PC. It toggles between Send and Receive.

ACCESSORY CONNECTOR - This 8 pin connector is primarily to control external amplifiers or transverters. The connections are:

 1  Power Amp on, +5 logic for on 
 2  Antenna Relay Control, +5 logic for transmit 
 3  E1 spare control 
 4  E2 spare control 
 5  E3 spare control 
 6  Ground 
 7  Not Used 
 8  +5 Volts for accessories, 100 mA max

Note that the antenna relay, power amplifier control and the internal transceiver signal generation are all sequenced in software.

T/R Sequencing - This is in software and discussed in Chapter 4 .

10 MHZ EXTERNAL REFERENCE - An internal 10 MHz reference oscillator is available for stand-alone use. It is also possible to phase-lock the synthesizers to an external 10 MHz reference by use of this input. Internally a jumper must be removed from pins 1 and 2 of P106 and the coax from the reference input must be connected to P106, ground to pin 3 and the center conductor to pin 2. This input goes directly to a CMOS device and the input should range from at least 1.5 to 3.5 Volts, but not more than 0.0 to 5.0 Volts. If using a sine wave external reference a small capacitor (a 0.01uF disc ceramic is satisfactory) should be installed in series with the 10 MHz line.

Fast Push-to-Talk is implemented in the PC and DSP software.  Configuration and hardware modifications required are:

  a-Change UHFA.CFG configuration file item hardware_ptt to 1
(from 0) 
  b-RS232 connector on DSP-10 (J201), remove wire
at p7 and tape 
  c-RS232 wire at p8 moves to p9 
  d-RS232 jumper p7 to p8 
  e-On the EZ-Kit PC board, cut the connection on U5 between
pins 9 and 10 (an Exacto knife does it) 
  f-In EZ-Kit box, run a wire from U5-pin 10 to C208.

What this does is to take the PTT logic level at C208, run it through the RS232 level converter (EZ-Kit U5) to the Ring Indicator line on the RS232 plug (pin 9). If the configuration file variable hardware_ptt has the value 1 this line will indicate PTT to the PC program.

Birdies - The old 5 kHz Birdie is gone, by a DSP software change. Many thanks to Hannes, SM6PGP who identified the source of the 5 kHz spur as being the reference output (pin 3) of the MC145170 PLL. I had accidentally left it active, as a divide by 16, and the resulting 625 KHz signal was somehow mixing and producing a signal at 19.665 MHz (our I-F). The 625 signal is not used, and it has now been programmed off.

If you are seeing an internally generated signal at 5 KHz intervals, it is not normal. This may be generated in the hardware PLL, since the reference frequency for the first LO is 5 KHz.

PC to DSP Commands - A summary of the commands, sent from the PC to the DSP, is available on the Internet. This is not needed to operate the DSP-10, but is for those wanting to use the existing DSP program with alternate control programs. This is linked from the DSP-10 homesite .

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