This posting will deal with the hardware connections necessary for getting a 28X up and running as a dual output stage desulfator with a dedendriting circuit.
www.rev-ed.co.uk/docs/axe001_xparts.pdf
This assumes running the pulser on a 12V battery. A TO-220 socket is specified for the crystal, in order that you can run the 28X at any of the current clock frequencies by using either a 4Mhz, 8Mhz or 16Mhz resonator. A 16Mhz resonator will be used for pulsing purposes.
In lieu of a TO-220 socket a piece of SIP or DIP sockets for IC's can be used to hold the crystal instead.
7805:
From the 12V positive, through a diode, through a 1000uF inductor, to the 7805 input pin. The input pin also has a 0.1uF and 100uF electrolytic to ground. The 7805 ouput has a 0.1uF cap to ground.
7805 output through a SPST switch to pin 20 of the 28X.
PICAXE 28X
PICAXE Pin 1 (Reset) Must have a 4.7K pull up resistor to the +5 volt rail. A reset switch from pin 1 to ground is recommended. Failure to pull up the reset pin results in the PICAXE refusing to download a program.
PICAXE pin 2 (Analog Input 0) through a 1K resistor, through a 50K NTC thermistor (ambient air sensor) to ground. The 1K/50K junction should have a 51K resistor to +5V
PICAXE pin 3 (Analog Input 1) through a 1K resistor, through a 50K NTC thermistor (FET sensor) to ground. The 1K/50K junction should have a 51K resistor to +5V
PICAXE pin 4 (Analog Input 2) NC
PICAXE pin 5 (Analog Input 3) NC
PICAXE pin 6 (Serial In) through a 22k resistor to pin 3 of a RS-232, 9 pin female connector. A 10K resistor from RS232, pin 3 to ground.
PICAXE pin 7 (Serial Out) to pin 2 of a RS-232, 9 pin female connector
PICAXE pin8 (0V) to ground and to the middle pin of a TO-220 socket
PICAXE pin 9 (Resonator) to one end of a TO-220 socket
PICAXE pin 10 (Resonator) to the other end of a TO-220 socket
PICAXE pins 11 through 18 (Digital INputs, 0 to 7) should each have a 10K resistor to ground
NOTE: A 0.10uF cap should be used between pins 19 and 20
PICAXE pin 19 (Ground or 0V)
PICAXE pin 20 (+5 or +V)
PICAXE pins 21 to 28 (Outputs)
--pin 28 (Output 7) to NFET gate (output stage)
--pin 27 (Output 6) to NFET gate (output stage)
--pin 26 (Output 5) NC
--pin 25 (Output 4) NC
--pin 24 (Output 3) NC
--pin 23 (Output 2) to NFET gate (Dedendriting)
--pin 22 (Output 1) through 330 ohm R to Piezo buzzer to ground, 5.1V zener in parallel with buzzer
--pin 21 (Output 0) through 330 ohm R to Pulsing Activity LED
www.rev-ed.co.uk/docs/axe001_xparts.pdf
This assumes running the pulser on a 12V battery. A TO-220 socket is specified for the crystal, in order that you can run the 28X at any of the current clock frequencies by using either a 4Mhz, 8Mhz or 16Mhz resonator. A 16Mhz resonator will be used for pulsing purposes.
In lieu of a TO-220 socket a piece of SIP or DIP sockets for IC's can be used to hold the crystal instead.
7805:
From the 12V positive, through a diode, through a 1000uF inductor, to the 7805 input pin. The input pin also has a 0.1uF and 100uF electrolytic to ground. The 7805 ouput has a 0.1uF cap to ground.
7805 output through a SPST switch to pin 20 of the 28X.
PICAXE 28X
PICAXE Pin 1 (Reset) Must have a 4.7K pull up resistor to the +5 volt rail. A reset switch from pin 1 to ground is recommended. Failure to pull up the reset pin results in the PICAXE refusing to download a program.
PICAXE pin 2 (Analog Input 0) through a 1K resistor, through a 50K NTC thermistor (ambient air sensor) to ground. The 1K/50K junction should have a 51K resistor to +5V
PICAXE pin 3 (Analog Input 1) through a 1K resistor, through a 50K NTC thermistor (FET sensor) to ground. The 1K/50K junction should have a 51K resistor to +5V
PICAXE pin 4 (Analog Input 2) NC
PICAXE pin 5 (Analog Input 3) NC
PICAXE pin 6 (Serial In) through a 22k resistor to pin 3 of a RS-232, 9 pin female connector. A 10K resistor from RS232, pin 3 to ground.
PICAXE pin 7 (Serial Out) to pin 2 of a RS-232, 9 pin female connector
PICAXE pin8 (0V) to ground and to the middle pin of a TO-220 socket
PICAXE pin 9 (Resonator) to one end of a TO-220 socket
PICAXE pin 10 (Resonator) to the other end of a TO-220 socket
PICAXE pins 11 through 18 (Digital INputs, 0 to 7) should each have a 10K resistor to ground
NOTE: A 0.10uF cap should be used between pins 19 and 20
PICAXE pin 19 (Ground or 0V)
PICAXE pin 20 (+5 or +V)
PICAXE pins 21 to 28 (Outputs)
--pin 28 (Output 7) to NFET gate (output stage)
--pin 27 (Output 6) to NFET gate (output stage)
--pin 26 (Output 5) NC
--pin 25 (Output 4) NC
--pin 24 (Output 3) NC
--pin 23 (Output 2) to NFET gate (Dedendriting)
--pin 22 (Output 1) through 330 ohm R to Piezo buzzer to ground, 5.1V zener in parallel with buzzer
--pin 21 (Output 0) through 330 ohm R to Pulsing Activity LED
