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Embedded Systems, Publishers

DonTronics - DT106


dt106bov.jpg (30944 bytes) dt106bl1.jpg (12521 bytes)


The New DT106B SimmStick:

Appears the PIC16F876 will not be available from MicroChip until around Dec-99

dt106bct.pdf This is the schematic in PDF format, about 30K long.

We have put a 485 footprint over the 232 chip, 40 pin header is pin compatible with chip, so you would need to solder header on the solder side for an emulator pod.

28, and 40 pin footprints to suit all current PICmicro flash PIC1687x devices.
Alternative RS-232 or RS-485 Comms
78L05 Regulator
Eeprom. Same pinout for MicroChip 24LCxx family.
8570 Ram. can be used as second Eeprom location.
Provision for power up/reset circuit which allows both a cmos and open collector Brown Out circuit chips to be fitted if the user chooses to use one, as the 40 pin footprints match older PICmicro devices also.
Provision for LCD 14/16 pin header, and mounting holes for selected 1 and 2 line displays, plus contrast pot.
Provision for Crystal (and Caps), or Resonator Oscillator.
A 40 pin header (40 pin dip compatible) at the top edge of the board.
DS-1302 Real Time Clock.
SimmStick compatible, which means it is a Load/Run operation for Flash Micros if used in conjunction with a suitable programming platform such as the DT001.
10 pin programming header that matches the programming header on the DT001 board.


Assembly Instructions:

Also read DT001 for programming a Flash PICmicro SimmStick in slot 1
Read P16PRO regarding software Registration for programming the 87x family.

The Micro can be any of the new flash 87x family and many old PICmicros that fit the 28 pin skinny Dip and 40 pin DIP footprints.

You can even change Micro types if you install a 28 pin socket in the U5 position, and two 20 pin machine pin strips into the U1 position.

1 by 780L5 +5 VR1 Voltage regulator in TO-92 case. (Optional)

1 by Capacitor C5 15pf Ceramic (This should suit all types of Crystals)
1 by Capacitor C6 15pf Ceramic (Read page 135 of the data sheet for full details.)
And either a Crystal of a suitable value, or a 3 pin Resonator. If a crystal is fitted then C5 and C6 must be installed. If you use a Resonator, then you mustn't install these two caps.

1 by Capacitor C9  10uf Tantalum or Electro.
1 by Capacitor C10 .01uf (or .1uf) Ceramic
1 by Capacitor C11 .01uf (or .1uf) Ceramic
1 by Capacitor C12 10uf Tantalum or Electro.
1 by Capacitor C13 .01uf (or .1uf) Ceramic
1 by Capacitor C14 .01uf (or .1uf) Ceramic

1 by Resistor  R1 10K .25 watt
1 by Resistor  R2 10K .25 watt
1 by Resistor  R3 470 Ohms .25 watt
There is an option for a series resistor between OSC2 and the crystal.  The 16F87x data sheet shows this resistor in Figure 12-2 on page 135 of the data sheet. Use a 470 ohm resistor there when running the chip in HS mode, or it will burn up the crystal very quickly.

1 by Resistor  R4 10K .25 watt
1 by Resistor  R5 10K .25 watt
1 by Resistor  R6 10K .25 watt

X1 Crystal or Resonator to match your clock requirements.
The most common device used is a 20Mhz Crystal and two 15pf caps.

X2 32.768khz Crystal and C7 and C8 (22pf Ceramic)
Optional Timer 1 input.

X3 32.768khz Crystal with a load capacitance of 6pf. (For Optional DS-1302 Clock)

POT 1 10K (For Optional LCD)

Optional RS-232 Serial Communications:
1 by Capacitor C1 1uf Electrolytic (PCB mount.) or Tant. @16 V.
1 by Capacitor C2 1uf Electrolytic (PCB mount.) or Tant. @16 V.
1 by Capacitor C3 1uf Electrolytic (PCB mount.) or Tant. @16 V.
1 by Capacitor C4 1uf Electrolytic (PCB mount.) or Tant. @16 V.
1 by MAX-232 U2 (or equivalent)
It may also pay to install a 16 pin socket for the Max-232, 
as you may have to remove it for some configurations.      


Optional RS-485 Serial Communications:
1 by MAX-485 U5 (or equivalent)

RS-232 and RS-485 Comms can't be installed together as the chip footprints overlap each other.

Brown-Out Circuit:
This small IC (U6) in a TO-92 package is used to stop the Micro operation becoming unpredictable during a power 'brown-out'. In most cases this isn't required. It's just an added precaution for reliable operation. The older PICmicros may well need this device. You don't need it for an 87x chip.

By just simply ignoring the brown-out circuit and installing resistors R1 and R2, the circuit operation should be fine.
R1, R2, and R3 must be installed at all times for normal operation. Yes, even if you don't use a brown-out circuit.

If you wish to use the brown-out circuit, it's just added to the board, and can be either a CMOS or Open Collector type.
You can use the following I.C.'s:
Panasonic MN13811-S (Open Collector)
Panasonic MN1381-S (CMOS)
Zetek ZM33064
Motorola MC33064/P
Other types may also be suitable. These should switch at between 4.2 and 4.6Volts. This is for +5 Volt operation.


Serial Out Jumper block, default connected.

Serial In Jumper block, default connected.

Header block for unused gates of MAX-232

VCC Isolate to 40 pin header J1. Default Isolated.

Used to Isolate the +5V signal on the edge connector from the 78L05 regulator output if it is installed. Both outputs should never be used together. The track on the solder side of the board under JP5 needs to be cut to isolate the 78L05 regulator output. A test link and two male posts are used to reinstall the regulator output.

40 pin header, pin for pin layout compatible with 40 pin Micro.
Also read the notes on the J4 Programming header.

J2: Real Time Clock:
Used for Dallas DS-1302 to get power from a standby battery to it's VCC2.
The Dallas DS-1302  (U8) requires a crystal (X3) with a load capacitance of 6pf. We have these 32.768khz crystals in stock.
Sample code can be found at

The Real Time Clock control lines can be connected to here. Make sure you don't conflict with other signals used.

Programming header. Default connected through J4 on the solder side of the board.
This header mates with J1, the 10 pin programming Header on the DT001 board, and if a 10 pin header cable is made up with flat ribbon cable, the board can be programmed via this cable. You have to cut the tracks on the solder side of the DT106 board, but make sure you don't cut the earth track (pins 9 and 10) The other 4 tracks can be cut.
This allows the program/run switch on the DT001 board to be used. To return the header to a stand alone controller, 4 Test Links need to be used when the IDC crimp connector cable is removed. These must be placed across header J4, pins 1 and 2, 3 and 4, 5 and 6, and 7 and 8.
This header pinout is the same as the Dr. Russ Reiss Configuration, however a suitable cable can be made up to match it with any ISP programmer.

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Last modified: February 24, 2024