Building the Clock Tiles

This guide is for all three Clock Tiles: Clock Generator, Clock Divider, and Clock Multiplier. They all use the same PCB with the same component values. The differences are in the pull-up / pull-down resistor and jumper placement, and the software running on the microcontroller.

The two sets of jumpers are used to configure whether the central 3.5mm socket is connected to the pot giving CV control of the pot function, or if it goes to a separate CV or gate/trigger input. Both sets of jumpers should be in the same position: either joining the top two pins (labelled “SEP. POT” on the PCB), or joining the bottom two pins. The Clock Multiplier uses no jumpers, and has the top two pins hard-wired. More on this later…

Although the PCB has a footprint for an SMD microcontroller, the DIP (on a socket) is much easier to program and reprogram. If using the SMD microcontroller programming can be done through the DIP socket, even on a fully populated PCB. The latest revision has a tact switch instead of the SMD microcontroller pads. The tact switch makes it easier to change operating modes from the front panel.

Be sure to get the MCP1702 and not the MCP1700 power regulator — the 1700 can only handle up to 6V input.


BOM:

Qty
Value
Device
Package
Description
4 1k Resistor R0805 RESISTOR
1 2k Resistor R0805 RESISTOR
2 10k Resistor R0805 RESISTOR
3 100k Resistor R0805 RESISTOR
1 B10k Potentiometer 9MM SNAP-IN 9mm vertical snap-in pot, Alpha / Panasonic style with 6mm built-in knob.
1 100n Capacitor C0805 Non-Polarized capacitor
2 1u CAPACITOR_NPOL-0805 C0805 Non-Polarized capacitor
1 LED 3MM LED
1 1N4007 DIODE-DO214AC DO214AC Power protection DIODE
4 B54S BAT54S Schottky Diodes BAT54S_SOT23 Schottky barrier (double) diodes
1 MCP1702-5 TO92-INLINE LDO Regulator
1 Tact Switch 6×6 13mm Tact Switch 6*6mm 13mm Through Hole SPST-NO https://www.taydaelectronics.com/tact-switch-6-6mm-13mm-through-hole-spst-no.html
1 TILE-POWER Cable FUTABA-SMALL http://pulplogic.com/product/tile-tail/
1 ATTINY85-20 DIP08 Atmel 8-pin 2/4/8kB flash uC
1 Header 1X01 Male PIN HEADER
2 Header 1X03 Male PIN HEADER
3 3.5mm Jack THONKICONN 3.5mm socket for Eurorack modular synths https://www.thonk.co.uk/shop/3-5mm-jacks/
1 DIP Socket 8-pin
2 Jumpers 2.54mm

Schematics:


Build Instructions

Clean PCB with isopropyl alcohol to remove any manufacturing residues.

Now is also a good time to file away the “mouse bites” that separate the PCB and Panel.

Solder the surface mount devices. Each of the three modules uses different configurations of input and output pull-up and pulld-own resistors. Leave the unused spots empty.

If building the Clock Multiplier, the wire jumpers can be soldered in now. Bend a bit of discarded resistor lead into a U and drop it into the holes to connect those traces. Trim the leads flush on the other side so it won’t interfere with the socket later.

 


map_7168_lznAdd the SMD-side through-hole components (microcontroller socket and MCP1702-5 power regulator. The Clock Divider and Clock Generator can have their jumper pins installed now.

map_7177_lzn

 

 

Trim the IC Socket pins almost flush to the bottom of the PCB so they won’t interfere with the potentiometer (they shouldn’t anyway).

 


map_7183_lznmap_7184_lzn

Straighten the potentiometer “snap in” supports so that they can clear the DIP socket when being installed.

 

They may need to be flared outwards a wee tad.

Before soldering the pot double-check to make sure the DIP pins are contacting the metal body.

 


map_7188_lznUse the panel to help align the sockets, tact switch (not shown in photo) and LED. Solder into place.

The power cable can be installed now.


TESTING

map_7204_lznCheck for shorts between the contacts on the power cable, and between Pin 4 and Pin 8 of the IC Socket. If there is a short, it most likely is a solder jumper between the legs of the BAT54S.

Assuming no shorts, apply power and check that Pin 8 has 5V and none of the other pins have 12V.

If testing the Clock Divider or Clock Generator, add jumpers to the two sets of jumper pins. They should both go over the same set of pins: 1 and 2, or 2 and 3. Don’t put on jumper on 1-2 and the other on 2-3. The module won’t function properly without jumpers.

Add the appropriate programmed microcontroller, and power-up the module. The led should immediately flash to signal that it has booted and loaded any EEPROM presets without error.

Test all inputs and outputs with the jumpers (if jumpered) in both positions.


CODE

Bootloader: Attiny85 16MHz internal clock

Clock Multiplier 2018

Clock Generator 2018

Clock Divider 2018

Older source for PCBs without tact switch:

http://bitbucket.org/thx2112/clock-multiplier-tile/src

http://bitbucket.org/thx2112/clock-generator-tile/src

http://bitbucket.org/thx2112/cv-clock-divider-tile/src