canled

CANLED

Note: The circuit diagram show R2 as 560 ohms, for normal brightness it's better to use 1k8.

CANLED is a consumer only module which accepts and learns events sent over the CBUS by other (producer) modules. It drives 64 separate LEDs using a 4 row by 16 column matrix. The column driver IC has a resistor to enable the LED current (brightness) to be adjusted. The column driver is a current sink so no external LED resistors are required.

Note: The current PCB has the yellow and green leds reversed, the yellow led should be in LD2.

The PCB layout is http://mergcbus.svn.sourceforge.net/viewvc/mergcbus/trunk/Documents/canled/CANLED_pcb.pdf

The circuit diagram is http://mergcbus.svn.sourceforge.net/viewvc/mergcbus/trunk/Documents/canled/CANLED_sch.pdf

Power supply

This module accepts its own AC supply of 9 to 15v (RMS) AC at 50 / 60 Hz. or it can be supplied directly with +5V through the CBUS connector. The AC is rectified by a bridge rectifier (BR1) and smoothed to DC by capacitor C1. Note that some other CBUS modules also require a similar AC supply and the same transformer can be used for all. There is a separate voltage regulator (U3) which supplies the rest of the circuit with a fixed 5v.

The maximum current available from this regulator is 1 amp. With all 64 LEDs illuminated and an average current of 10mA per LED, the module current is about 700mA. If an AC supply is used, the power dissipated in the 5V regulator is substantial. With a 15v RMS supply, the power is 10 watts and even with only 50% utilisation is 5 watts. A heatsink of not more than 100 C / watt is recommended. A preferable arrangement for this module is to supply the +5V directly from an external supply. The regulator may omitted completely in this case.

The green LED (LD2) will illuminate to show the circuit is working correctly. This is not just a power on indicator but confirms correct working of the processor.

Connecting the LEDs

The LEDs use a multiplexed array. This has 4 rows and 16 columns. The LED wiring connects to the D type socket on the PCB. Only 20 wires are required for all 64 LEDs. Refer to the schematic for the relationship between the row / column numbers and the socket connections. The average LED current is set by resistor R2. The suggested value gives an effective current of 10mA. If low current LEDs are used, then the average current may be reduced by increasing this resistor. This will also affect the brightness.

Additional Information

Original SLiM documentation: http://mergcbus.svn.sourceforge.net/viewvc/mergcbus/trunk/canled/slimasm/CANLED_a_txt.pdf

Changes for C version

Start-up led check. For the first time power-up all the leds come on until the setup button is pushed twice to get a canid and nodenumber. After that on power up all the leds come on for a short time. This does not use the normal display data area, so the real led state can update during the test.

In learn mode the led corresponding to the led select switch is on. This is useful for testing as well.

Node variable 0 dimming, 3 to 20, 3 (default) is brightest, 20 is dimest.

In SLiM systems the module should work as before after pressing the setup button twice to get the canid and node number. If there is a canid or nodenumber conflict then the module will stop until either the setup button is used to get a new canid and nodenumber or power is removed.

For FLiM mode teaching, subtract 1 from the led number, led numbers are 0 to 63. Events are stored as 5 bytes, the 4 byte event number and one byte event. The event byte is the 6 bits led number, 1 bit polarity, and 1 bit toggle. Add 64 for Invert Polarity, and add 128 for Toggle mode to the led number.