74hc595arduinopwmshift-register
I need to expand Arduino Uno output.
After some search I have identified 74HC595 to extend my Digital output and TLC5940 for analog output.
I'have also found how to connect them separately to Arduino Uno:
This two setups share some pins, I've seen in this thread that other people use them together but I'm not sure how to connect them to my Arduino. Can you give me a hint?
Libraries are also compatible?
If you were running the LEDs in series then yes, you would need a higher voltage. You aren't though - otherwise they'd all be on or all be off. You are running them in parallel.
From what I understand of your description you have the one output of the '595 going into the anode of the all the LEDs of one column. The cathodes of these LEDs then go into separate inputs of the TLC for PWM.
And, as you say, the '595 can supply 35mA of current per output. That is enough for to light one LED reliably.
You will need to supply 6 times that current for 6 LEDs.
The simplest way would be to use a single transistor and resistor per column. For example, the '595 output connects to the base of an PNP transistor through a 1KΩ (for example) resistor. The emitter connects to Vcc, and the collector connects to the LEDs in the same way the output of the '595 used to. When the '595 sets an output low it turns on the transistor which then allows the current to flow from Vcc to the LEDs.
You can't use the TLC with, for example. a ULN2803 as they are both current sinks. You need something which can be a current source, which a transistor can be.
Your real question is how to control a 12V 4A motor from a 0-5V logic output such as from a arduino.
Probably the simplest way is to use a relay. Use a relay with a 5V coil and a low side NPN to drive it:
This can support relays that take up to 100mA or so to drive, which should be more than enough for relay run from 5V that can switch what you want. The other side of the relay is just like a ordinary switch. You put it in series with the 12V supply and the motor.
There are fancier ways to drive the motor, but this is simple, robust, and meets all the specs you provided.
You now say you want to control a 12V 500mA solenoid in stead of a 12V 4A motor. That is just like driving a relay, except in this case the current is higher and it will be powered from the 12V supply instead of the 5V supply. For the different supply the only change is to connect the high side of the coil and diode to the new supply.
The higher current procludes the relay drive circuit shown above. If bipolar transistors are used, more current gain is required than you can reasonably expect from a single part. This can be dealt with by using two transistors. I would just use a single logic level FET:
However, there are lots of ways to implement a low side switch for 12V and 500mA that is driven from a logic output.
Best Answer
You can use them together. Both chips can be controlled by the SPI protocol.
To answer your question you first need to understand SPI:
SPI utilizes 4 data wires. They are usually called MISO, MOSI, SCLK and CS (chip select) in Arduino world. MOSI stands for master out - slave in. MISO is then master in - slave out.
You need to connect your devices like this:
If you want to connect more TLC5940 chips at once, wire all the connections as in the previous table, but connect SOUT (17) of the first chip to the SIN (26) of the next one. You will then shift twice as many bits and the bits for the furthest device will have to go first.
If you need more 595s, connect Q7S pin (9) to the DS (14) of the next chip in the same way.
The following then applies to both of the chips, but the polarities might be different for some other devices.
When you change the polarity of SCLK from low (L) to high (H) logic level, both devices sample the data input and shift it in the internal register.
So you shift in the necessary number of bits by changing the MOSI value and cycling the SCLK pin.
Once you have all data in you change the polarity of the relevant CS from L to H to apply the internal register to the outputs. If you followed my table you have pin 8 working as CS for the 595 and pin 9 for the TLC5940.
Libraries should work unless they use configuration that is not compatible internally (timers, SPI setup..). You only need to make sure you configure the chip select pins correctly.
The details can be found in datasheets: