The product is made by 4 8×8 led matrices and an Holtek HT1632C controller:
In this first tutorial, I’m going to show how to communicate with control chip…
HT1632C chip implements a protocol similar to SPI; you can control the chip through 3 pins:
- CS (chip select)
- WR (write)
CS pin has to be low to enable the communication; you can connect up to 4 boards in a chain configuration. In the back of the board you can use a dip switch to configure the address of each display:
The connector has 4 chip select pins you can use to activate the particular display with that address:
DATA pin is used for serial communication, both input and output. The HT1632C chip has an internal pull-up resistor on this pin.
WR pin controls when a write occurs: DATA pin is read by HT1632C on a rising edge (from logic level 0 to logic level 1) of this pin.
If you need also to read data from the chip, you can use the RD pin that – like WR pin – controls when HT1632C writes the requested bits on DATA pin.
HT1632C has an internal RAM memory organized in 64×4 bits and an output pin corresponds to each memory cell. A logic level 1 in the cell corresponds to an high output (i.e. led on).
Using READ and WRITE commands you can change RAM content and as a consequence the state of output pins. Both the commands support single access to a cell memory and the ability to change, with a single operation, the whole content of the RAM.
In this first tutorial I gave a brief introduction of the display and the control chip; in the next ones I’m going to show how to control it using your Arduino… stay tuned!