Application Description

• Question 1
  How to match the oscillating frequencies of the 3¹² encoders and decoders?
• Question 2
  How to use the three-state Address pins of the 3¹² series?
• Question 3
  How to use the Holtek MCU to implement the remote decoder function?

Question 1

How to match the oscillating frequencies of the 3¹² encoders and decoders?

Answer

3¹² series : 

For 3¹² series, the oscillating realations between encoders and decoders are : 
f_OSC (HT6030/HT6032/HT6034 decoder) = 33 f_OSC (HT6010/HT6012/HT6014)

If the HT6010 is used as encoder, a typical 3kHz oscillating frequency is recommended. The decoder device can be either HT6030, HT6032 or HT6034 whose decoder oscillating frequency is typically 33 times that of encoders, namely 99kHz. In the Oscillator Frequency/Supply Voltage graph in the HT6010/HT6012/HT6014 datasheet, take 5V application for example and the typical 3kHz oscillating frequency, a 1.0Mohm resistor is therefore selected. In the Oscillator Frequency/Supply Voltage graph in the HT6030/HT6032/HT6034 datasheet, take 5V and the 99kHz and the resistor will be around 91Kohm. Note that user can choose other resistor values as long as the frequency relation is kept and the decoder frequency is under 300kHz, otherwise it might result in decoding failure.

Question 2

How to use the three-state Address pins of the 3¹² series?

Answer

For the 3¹² series, the Address pins are CMOS Transmission Gates internally. The Address pins can be connected to VDD, VSS or left open. If the Address pin is connected to VDD, Dout will have data 1 waveform; If the Address pin is connected to VSS, Dout will have data 0 waveform; If the Address pin is left open, Dout will have 3^rd state data waveform.

Question 3

How to use the Holtek MCU to implement the remote decoder function?

Answer

Please refer to the relevant example code in "Application Notes" under the "Technical Support" section of our company web site.