
Touch Switch Detection Tool Demo Board Introduction
4
Circuit Description
•P1 is the input 9V DC power source and which after filtering by C6 and C2 is provided
to the 7805 regulator pin 1. The pin 3 output of the regulator provides the 5V supply for
the MCU. The MCU power can also be directly provided on V1 and V2. Another way is
to provide the power via PIN1 and PIN5 on H2. Any one of the three methods of
supplying power can be chosen.
•C1, C3, C4, R1 and R2 form the MCU reset circuit.
•D1 is the four digit display which is used to display the data received on the serial port.
DS0~DS3 are LEDS which are used to display the corresponding RC channel in HEX
format.
•S1, S2 and S3 are the ADD, DEC and MODE switches and are used to setup the
channel and operating modes.
•H2 is the serial communication interface. This application uses the CS, CLK and DATA
three line communication method. Among these PC0 corresponds to CS, PC1
corresponds to CLK and PC2 corresponds to DATA. The data is read on the falling
edge of the CLK signal.
Note: when the MCU power supply is provided on P1 as a 9V DC supply, or by using the
V1 and V2 direct MCU supply, PIN1 on H2 does not have to be connected.
Communication Protocol Description
Serial Communication Protocol Description
This application uses a three wire protocol for communication. The HT48R10A-1 is a
SLAVE terminal whose communication method is as follows:
•The data total length is 24-bits among which the display data is 16-bits and the display
channel is 8-bits.
•Data transmission is to first transmit the 16-bit data for display, then transmit the 8-bit
channel display information. The transmission method is LSB first.
•When displaying the 8-bit channel, only the lowest four bits are used, the highest four
bits are required to be the same as the lower four bits and are used to determine if the
display data has been received correctly.
•The data must be ready on the falling edge of the CLK signal.