E6248 Atmel, E6248 Datasheet - Page 26

• Manufacturer Part Number: E6248
• Description: BOARD EVAL QT60248-AS QMATRIX
• Manufacturer: Atmel
• Series: Quantum, QMatrix™r

Specifications of E6248

• Sensor Type: Touch, Capacitive
• Sensing Range: 16 / 24 Buttons/Keys
• Interface: SPI Serial
• Voltage - Supply: 3 V ~ 5 V
• Embedded: No
• Utilized Ic / Part: QT60168, QT60248
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Sensitivity: -
• Other names: 427-1087

7 Appendix
7.1 8-Bit CRC Algorithm
// 8 bits crc calculation. Initial value is 0.
// polynomial = X
// data is an 8 bit number;
unsigned char eight_bit_crc(unsigned char crc, unsigned char data)
{ unsigned char index;
}
A CRC calculator for Windows is available free of charge from Quantum Research.
lQ
unsigned char fb;
index = 8;
do
{ fb = (crc ^ data) & 0x01;
} while(--index);
data >>= 1;
crc >>= 1;
If(fb)
{ crc ^= 0x8c;
}
return crc;
8
+ X
5
// initialise the shift counter
+ X
4
+ 1
crc is a 8 bit number
// shift counter
26
QT60248-AS R4.02/0405