C8051F819-GM Silicon Laboratories Inc, C8051F819-GM Datasheet - Page 160

• Manufacturer Part Number: C8051F819-GM
• Description: IC MCU 8BIT 8KB FLASH 20QFN
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F81xr

Specifications of C8051F819-GM

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: SMBus (2-Wire/I²C), SPI, UART/USART
• Peripherals: Cap Sense, POR, PWM, WDT
• Number Of I /o: 17
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 3.6 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-QFN
• Processor Series: C8051F8x
• Core: 8051
• Data Bus Width: 16 bit
• Data Ram Size: 512 B
• Interface Type: I2C, SPI, UART
• Maximum Clock Frequency: 25 MHz
• Number Of Programmable I/os: 17
• Number Of Timers: 3
• Operating Supply Voltage: 1.8 V to 3.6 V
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: PK51, CA51, A51, ULINK2
• Development Tools By Supplier: C8051F800DK
• Minimum Operating Temperature: - 55 C
• Package: 20QFN EP
• Device Core: 8051
• Family Name: C8051F8xx
• Maximum Speed: 25 MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Data Converters: -
• Lead Free Status / Rohs Status: Details
• Other names: 336-1799-5

C8051F80x-83x
24.1. 16-bit CRC Algorithm
The C8051F80x-83x CRC unit calculates the 16-bit CRC MSB-first, using a poly of 0x1021. The following
describes the 16-bit CRC algorithm performed by the hardware:
1. XOR the most-significant byte of the current CRC result with the input byte. If this is the first iteration of
2. If the MSB of the CRC result is set, left-shift the CRC result, and then XOR the CRC result with the
3. If the MSB of the CRC result is not set, left-shift the CRC result.
4. Repeat at Step 2 for the number of input bits (8).
For example, the 16-bit C8051F80x-83x CRC algorithm can be described by the following code:
unsigned short UpdateCRC (unsigned short CRC_acc, unsigned char CRC_input){
}
Table 24.1 lists example input values and the associated outputs using the 16-bit C8051F80x-83x CRC
algorithm (an initial value of 0xFFFF is used):
160
the CRC unit, the current CRC result will be the set initial value (0x0000 or 0xFFFF).
polynomial (0x1021).
unsigned char i;
#define POLY 0x1021
// Create the CRC "dividend" for polynomial arithmetic (binary arithmetic
// with no carries)
CRC_acc = CRC_acc ^ (CRC_input << 8);
// "Divide" the poly into the dividend using CRC XOR subtraction
// CRC_acc holds the "remainder" of each divide
// Only complete this division for 8 bits since input is 1 byte
for (i = 0; i < 8; i++)
{
}
return CRC_acc; // Return the final remainder (CRC value)
// Check if the MSB is set (if MSB is 1, then the POLY can "divide"
// into the "dividend")
if ((CRC_acc & 0x8000) == 0x8000)
{
}
else
{
}
// if so, shift the CRC value, and XOR "subtract" the poly
CRC_acc = CRC_acc << 1;
CRC_acc ^= POLY;
// if not, just shift the CRC value
CRC_acc = CRC_acc << 1;
0x00, 0x00, 0xAA, 0xBB, 0xCC
0xAA, 0xBB, 0xCC
Table 24.1. Example 16-bit CRC Outputs
Input
0x63
// loop counter
Rev. 1.0
0xBD35
0x6CF6
0xB166
Output