M30845FJGP#U3 Renesas Electronics America, M30845FJGP#U3 Datasheet - Page 291

• Manufacturer Part Number: M30845FJGP#U3
• Description: IC M32C MCU FLASH 512K 144LQFP
• Manufacturer: Renesas Electronics America
• Series: M16C™ M32C/80r

Specifications of M30845FJGP#U3

• Core Processor: M32C/80
• Core Size: 16/32-Bit
• Speed: 32MHz
• Connectivity: CAN, I²C, IEBus, SIO, UART/USART
• Peripherals: DMA, PWM, WDT
• Number Of I /o: 121
• Program Memory Size: 512KB (512K x 8)
• Program Memory Type: FLASH
• Ram Size: 24K x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 5.5 V
• Data Converters: A/D 34x10b, D/A 2x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 144-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

M
R
R
20. CRC Calculation
e
E
3
. v
J
2
Figure 20.2 CRCD Register and CRCIN Register
Figure 20.1 CRC Calculation Block Diagram
0
C
The CRC (Cyclic Redundancy Check) calculation detects an error in data blocks. A generator polynomial
of CRC_CCITT (X
The CRC code is a 16-bit code generated for a block of data of desired length. This block of data is in 8-bit
units.The CRC code is set in the CRCD register every time one-byte data is transferred to the CRCIN
register after a default value is written to the CRCD register. CRC code generation for one-byte data is
completed in two cycles.
Figure 20.1 shows a block diagram of a CRC circuit. Figure 20.2 shows associated registers. Figure 20.3
shows an example of the CRC calculation.
1
9
0 .
8 /
B
0
1
4
0
3
G
J
6
u
o r
0 -
. l
CRC Input Register
b7
CRC Data Register
b15
u
0
1
p
, 7
0
1
(
2
M
0
3
0
5
2
C
b8 b7
16
8 /
Page 268
, 4
+ X
M
12
3
2
+ X
C
b0
b0
f o
8 /
5
4
4
After default value is written to the CRCD
register, the CRC code can be read from the
CRCD register by writing data to the CRCIN
register. Bit position of the default value is
inversed. The inversed value is read as the CRC
code.
+ 1) generates CRC code.
Data input.
Inverse bit position of data.
) T
9
5
Symbol
CRCIN
Symbol
CRCD
CRCIN register
High-order bits of data bus
Low-order bits of data bus
CRC code generation circuit
8 low-order bits
x
16
Function
Function
+ x
Address
037E
CRCD register
Address
037D
12
16
16
+ x
- 037C
5
+ 1
16
8 high-
order bits
After Reset
Indeterminate
After Reset
Indeterminate
0000
Setting Range
Setting Range
00
16
16
to FF
to FFFF
16
20. CRC Calculation
16
RW
RW
RW
RW