UPD70F3786GJ-GAE-AX Renesas Electronics America, UPD70F3786GJ-GAE-AX Datasheet - Page 1527

• Manufacturer Part Number: UPD70F3786GJ-GAE-AX
• Description: MCU 32BIT V850ES/JX3-E 144-LQFP
• Manufacturer: Renesas Electronics America
• Series: V850ES/Jx3-Er

Specifications of UPD70F3786GJ-GAE-AX

• Core Processor: RISC
• Core Size: 32-Bit
• Speed: 50MHz
• Connectivity: CAN, CSI, EBI/EMI, Ethernet, I²C, UART/USART, USB
• Peripherals: DMA, LVD, PWM, WDT
• Number Of I /o: 100
• Program Memory Size: 512KB (512K x 8)
• Program Memory Type: FLASH
• Ram Size: 124K x 8
• Voltage - Supply (vcc/vdd): 2.85 V ~ 3.6 V
• Data Converters: A/D 12x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

23.7 Receive Checksum
sufficient area must be allocated.
bytes) and CRC (last 4 bytes), are subject to checksum calculation. If the number of bytes subject to calculation is
odd, 00H is added to the last byte.
packet length is 18 bytes (payload = 0 byte) or less, 0 is output as the checksum.
23.7.1 Processing by software
Therefore, calculation starts from the 15th byte. If the MAC header exceeds 14 bytes, such as in a VLAN and huge
frame, correction by software is necessary.
The Ethernet controller has a receive checksum unit that can a receive checksum.
Receive checksum calculation is enabled and disabled by setting the RXCHKSMEN bit of register.
A checksum is appended to the end of receive data. Because receive data has size of packet length + 2 bytes, a
While checksum calculation is enabled, all parts (payload) of a receive frame, except the MAC header (first 14
The minimum receive packet length subject to checksum calculation is 19 bytes (payload = 1 byte). If the receive
However, the length information increases by 2 bytes.
Before changing the value of the RXCHKSMEN bit, confirm that transfer of the receive frame has stopped.
The first 14 bytes of a packet are treated as a MAC header and are always excluded from checksum calculation.
Checksum of only IP header must
be calculated by software.
Note The first 14 bytes are always excluded from the checksum calculation.
Checksum
A dummy header checksum must
be appended to the checksum
calculated by Ethernet controller
by software.
MAC header
14 bytes
CHAPTER 23 ETHERNET CONTROLLER
Figure 23-30. Checksum Calculation
Checksum
Checksum
Note
,
User’s Manual U19601EJ2V0UD
Dummy header
checksum
4 bytes
CRC
PAYLOAD
+
IP header
TCP header
Checksum
2 bytes
Hardware
(Checksum calculated by Ethernet
Areas subject to calculation
All areas except MAC header and
CRC
controller)
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