R8C/3MK Group
USB-to-Serial Communication Conversion Demo Board
R0K5R8C3MDU30BR Instruction Manual
R01AN1051EJ0100 Rev.1.00
Page 32 of 38
Mar 21, 2012
When you indicate address and write data to the SSU device, you send the “Write Access” command
packet to the virtual COM port, and send data packet continuously. Figure 36 shows the protocol
conversion of Write Access. If the data packet length is short (less than 59bytes), you can combined
command packet and data packet to “combined packet”.
USB Packet
Control
0x20
Dummy
0x00
Instruction
0x02
Len(Lower)
0x02
Len(Upper)
0x00
Data(D001)
0x01
SSU Packet
Instruction
0x02
Data(D001)
0x01
Protocol Conversion of Memory Write(Send 2 Bytes Data)
First Packet:
Send Command Packet
Second Packet:
Send Data Packet (2bytes)
First Packet:
Send Command and Data
Data(D002)
0x40
Data(D002)
0x40
SSU Transmission
SSU Reception
Address(Lower)
0x00
Address(Upper)
0x00
Address(Lower)
0x00
Address(Upper)
0x00
A
C
K
A
C
K
O
U
T
O
U
T
Figure 36 Protocol Conversion of Memory Write
10.2.5
Protocol Conversion of Instruction Write
When you write 1 byte data (Instruction) to the SSU device, you send the “Instruction Write” command
packet to the virtual COM port. Figure 37 shows the protocol conversion of Instruction Write
USB Packet
Control
0x30
Dummy
0x00
Instruction
0x??
Len(Lower)
0x00
Len(Upper)
0x00
SSU Packet
Instruction
0x??
Protocol Conversion of Instruction Write
First Packet:
Send Command Packet
Send Command (1byte)
SSU Tranmission
O
U
T
A
C
K
Figure 37 Protocol Conversion of Instruction Write
