Chengdu Ebyte Electronic Technology Co., Ltd.
E810-TTL-CAN01 User Manual
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Chengdu Ebyte Electronic Technology Co., Ltd.
17
4.9 ModBus mode
Modbus conversion mode supports RTU conversion mode. The E810-TTL-CAN01 module is used as a slave
device to receive and respond to commands sent by the host (via the UART).
The E810-TTL-CAN01 conversion module supports two Modbus commands: read register (function code 03)
and write multiple registers (function code 16).
A buffer is internally built in the conversion module for buffering the received CAN frame data, and the buffer
has a total of 64 levels of buffer according to the addresses 0~63. The cache address starts from 0 to address 63, and
can continuously buffer 8 frames of CAN data (8 bytes per frame, a total of 64 bytes). When the first frame of CAN
data is received, the CAN frame data is stored in address 0, and the received CAN frame data is sequentially stored in
increasing order according to the address. If the 64-level cache is full, the newly received CAN frame data will be
stored in address 0 and overwrite the original number, following FIFO.
Read register (function code 03):
Send command:
[Device Address] [Command No. 03 (0x03)] [Start Register Address is 8 Bits High] [8 Bits Low] [Read Register
Numbers is 8 Bits High] [8 Bits Low]
[High 8 bits of CRC check] [Lower 8 bits of CRC check]
