FiveCo FMod-TCP BOX User Manual page 16

To be able to do all of these 3 sequences, use this command:
Byte#
0x00 I2CRWwithAck (0x0007)
0x02 TransactionID
0x04 LengthOfParameters (X + 3)
0x06 7 bits Address (bit 7 = 0)
0x07 X (number of bytes to write) 8 bits
0x08 xBytes
.... Y (number of bytes to read)
The four previous entries can be replicated to access the same or other I2C slaves within this
command sequence.
Checksum
If X = 0, the Read method is used.
If Y = 0, the Write method is used.
If X & Y ≠ 0, the Read after Write method is used.
The answer sequence is the following one:
Byte#
0x00 I2CReadAnswer (0x0008)
0x02 TransactionID (same as
demand)
0x04 Number of bytes in answer
0x06 Answer bytes
... Ack state of the I2C com.
If the same or other I2C slave have been accessed in the command, the answer bytes and ack
state is added here.
... Checksum
The "Ack state" byte is composed of the following bits:
0 Address ack in write sequence
1 Bytes written ack (each byte was acked)
2 Address ack in read sequence
3-6 Reserved
7 Must be always 1
The user can use these bits to check for the presence of his I2C devices and
monitor hardware issues.
Number of bits
16 bits
16 bits
16 bits
8 bits
X bytes
8 bits
16 bits
Number of bits Example
16 bits 0x0008
16 bits 0x1254
16 bits 0x0005
Y bytes 0x1A25...
1 byte 0x87
16 bits 0x...
0 = No answer to this address
1 = ack received
0 = Bytes not acknowledged
1 = ack received
0 = No answer to this address
1 = ack received
-
1
FMod-TCP User Manual v.2.8
16 / 58
Example
0x0007
0x1B34
0x0005
0x28
0x02
0xAF1D
0x05
0x...