Data Sheet

iolinker Family Data Sheet

4.4 Command Destination Address

The target address byte of the format 0sss ssss allows to target speciﬁc slave devices with

a command. Each device processes messages only when addressed correctly with its user-

deﬁned slave address. The slave address can be conﬁgured through the hardware address

pins as described in section 9.1.2.

The target address 0x7f holds a special function in the protocol, for it is always

executed, regardless of the actual slave address. This allows to target all chips on the

bus simultaneously.

Warning: Avoid using the universal slave address for read commands entirely

when connecting multiple slaves. If multiple slaves were to reply to a read command

simultaneously, they would cause a bus conﬂict and possible short circuit.

4.5 Command Encoding

The command byte is of the format 1W00 cccc.

W Indicates if the operation is a Read (1) or a Write (0)

cccc 4 bit command number

Table 2: Command byte parameter description

The ﬁrst nibble of the command byte therefore has the following possible values:

Hex Binary Function

0x8 0b1000 Write command

0xC 0b1100 Read command

Table 3: Command byte, ﬁrst nibble

4.6 Command Buﬀer

Commands that change output pin states can be buﬀered. Buﬀered commands are not

executed until a TRG message is received. Command buﬀering begins by issuing a SYN

command.

4.7 Command List

4.7.1 VER – Retrieve chip version

Function Return version and slave address

Command byte 0xC1

Argument list –

Reply argument list Version byte, GPIO count byte

Example reply arguments 0x01 0x31 (Version 1, 49 GPIOs)

 2017 jInvent. The speciﬁcations and information herein are subject to change without notice.