[Etherlab-users] User mode "Register" access methods

[Richard Hacker]

The 'ecrt_reg_*' family of functions in the C-API mirror the 'reg_*'
functions of the CLI tool.

The ESC registers are reserved for the master. As an EtherCAT user, you
do not need to touch them.



On Wed, 2026-04-22 at 14:16 +0000, Moebius, Volker wrote:
> 
> 
> 
> Hello everyone,
>  
> The `ethercat` CLI tool implements the “Register Access” functions
> `reg_read` and `reg_write`. These functions are using
> EC_IOCTL_SLAVE_REG_READ and EC_IOCTL_SLAVE_REG_WRITE to execute these
> methods. (lines 433ff of tool/MasterDevice.cpp)
>  
> Is there a reason why possibly corresponding methods for “Register
> Read” and “Register Write” aren’t implemented in the “normal” user
> mode C API (include/ecrt.h)? Don’t these methods make sense for
> controlling EtherCAT slaves?
>  
> I’m unfortunately not an EtherCAT expert and I’m confused about the
> different data objects and communication objects. Are the functions
> `ecrt_slave_config_create_reg_request`, `ecrt_reg_request_data`,
> `ecrt_reg_request_state`, `ecrt_reg_request_write` and
> `ecrt_reg_request_read` related to the same “Register Access” (“Slave
> Registers”) as implemented by the CLI? Or do they manage a different
> kind of registers?
>  
> .

-- 
Mit freundlichem Gruß / Best regards,
Richard Hacker
--  
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