Question: how to use the write_single_coil() to write on the different positions?

[beyonlo]

Hello @brainelectronics

I'm using the #10 for tests.

How is possible to use the write_single_coil() to write in position 3, for example? In this example below the ouput_value is setting always to the first position:

>>> host.read_coils(slave_addr=10, starting_addr=123, coil_qty=1)
[False, True, True, False, False, False, False, False]
>>> host.write_single_coil(slave_addr=10, output_address=123, output_value=1)
False
>>> host.read_coils(slave_addr=10, starting_addr=123, coil_qty=1)
[True, False, False, False, False, False, False, False]
>>> 

Using this register_definitions:
{'ISTS': {'EXAMPLE_ISTS': {'register': 67, 'len': 1, 'val': 0}}, 'IREGS': {'EXAMPLE_IREG': {'register': 10, 'len': 2, 'val': 60001}}, 'HREGS': {'EXAMPLE_HREG': {'register': 93, 'len': 1, 'val': 19}}, 'COILS': {'EXAMPLE_COIL': {'register': 123, 'len': 3, 'val': [0, 1, 1]}}}

[beyonlo]

Very importat: I suppose that when use output_value without a list, I mean, just 1/0/True/False like as example above, it will be write on the first position, (position 0), is that right? That is a bit confuse. In my opinion is more clear always to use a list when need to write COILS. So even that you need to write just one COIL, in the first position, need to use always output_value=[1], What do you think? That will prevents confusion. So in this case the register definitions need always to use list as well: EXAMPLE_COIL': {'register': 123, 'len': 3, 'val': [0,1,1] or if has all 0/False, can use empty list: EXAMPLE_COIL': {'register': 123, 'len': 3, 'val': [ ] . Anyway, always is need to be documented: as each register is by definition 2 bytes (16 bits), so coils that are not defined, is by default 0/False. So EXAMPLE_COIL': {'register': 123, 'len': 3, 'val': [0,1,1] is the same thing that to do EXAMPLE_COIL': {'register': 123, 'len': 3, 'val': [0,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0]. Is that make sense for you?

Edit: maybe is a good idea to have a simple doc (with examples) about how to use.

[brainelectronics]

Relates to #26

[brainelectronics]

Relates to #35, same root cause for this issue. Access to the elements of a list of a register value is missing/not yet possible

Registers are defined as specified by the register element, see

micropython-modbus/umodbus/modbus.py

Lines 53 to 55 in c45d6cc

	self._set_reg_in_dict(reg_type='COILS',
	address=address,
	value=value)

for a coil. The provided value is added as value to the dictionary at the key register, here 93. Thereby no element/key 94 exists in the Modbus _register_dict