FFI for clamp control

[campagnola]

Currently I am accessing GUI elements directly for many these. My ideal API would look like:

GetClampState(headstage)
   Returns: 
   {
       'Mode': 'IC'|'VC'|'I=0',
       'HoldingPotential': float, 
       'HoldingPotentialEnable': bool,
       'BiasCurrent': float, 
       'BiasCurrentEnable': bool,
        'AutoBiasVcom': float,
        'AutoBiasVcomVariance': float,
        'AutoBiasIbiasmax': float,
        'AutoBiasEnable': float,
        'PipetteOffsetVC': float,
        'PipetteOffsetIC': float,
   }

SetClampMode(headstage, mode)
SetHoldingPotential(headstage, value, enable) 
SetBiasCurrent(headstage, value, enable) 
SetAutoBias(headstage, target_potential, enable)
SetHeadstageActive(headstage, enable)
SetTestPulseEnable(headstage, enable)
AutoPipetteOffset(headstage)
AutoCapacitance(headstage)
AutoBridgeBalance(headstage)

Notes:

• All of the functions above are currently possible by accessing GUI elements directly, but many require multiple requests that degrade performance (including setting the headstage selection slider)
• If GetClampState is too expensive as written, it could be broken up into more targeted requests
• All of the values returned by GetClampState are currently being read using the pub/sub topic 'amplifier:set value', but it is also necessary to be able to explicitly request these before such message has been received
• All Set..() functions should return only after the change is complete
• You're welcome to simplify the API by combining set functions, like setClampParameter(headstage, param_name, value)
• Maybe you'll want to add device as the first argument to all functions?

[MichaelHuth]

• [x] GetClampState(headstage) -> FFI_GetClampState(string device, variable headstage)

• [x] SetClampMode(headstage, mode) -> FFI_SetClampMode(string device, variable headstage, variable clampMode)

• [x] SetHoldingPotential(headstage, value, enable) -> FFI_SetHoldingPotential(string device, variable headstage, variable potential)

• [x] SetBiasCurrent(headstage, value, enable) -> FFI_SetBiasCurrent(string device, variable headstage, variable biasCurrent)

• [x] SetAutoBias(headstage, target_potential, enable) -> FFI_SetAutoBias(string device, variable headstage, variable potential, variable enable)

• [x] SetHeadstageActive(headstage, enable) -> FFI_SetHeadstageActive(string device, variable headstage, variable enable)

• [x] SetTestPulseEnable(headstage, enable) -> FFI_SetTestPulseEnable(string device, variable headstage, variable enable)

• [x] AutoPipetteOffset(headstage)

• [x] AutoCapacitance(headstage)

• [x] AutoBridgeBalance(headstage) -> FFI_TriggerAutoClampControl(string device, variable headstage, variable autoCtrl)

[MichaelHuth]

AI_GetFunctionConstantForClampMode -> get ctrl names -> AI_AmpStorageControlToRowLabel and then read from GetAmplifierParamStorageWave

AI_MapFunctionConstantToName for clampState wave

Adapt amplifier function such that GUIWrite = 1 only is effective if current HS equals requested headstage -> done in AI_UpdateAmpView

Move range checks to lower AI_ functions

ctrl = GetPanelControl(i, CHANNEL_TYPE_HEADSTAGE, CHANNEL_CONTROL_CHECK)