UCD3138: UCD3138RJAR UV setting via PMBus

Hello Colin,

Do you want to change the UV in the Fusion GUI or the PMBus code? Changing the UV threshold in the Fusion GUI is fairly straightforward.

If you want to change how the UV handling is done in the UCD3138, then you can go to pmbus_topology.c to see how the UCD3138 will respond to a UV command. For example, if the Fusion GUI or some PMBus controller sends the 0x44 pmbus command (defined as VOUT_UV_FAULT_LIMIT per the PMBus spec), then the UCD3138 will execute the pmbus_read_write_vout_uv_fault_limit() function. If you want to change what the UCD3138 will do in response to this command, then you can do so here.

Below is a snippet of the code related to the UV Fault in the UCD3138 LLC code, as an example. The below is located in pmbus_topology.c. 

//UV Fault
inline Uint8 pmbus_write_vout_uv_fault_limit(void)
{
	pmbus_dcdc_config[0].vout_uv_fault_limit = pmbus_buffer[1] + (pmbus_buffer[2] << 8);
	configure_fault_levels();
	return PMBUS_SUCCESS;
}
inline Uint8 pmbus_read_vout_uv_fault_limit(void)
{
	pmbus_read_two_byte_handler(pmbus_dcdc_config[0].vout_uv_fault_limit);
	return PMBUS_SUCCESS;
}

Uint8 pmbus_read_write_vout_uv_fault_limit(Uint8 pmbus_read)
{
	if(pmbus_read)
		return pmbus_read_vout_uv_fault_limit();
	else
		return pmbus_write_vout_uv_fault_limit();
}

//UV fault response


inline pmbus_read_vout_uv_fault_response(void)
{
	  pmbus_read_one_byte_handler(pmbus_dcdc_config[0].vout_uv_fault_response);
	  return PMBUS_SUCCESS;
}

inline pmbus_write_vout_uv_fault_response(void)
{
	pmbus_dcdc_config[0].vout_uv_warn_limit= pmbus_buffer[1];
	return PMBUS_SUCCESS;
}

Uint8 pmbus_read_write_vout_uv_fault_response(Uint8 pmbus_read)
{

	if(pmbus_read)
			return pmbus_read_vout_uv_fault_response();
		else
			return pmbus_write_vout_uv_fault_response();
}

//UV Warn
inline Uint8 pmbus_write_vout_uv_warn_limit(void)
{
	pmbus_dcdc_config[0].vout_uv_warn_limit = pmbus_buffer[1] + (pmbus_buffer[2] << 8);
	configure_warning_levels();
	return PMBUS_SUCCESS;
}
inline Uint8 pmbus_read_vout_uv_warn_limit(void)
{
	pmbus_read_two_byte_handler(pmbus_dcdc_config[0].vout_uv_warn_limit);
	return PMBUS_SUCCESS;
}

Uint8 pmbus_read_write_vout_uv_warn_limit(Uint8 pmbus_read)
{
	if(pmbus_read)
		return pmbus_read_vout_uv_warn_limit();
	else
		return pmbus_write_vout_uv_warn_limit();
}

Regards,

Jonathan Wong