FlexCase E & G

Prerequisites

• Complete the quick start guide for a tutorial on connecting to the FlexCase and flashing binaries

Logic Active High/Low Info

See datasheet for pin/port information.

LSO:

• LSO_IN Input Signal (Set DO/PWM): This is an active high digital signal that can be set either HIGH or LOW.
• LSO_EN (Low Side Digital Output Enable): When set to HIGH, the switch is enabled, allowing the LSO1_IN signal to control the output effectively.
• LSO_STAT Pin (Read Feedback): This pin provides essential diagnostic feedback and automatic reset functionality. A HIGH LSO_STAT logic indicates normal operation, while a LOW logic signals an overtemperature condition.

HSO:

• HSO_IN (Set DO/PWM): This is an active high digital signal that can be driven either HIGH or LOW.
• DSEL Pin (High Side Digital Output Feedback): This pin can be toggled between HIGH and LOW to select the channel to be diagnosed.

Info on Protection

• Overvoltage Clamping: This feature limits the drain-source voltage and manages power dissipation effectively.
• Thermal Protection: The chip includes an integrated temperature sensor that shuts the device down during overtemperature conditions.
• Overcurrent Limitation: This function handles short circuits or excessive currents, automatically shutting down the device if overtemperature is detected. Once the temperature reaches back to normal operating state, the chip is automatically reset to normal mode.

HSO:

• Loss of Ground Protection: In the event of a loss of ground, the device automatically turns off or remains off to protect itself.
• Undervoltage Protection: The device turns off when the supply voltage drops below a certain threshold and turns back on when voltage is restored, with protection functions becoming active.
• Overvoltage Protection: This is managed by an integrated clamp mechanism, which limits the current through a ground resistor.
• Reverse Polarity Protection: The device uses resistors to limit current through the logic and sense transistors. However, no protection functions are active during reverse polarity.
• Overload Protection: This includes current limitation to maintain safe power levels and temperature sensors to prevent overheating. The device will switch off when necessary until it is manually reset via the input pin.

Info on Feedback

HS Feedback & Current Measurement:

The feedback signal can be read by following the steps below:

1. Select the HSO to Read – Toggle the DSEL_B2 pin LOW or HIGH, respectively.
2. Read the Applicable Channel Feedback ADC – The reading from the ADC will provide feedback as to the operating conditions of the HSO.

^Scaling factor for FCE = 1460, FCG = 2240.

LSO Feedback:

• • The status/feedback of the chip, indicating the state of the switch as either active (Logic HIGH) or inactive (Logic LOW), is communicated through the MCU pins. During normal operation (without thermal shutdown), the LSO_STAT pin’s logic is set to HIGH. In the case of a thermal shutdown, the LSO_STAT pin pulls its voltage down to GND, providing a LOW-level signal.

Application Recommendations

Inductive Loads

The DOs are protected against inductive flyback and will survive, but do not include a flyback diode. If desired, flyback can be more actively managed using the methods described below:

• (Most Control) Half Bridge with Control – Use an HSO and LSO in half bridge configuration and drive the load using the HSO. The body diode in the LSO will act as a flyback diode passively and can be actively PWM’d for more control of the load. Do not use the HSO as the flyback circuit.
• (Most Integrated) Half Bride with No Control – Use an HSO and LSO in half bridge configuration and drive the load using the HSO. Only use the LSO as a flyback diode. Do not use the HSO as the flyback circuit.
• Add An External Flyback Diode – Add an external flyback diode in parallel with the inductive load.

Half Bridge Configuration for FCE and FCG

A Half Bridge (or) a H-bridge is an electronic circuit designed to reverse the polarity of voltage applied to a load. These circuits are commonly utilized in robotics and various applications to enable DC motors to operate in both forward and reverse directions.

• FCE: For FCE, a half-bridge configuration is achieved by utilizing a single output pin where both HIGH and LOW states are available (Not present on focus SKU) or wiring a HSO and LSO together.
• FCG: For FCG, a half-bridge configuration is accomplished by appropriately wiring the output channel pins.

Software Configuration

The provided AudesseS32k3Unified.mex file is pre-configured with most of the necessary device drivers for general use. However, in some cases, you may need to customize the device drivers based on your specific hardware requirements. Below, we have listed some possible custom configurations that might be needed. If you have other configuration needs, please contact us.

Note: The changes must be done in the S32 Configuration tool.

Changing PWM Switching Frequency

There are several methods to adjust the PWM switching frequency. The switching frequency of the PWM is equal to the Master Bus frequency, which is calculated as:

PWM Frequency = CoreClock/ClockDividerValue/DefaultPeriod/MasterBusPrescaler

To adjust the PWM frequency:

1. Open the S32 Configuration Tool.
2. Select MCL from the left-side panel.
3. Navigate to Mcl Specific Configuration -> eMIOSCommon.
4. There are three eMIOSCommons, corresponding to eMIOS instances 0, 1, and 2, respectively. You can add custom eMIOS Master Buses here.

In the Audesse Sample Mex, there are five Emios Master Buses in total. EMIOS_0_MasteBus1 and EMIOS_1_MasteBus0 are used for the Emios PWN input capture reference clock. EMIOS_0_MasteBus0, EMIOS_1_MasteBus1 and EMIOS_2_MasteBus0 are used for the Emios PWM output reference clock, which can be found under: Pwm -> PwmChannelConfigSet -> Emios Instance -> PwmEmiosBusRef

Based on the previous equation, we can get PWM Frequency = 160MHz / 32000 / DIV_1 / DIV_1= 50kHz. By adjusting any of these values, you can achieve the desired control frequency for your actuator.