Enhanced General-Purpose Input/Output (EGPIO) Debugging and Error Handling#

This section provides practical guidance for debugging general-purpose input/output (GPIO) behavior on SiWx917 devices.

It explains how to verify electrical signals, diagnose driver failures, and resolve issues related to interrupts, pin configuration, and low-power operation.

Use these techniques when a GPIO does not toggle, interrupts fail to trigger, or behavior changes across power-state transitions.

Logic-Level Debugging#

Use an oscilloscope or logic analyzer to verify that a GPIO pin behaves as expected at the hardware level.

Checklist#

  • Confirm HIGH and LOW voltage levels match the configured pad voltage (1.8 V or 3.3 V).

  • Verify that edge transitions occur at expected intervals.

  • Check for glitches or noise, especially when switching between high-performance (HP), ultra-low-power (ULP), and ultra-ultra-low-power (UULP) domains.

  • Ensure the pin’s pull-up or pull-down resistor prevents floating inputs.

  • Confirm that the pin multiplexer (pinmux) is not mapping the pad to another peripheral.

These checks help isolate whether the issue originates in hardware or software.

Software-Level Debugging#

Use Simplicity Studio tools and WiSeConnect software development kit (SDK) features to analyze GPIO behavior at runtime.

Recommended Methods#

  • Peripheral inspection: View GPIO registers using the debugger.

  • Power analysis: Measure power consumption during power-state (PS2 through PS4) transitions.

  • Interrupt tracing: Ensure callbacks are registered and firing consistently.

  • RTOS-aware debugging: Ensure threads do not block or override GPIO access.

  • Logging: Add debug messages before and after GPIO operations.

Example:

printf("Toggling pin %d\n", gpio_pin);

Error Code Handling#

GPIO driver APIs in the WiSeConnect SDK return standardized status codes (sl_status_t) that indicate operation results. These codes help diagnose configuration issues, invalid parameters, and runtime conflicts.

Error Code

Description

Typical Cause

SL_STATUS_OK

Operation completed successfully

Normal operation

SL_STATUS_FAIL

General failure

Hardware or software fault

SL_STATUS_INVALID_PARAMETER

Invalid argument

Incorrect port, pin, or mode

SL_STATUS_BUSY

GPIO subsystem is busy

Concurrent access or pending interrupt

Example: Error Handling Workflow#

sl_status_t status = sl_gpio_set_configuration(gpio_pin_config);

if (status == SL_STATUS_INVALID_PARAMETER) {
  printf("Error: Invalid GPIO configuration. Check pin assignment.\n");
} else if (status != SL_STATUS_OK) {
  printf("Unexpected GPIO error (0x%lx). Resetting driver.\n", status);
  sl_gpio_driver_deinit();
  sl_gpio_driver_init();
}

Full Reset Procedure#

If GPIO behavior becomes undefined (for example, after a missed interrupt, pad misconfiguration, or improper sleep transition), reset the driver:

sl_gpio_driver_deinit();
sl_gpio_driver_init();

Tip: Always reapply pin configurations and callbacks after reinitialization.

Troubleshooting Workflow#

Follow this troubleshooting sequence when debugging GPIO issues on SiWx917 devices.

Step 1. Verify Hardware Setup#

  1. Confirm the correct pad voltage (1.8 V or 3.3 V).

  2. Ensure cables, jumpers, and solder joints are secure.

  3. Verify that ground and reference lines are connected correctly.

Step 2. Validate Software Configuration#

  1. Confirm the correct pin and port index.

  2. Check input or output mode, pull configuration, and pad attributes.

  3. Verify pinmux settings for multifunction pins.

  4. Ensure interrupts are enabled and callback pointers are valid.

Step 3: Monitor Runtime Behavior#

  1. Print GPIO states for debugging.

  2. Inspect registers such as GPIO->PORT[x].DATA.

  3. Log interrupt timestamps to detect missed or double-triggered events.

  4. Check thread or task interactions in RTOS environments.

Common Issues and Fixes#

Issue

Cause

Solution

Pin does not toggle

Incorrect mode or pinmux

Set direction and check pad mapping

Input reads incorrectly

Floating pin

Enable a pull-up or pull-down

Interrupt does not fire

Wrong trigger type or disabled interrupt

Reconfigure edge or level settings

ULP GPIO inactive in sleep

Using an HP pin in low-power mode

Use ULP or UULP GPIOs for wake-up events

Driver remains busy

ISR does not clear flags

Ensure interrupt status registers are cleared

Advanced Debugging Techniques#

Real-Time Trace#

Use embedded trace macrocell (ETM) or instrumentation trace macrocell (ITM) tracing, if supported by your evaluation board, to capture GPIO access patterns and interrupt timing.

Direct Register Inspection#

Read hardware registers to assess current GPIO states:

uint32_t port_state = GPIO->PORT[0].DATA;
printf("Port 0 state: 0x%08lx\n", port_state);

DMA and Peripheral Interaction#

When GPIO interacts with direct memory access (DMA)–driven peripherals:

  • Confirm DMA completion interrupts are serviced.

  • Ensure clock gating is configured for active domains.

Power-State Debugging#

GPIO behavior changes depending on whether the device is in PS4 (active), PS3 (light sleep), or PS2 (deep sleep).

Best Practices#

  • Use ULP GPIOs or UULP GPIOs for wake-up events.

  • Save and restore GPIO configurations across sleep cycles.

  • Disable unused pads to reduce leakage.

  • Validate wake-up timing using Simplicity Studio Energy Profiler.