Livt.IO

tests/i2c/I2CConfiguredTimeoutTest.lvt

namespace Livt.IO.Tests

using Livt.IO

/**
 * Bounds stretching, releases the bus, and allows another transaction after failure.
 */
@Test
@Context(ClockFrequency = 100MHz)
component I2CConfiguredTimeoutTest
{
	// Owned fixture and controller share the annotated clock/reset context.
	bus: I2CTimeoutBus
	master: I2CMaster<100000Hz, 40us>

	/**
	 * Owns the observing bus and master in this test clock context.
	 */
	new()
	{
		this.bus = new I2CTimeoutBus()
		this.master = new I2CMaster<100000Hz, 40us>(this.bus)
	}

	/**
	 * Waits for completion with a bounded polling loop so a regression cannot hang the test.
	 */
	fn WaitForCommand()
	{
		var attempts = 0

		while (this.master.IsBusy() && attempts < 20000) {
			state {
				attempts++
			}
		}

		assert !this.master.IsBusy()
	}

	/**
	 * Checks bounded START, STOP, write and read failures followed by successful reuse.
	 */
	@Test
	fn TimesOutAndRecovers()
	{
		for (var command = 0; command < 4; command++) {
			this.bus.HoldClock()
			Simulation.Wait(10)
			var start = this.bus.Ticks()
			var accepted = false

			match (command)
			{
				0 =>
				{
					accepted = this.master.BeginStart()
				}
				1 =>
				{
					accepted = this.master.BeginStop()
				}
				2 =>
				{
					accepted = this.master.BeginWriteByte(0x00)
				}
				_ =>
				{
					accepted = this.master.BeginReadByte(false)
				}
			}

			assert accepted
			this.WaitForCommand()
			var elapsed = this.bus.Ticks() - start
			assert elapsed >= 4000
			assert elapsed < 6200
			assert this.master.HasResult()
			assert this.master.HasTimedOut()
			assert !this.master.WasAckReceived()
			assert !this.master.WasNackReceived()
			assert this.master.GetReadByte() == 0x00
			assert this.bus.LinesReleased()

			this.bus.ReleaseClock()
			Simulation.Wait(10)
			assert this.master.BeginStart()
			assert !this.master.HasTimedOut()
			this.WaitForCommand()
			assert this.master.HasResult()
			assert !this.master.HasTimedOut()
			assert this.master.BeginStop()
			this.WaitForCommand()
			assert !this.master.HasTimedOut()
			assert this.bus.LinesReleased()
		}
	}
}