ESH10000239 - I2C Long Range 4ch Module

Overview

The ESH10000239 is a long-range I²C extension module providing 4 independent I²C channels with power control, link status monitoring, and automatic discovery capabilities for connecting remote I²C devices over extended distances.

Description

The I2C Long Range 4ch module extends I²C communication beyond standard distance limitations using dedicated line drivers/repeaters. Each of the 4 channels features independent power control, reset capability, and real-time link status detection, making it ideal for connecting to remote test fixtures, DUTs, or distributed sensor networks.

Key Features:

• 4 Long-Range I²C Channels: Extended distance I²C communication

  • Individual power enable control per channel
  • Per-channel reset capability
  • Real-time link status monitoring
  • Automatic power management on link failure

• Power Management: Smart downstream power control

  • PWREN1-4: Individual power enable outputs
  • Automatic power-off on link loss
  • Power sequencing during module discovery
  • Overcurrent/fault detection

• Link Status Monitoring: Real-time connection health

  • LINK1-4: Active-low link detect inputs (ReadOnlySystemControl)
  • Automatic link polling during discovery
  • 100ms timeout for link establishment
  • FAULTn: Global fault indicator

• Module Discovery: Automatic downstream module detection

  • Enumerates connected modules on each I²C channel
  • Power-on sequence with link verification
  • Reset release timing control
  • Fault-tolerant discovery (continues on channel errors)

Hardware Details

Line Drivers:

• Type: Long-range I²C repeaters/extenders (specific chip TBD)
• Channels: 4 independent I²C buses
• Distance: Extended beyond standard I²C limits (typically 10m+ vs. <1m standard)
• Features:
  • Active buffering
  • Rise-time acceleration
  • Bidirectional communication
  • Link status reporting

GPIO Expander:

• Chip: NXP PI4IOE5V6416
• I²C Address: 0x20
• Source Bus: "OWN" (module's own I²C bus, not routed through parent)
• Purpose: Power control, reset control, link monitoring, LED control

Power Distribution:

• Downstream power switching per channel
• Controlled via PWREN1-4 outputs
• Protection features (fault detection)

Channel Naming Convention

All channels follow the naming pattern: {ModuleIndex}.ESH10000239.{ChannelName}

Where:

• {ModuleIndex} is the position of the module in the system (e.g., 0, 1, 2...)
• ESH10000239 is the module type identifier
• {ChannelName} is the specific channel name from the table below

Example: Module at position 0, power enable for channel 1 would be: 0.ESH10000239.PWREN1

User-Accessible Channels

Total User Channels: 9 (4 power enables + 4 link status + 1 fault indicator)

Note: LINK channels are active-low - a value of false indicates a successful connection.

Internal Channels (Not User-Accessible)

The following channels are used for internal system control and are hidden from users:

• GPIO Expander Signals (all HiddenSystemControl):
  • RESET1n-RESET4n: Per-channel reset control (active-low)
  • LED_R: Red status LED
  • LED_G: Green status LED
  • IOCTRL: I/O control signal

Data Bus Integration

The module provides a data bus with 4 I²C channel signals:

• Signal Type: I2C
• NetName Pattern: {ModuleIndex}.ESH10000239.I2C{00-03}
• Purpose: Routes I²C buses to downstream modules
• Usage: Automatic routing during module discovery and communication

Module Discovery Process

The DiscoverModules() method implements an automatic discovery sequence for each of the 4 I²C channels:

Discovery Sequence per Channel:

1. Setup GPIO Expander: Initialize control signals (if first run)
2. Check Existing Link: Read current LINK status
3. Enable Power: Set PWREN = true
4. Wait for Power Stabilization: 2ms delay
5. Release Reset: Set RESETn = true
6. Poll Link Status: Wait up to 100ms for LINK = false (connected)
7. Verify Link:
   • Success: Proceed to enumerate downstream modules
   • Failure: Disable power (PWREN = false), log warning, continue to next channel
8. Enumerate Modules: Call CommonMethods.DiscoverModules() for connected channel
9. Add to Collection: Add discovered modules to parent's module list

Example Discovery Output:

INFO: LINK1 status: true (disconnected)
INFO: Enabling power on channel 1
INFO: Link established on channel 1
INFO: Discovered 2 modules on channel 1
WARN: No Link on channel 2 found. Disabling power
INFO: Link established on channel 3

Programming Interface

Enable Channel Power:

SetValues(
    new[] { "0.ESH10000239.PWREN1", "0.ESH10000239.PWREN2" },
    new[] { "true", "true" }  // Power on channels 1 and 2
);

Check Link Status:

string[] status = GetValues(new[] {
    "0.ESH10000239.LINK1",
    "0.ESH10000239.LINK2",
    "0.ESH10000239.LINK3",
    "0.ESH10000239.LINK4"
});
// status[i] = "false" means link is CONNECTED (active-low)
// status[i] = "true" means link is DISCONNECTED

bool channel1Connected = bool.Parse(status[0]) == false;
bool channel2Connected = bool.Parse(status[1]) == false;

Monitor Fault Status:

string[] fault = GetValues(new[] { "0.ESH10000239.FAULTn" });
bool faultDetected = bool.Parse(fault[0]) == false;  // Active-low

if (faultDetected)
{
    Console.WriteLine("WARNING: Fault detected on module");
    // Take corrective action
}

Power Cycle a Channel:

// Power off
SetValues(
    new[] { "0.ESH10000239.PWREN1" },
    new[] { "false" }
);
Thread.Sleep(100);  // Wait for power-down

// Power on
SetValues(
    new[] { "0.ESH10000239.PWREN1" },
    new[] { "true" }
);
Thread.Sleep(2);  // Wait for power stabilization

// Check link
string[] link = GetValues(new[] { "0.ESH10000239.LINK1" });
bool connected = bool.Parse(link[0]) == false;  // Active-low

Configure Channels:

ConfigureChannels(new[] {
    new DigitalChannel {
        NetName = "0.ESH10000239.PWREN1",
        Enabled = true,
        Direction = DirectionTypes.OUT,
        DefaultValue = false,  // Power off by default
        Value = false
    },
    new DigitalChannel {
        NetName = "0.ESH10000239.PWREN2",
        Enabled = true,
        Direction = DirectionTypes.OUT,
        DefaultValue = false,
        Value = false
    }
});

Link Detection Mechanism

The module uses a polling-based link detection with timeout:

private bool PollUntilState(string name, bool state, int timeout = 1000)
{
    var start = DateTime.Now;
    while (DateTime.Now.Subtract(start).TotalMilliseconds < timeout)
    {
        gpio.Invalidate();  // Force re-read from hardware
        if (bool.Parse(gpio.GetValues([name])[0]).Equals(state))
            return true;
        System.Threading.Thread.Sleep(10);  // Poll every 10ms
    }
    return false;  // Timeout
}

Usage during Discovery:

// Wait for link to become active (false = connected)
if (PollUntilState(GetFullNetName("LINK1"), false, 100))
{
    // Link established within 100ms
}
else
{
    // Link failed to establish, disable power
}

Error Handling

The module implements fault-tolerant operation:

• Channel-Level Isolation: Failure on one channel does not affect others
• Automatic Power Management: Disables power on link failure
• Graceful Degradation: Discovery continues even if some channels fail
• Comprehensive Logging: Error, warning, and info messages for troubleshooting

Error Scenarios:

1. No Link Detected:

   • Power remains off
   • Warning logged: "No Link on channel X found. Disabling power"
   • Discovery continues to next channel

2. Discovery Exception:

   • Exception caught and logged
   • Power disabled for faulted channel
   • Discovery continues to next channel

3. GPIO Communication Failure:

   • Logged as error
   • May retry based on I²C layer retry logic

Best Practices

1. Check link status before operations: Always verify LINK = false before I²C transactions
2. Monitor link during operation: Periodically poll link status for connection health
3. Power sequencing: Wait 2ms after enabling power before releasing reset
4. Link establishment timeout: Allow up to 100ms for link to stabilize
5. Fault monitoring: Check FAULTn periodically for system-level issues
6. Power management: Disable power when channel is unused to save energy
7. Discovery on reset: Call DiscoverModules() after module reset to enumerate downstream devices
8. Active-low signals: Remember LINK and FAULTn are active-low (false = active/connected)
9. Graceful handling: Expect some channels may not have devices connected
10. Cable length: Test I²C communication reliability at maximum expected cable length

Module Initialization Sequence

On Reset(), the module performs:

1. (Empty Reset): Reset() method is currently empty
2. Discovery-based Init: Actual initialization occurs in DiscoverModules()

On DiscoverModules(), the module performs:

1. Clear module list
2. Setup GPIO expander with control signals:
   • RESET1n-RESET4n (active-low reset outputs, default=false)
   • PWREN1-4 (power enable outputs, default=false)
   • LINK1-4 (link detect inputs, read-only)
   • FAULTn (fault indicator input, read-only)
   • LED_R, LED_G (status LEDs)
   • IOCTRL (I/O control)
3. For each of 4 channels (i=1 to 4):
   • Read initial LINK status
   • Enable power (PWREN = true)
   • Wait 2ms for power stabilization
   • Release reset (RESETn = true)
   • Poll for link (wait up to 100ms for LINK = false)
   • If link established:
     • Enumerate downstream modules
     • Add to module collection
   • If link failed:
     • Disable power (PWREN = false)
     • Log warning
     • Continue to next channel

Typical Use Cases

1. Test Fixture Interface:

// Connect to 4 remote test fixtures
module.DiscoverModules();
// Modules on each I²C channel are now available

2. Distributed Sensor Network:

// Enable power to all sensor nodes
SetValues(
    new[] { "0.ESH10000239.PWREN1", "0.ESH10000239.PWREN2",
            "0.ESH10000239.PWREN3", "0.ESH10000239.PWREN4" },
    new[] { "true", "true", "true", "true" }
);

// Monitor link health
while (running)
{
    string[] links = GetValues(new[] {
        "0.ESH10000239.LINK1", "0.ESH10000239.LINK2",
        "0.ESH10000239.LINK3", "0.ESH10000239.LINK4"
    });

    for (int i = 0; i < 4; i++)
    {
        if (bool.Parse(links[i]) == true)  // Disconnected
        {
            Console.WriteLine($"WARNING: Channel {i+1} link lost!");
        }
    }

    Thread.Sleep(1000);  // Check every second
}

3. Hot-Plug Detection:

// Poll for new device connections
while (true)
{
    string[] links = GetValues(new[] { "0.ESH10000239.LINK1" });
    bool connected = bool.Parse(links[0]) == false;

    if (connected && !wasConnected)
    {
        // Device just connected
        Console.WriteLine("Device detected on channel 1");
        module.DiscoverModules();  // Re-enumerate
    }

    wasConnected = connected;
    Thread.Sleep(500);
}

Debugging and Troubleshooting

Problem: Link status always shows disconnected

• Check: Cable connection and length
• Check: Power enable is set to true
• Check: Reset line has been released (RESETn = true)
• Check: Downstream device is powered and functional
• Try: Increase polling timeout beyond 100ms

Problem: Fault indicator is active

• Check: Overcurrent condition on any channel
• Check: Short circuit on downstream devices
• Action: Disable power, investigate hardware issue

Problem: DiscoverModules() finds no modules

• Check: Link status for each channel
• Check: Cable continuity
• Check: Downstream module I²C addresses don't conflict
• Try: Manual power cycle of problematic channels

Problem: Intermittent communication errors

• Check: Cable length and quality
• Check: I²C pull-up resistors on downstream devices
• Check: Ground connection integrity
• Try: Reduce I²C bus speed (if configurable on downstream devices)

Comparison with Standard I²C

Revision History

• ESH10000239: Current production version
  • 4 long-range I²C channels
  • Per-channel power control and reset
  • Link status monitoring
  • Automatic module discovery
  • Fault detection