ESH10000535 - Sparrow N-TOP Module

Overview

The ESH10000535 is the top-level control module for Sparrow-series test systems, providing precision analog measurement with programmable gain amplifiers, dual PWM/Tachometer control, calibration management, and LED status indication for compact test applications.

Description

The Sparrow N-TOP module serves as a sophisticated measurement and control hub featuring dual AD5592R multi-function I/O devices with programmable gain amplifiers (PGAs) for precision voltage measurement. The module supports 8 high-resolution ADC channels with automatic gain ranging, dual PWM output with tachometer feedback, UART communication, and visual LED status indication through an integrated RGB LED driver.

Key Features:

• 8-Channel Precision ADC with PGA: High-accuracy voltage measurement

  • 8 measurement channels (ADC_CH1 through ADC_CH8)
  • Programmable Gain Amplifier with 8 gain settings (1/8× to 16×)
  • Auto-ranging capability with hysteresis
  • Per-channel, per-gain calibration
  • 12-bit resolution (AD5592R)
  • 0-5V double range mode

• 12 Multi-Purpose I/O Channels: Bidirectional analog I/O

  • MPIO00-MPIO11: Configurable analog input/output
  • 12-bit ADC/DAC resolution
  • Supports analog and pseudo-digital modes
  • Individual gain and offset calibration

• Dual PWM/Tachometer Control: Precision frequency generation and measurement

  • 2× PWM outputs with frequency and duty cycle control
  • 2× Tachometer inputs for frequency measurement
  • Dedicated voltage references (PWM_VSET, TACH_VSET)
  • Microcontroller-based generation (MCU firmware)

• Advanced Calibration System: Per-channel, per-gain calibration storage

  • Persistent calibration by product ID, revision, serial number
  • 8 gain factors per ADC channel (64 calibration points total)
  • Automatic offset compensation per gain setting
  • Calibration channel for user access and modification

• LED Status Indication: Visual feedback system

  • 4× RGB LEDs (ANALOG_CONN, STATUS_1, STATUS_2, STATUS_3)
  • Configurable luminance and color
  • LP5012 LED driver with PWM control

• Communication Interfaces: UART and SPI protocol support

  • UART: RS232, configurable baudrate (default 9600)
  • SPI: High-speed communication (6 MHz)
  • Protocol enable/disable control

Hardware Details

Analog-to-Digital Converters:

• Chip: Analog Devices AD5592R (2 devices)
• Channels:
  • ADC1: 8 analog I/O channels (MPIO00-MPIO07)
  • ADC2: 6 analog I/O channels (2 internal ADC, MPIO08-MPIO11, PWM_VSET, TACH_VSET)
• Resolution: 12-bit ADC/DAC
• Communication: SPI bus @ 6 MHz
• SPI Chip Select:
  • ADC1: CS0
  • ADC2: CS1
• Voltage Range: 0-5V (double ADC/DAC range mode enabled)
• Features:
  • DoubleAdcRange: true
  • DoubleDacRange: true
  • ReadTemperature: false

Programmable Gain Amplifiers:

• Type: External PGA with GPIO-controlled gain selection
• Channels: 2 PGA paths (PGA1 for CH1-4, PGA2 for CH5-8)
• Gain Settings: 8 selectable gains
  • G_1_8: 1/8× (8.0 actual gain multiplier)
  • G_1_4: 1/4× (4.0 actual gain multiplier)
  • G_1_2: 1/2× (2.0 actual gain multiplier)
  • G_1: 1× (1.0 actual gain multiplier)
  • G_2: 2× (0.5 actual gain multiplier)
  • G_4: 4× (0.25 actual gain multiplier)
  • G_8: 8× (0.125 actual gain multiplier)
  • G_16: 16× (0.0625 actual gain multiplier)
• Control: 3-bit GPIO per PGA (G0, G1, G2)
• Calibration Multiplexer: 4 calibration modes per PGA
  • GND_GND: Both inputs grounded
  • GND_VREF: Ground to reference voltage
  • VREF_GND: Reference voltage to ground
  • INn_INp: Normal measurement mode

GPIO Expander:

• Chip: NXP PI4IOE5V6416
• I²C Address: 0x20
• Channels: 16 digital I/O (2 ports × 8 pins)
• Purpose: PGA gain control, calibration mux, protocol enable, programming control
• Communication: I²C bus
• Signals:
  • UART_ENn, SPI_ENn: Protocol enable (active-low)
  • UPDI_PGM: Microcontroller programming enable
  • SW0_PGA1, SW1_PGA1, SWEN_PGA1: PGA1 calibration mux
  • SW0_PGA2, SW1_PGA2, SWEN_PGA2: PGA2 calibration mux
  • G0_CH1, G1_CH1, G2_CH1: Channel 1-4 gain select
  • G0_CH2, G1_CH2, G2_CH2: Channel 5-8 gain select
  • RESETn: Global reset (active-low)

LED Driver:

• Chip: TI LP5012 RGB LED driver
• I²C Address: 0x14
• Channels: 12 (4 LEDs × 3 RGB)
• LEDs: ANALOG_CONN, STATUS_1, STATUS_2, STATUS_3
• Control: PWM-based intensity (0-255 per color)
• Default Luminance: 0.7 (70% brightness)
• Communication: I²C bus

PWM/Tachometer Controller:

• Chip: Microcontroller with PWM/Tach firmware
• I²C Address: 0x30
• Channels: 2 PWM outputs, 2 Tachometer inputs
• Features:
  • Frequency control (Hz)
  • Duty cycle control (0.0-1.0)
  • Enable/disable per channel
  • Frequency measurement (tachometer)
  • Firmware revision reporting
• Communication: I²C bus

Channel Naming Convention

All channels follow the naming pattern: {ModuleIndex}.ESH10000535.{ChannelName}

Where:

• {ModuleIndex} is the position of the module in the system (e.g., 0, 1, 2...)
• ESH10000535 is the module type identifier
• {ChannelName} is the specific channel name from the table below

Example: Module at position 0, ADC channel 1 would be: 0.ESH10000535.ADC_CH1

User-Accessible Channels

Total User Channels:

• Without PWM device: 28 channels (8 ADC_CH + 12 MPIO + 2 voltage outputs + 1 numeric result + 3 config + 1 UART + 1 calibration)
• With PWM device: 39 channels (28 + 11 PWM/Tach channels)

Note: PWM/Tachometer channels are only created if a PWM device is detected at I²C address 0x30 during module initialization.

Internal Channels (Not User-Accessible)

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

• ADC Channels (all HiddenSystemControl):
  • ADC1, ADC2: Internal ADC measurement channels for PGA readings
• LED RGB Channels (all HiddenSystemControl):
  • ANALOG_CONN_R, ANALOG_CONN_G, ANALOG_CONN_B
  • STATUS_1_R, STATUS_1_G, STATUS_1_B
  • STATUS_2_R, STATUS_2_G, STATUS_2_B
  • STATUS_3_R, STATUS_3_G, STATUS_3_B

Channel Configuration

MPIO Analog Configuration

Configure MPIO channels as analog inputs or outputs:

ConfigureChannels(new[] {
    new AnalogChannel {
        NetName = "0.ESH10000535.MPIO00",
        Enabled = true,
        Direction = DirectionTypes.IN,
        Gain = 1.0,
        Offset = 0.0,
        Resolution = 12
    }
});

// Read analog input
string[] voltage = GetValues(new[] { "0.ESH10000535.MPIO00" });
Console.WriteLine($"MPIO00: {voltage[0]}V");

Precision ADC with Gain Selection

Measure voltages with programmable gain:

// Set gain to 8× for measuring small signals
SetValues(
    new[] { "0.ESH10000535.GainMux" },
    new[] { "G_8" }  // 8× amplification
);

// Read ADC channel (1000 samples averaged)
string[] measurement = GetValues(new[] { "0.ESH10000535.ADC_CH1" });
double voltageV = double.Parse(measurement[0]);
Console.WriteLine($"Measured: {voltageV}V (with 8× gain)");

Auto-Ranging Mode

Enable automatic gain selection for optimal resolution:

// Enable auto-ranging
SetValues(
    new[] { "0.ESH10000535.AutoRange" },
    new[] { "true" }  // Automatic gain adjustment
);

// Read with auto-ranging (slower but optimal resolution)
string[] autoMeasurement = GetValues(new[] { "0.ESH10000535.ADC_CH2" });
Console.WriteLine($"Auto-ranged measurement: {autoMeasurement[0]}V");

Auto-Ranging Behavior:

• Automatically adjusts gain to keep signal within optimal ADC range
• Uses hysteresis to prevent oscillation between gain settings
• Changes gain by at most one step per measurement
• Upper thresholds: [30, 25, 10, 5, 2, 1, 0.2, 0.1] V (prevents clipping)
• Lower thresholds: [25, 10, 5, 2, 1, 0.2, 0.1, 0.01] V (improves resolution)
• Performance impact: Reduces measurement speed due to gain switching and re-sampling

PWM Configuration (if device available)

Generate PWM signals with configurable frequency and duty cycle:

// Configure PWM1 for 1kHz at 50% duty cycle
SetValues(
    new[] {
        "0.ESH10000535.PWM1_REQ_FREQ",
        "0.ESH10000535.PWM1_DUTY_CYCLE",
        "0.ESH10000535.PWM1_ENABLE"
    },
    new[] {
        "1000",   // 1000 Hz
        "0.5",    // 50% duty cycle
        "true"    // Enable output
    }
);

// Read actual frequency
string[] actualFreq = GetValues(new[] { "0.ESH10000535.PWM1_ACTUAL_FREQ" });
Console.WriteLine($"PWM1 actual frequency: {actualFreq[0]} Hz");

Tachometer Measurement

Measure frequency of external signals:

// Set tachometer reference voltage
SetValues(
    new[] { "0.ESH10000535.TACH_VSET" },
    new[] { "3.3" }  // 3.3V reference for logic level
);

// Read tachometer frequency
string[] tachFreq = GetValues(new[] { 
    "0.ESH10000535.TACH1_ACTUAL_FREQ",
    "0.ESH10000535.TACH2_ACTUAL_FREQ"
});
Console.WriteLine($"TACH1: {tachFreq[0]} Hz");
Console.WriteLine($"TACH2: {tachFreq[1]} Hz");

Programming Interface

Measure with Fixed Gain:

// Set specific gain
SetValues(
    new[] { 
        "0.ESH10000535.GainMux",
        "0.ESH10000535.AutoRange"
    },
    new[] { 
        "G_1",     // Unity gain
        "false"    // Disable auto-range
    }
);

// Read ADC channels
string[] values = GetValues(new[] {
    "0.ESH10000535.ADC_CH1",
    "0.ESH10000535.ADC_CH2",
    "0.ESH10000535.ADC_CH3"
});

foreach (var val in values)
{
    Console.WriteLine($"Measurement: {val}V");
}

Multi-Channel Acquisition with Numeric Results:

// Configure numeric result channel for high-speed acquisition
ConfigureChannels(new[] {
    new NumericResultChannel {
        NetName = "0.ESH10000535.NumericResult",
        Enabled = true,
        NumberOfSamples = 10000,
        SampleRate = 10000,  // 10 kHz sampling
        TargetNetName = "0.ESH10000535.ADC_CH1",
        ReducedSet = true,   // Get statistics
        MultiChannel = false
    }
});

// Acquire data
string[] result = GetValues(new[] { "0.ESH10000535.NumericResult" });
List<NumericResult> data = NumericResult.FromBase64(result[0]);

// Process statistics
foreach (var channel in data)
{
    Console.WriteLine($"{channel.NetName}:");
    Console.WriteLine($"  Mean: {channel.Mean:F6}V");
    Console.WriteLine($"  Min: {channel.Min:F6}V");
    Console.WriteLine($"  Max: {channel.Max:F6}V");
    Console.WriteLine($"  StdDev: {channel.StdDev:F6}V");
}

UART Communication:

// Configure UART
ConfigureChannels(new[] {
    new UartChannel {
        NetName = "0.ESH10000535.UART",
        Enabled = true,
        Baudrate = 115200,  // Change from default 9600
        BusType = UartBusTypes.RS232
    }
});

// Send command
SetValues(
    new[] { "0.ESH10000535.UART" },
    new[] { "ID?\r\n" }
);

// Read response
Thread.Sleep(100);
string[] response = GetValues(new[] { "0.ESH10000535.UART" });
Console.WriteLine($"Device response: {response[0]}");

Calibration Management:

// Read current calibration table
string[] calData = GetValues(new[] { "0.ESH10000535.CALIBRATION" });
CalibrationTable cal = SerializableHelpers.CreateFromBase64<CalibrationTable>(calData[0]);

// Display calibration for ADC_CH1 at gain G_1
var ch1Cal = cal.CalData.Where(r => r.Key.Contains("ADC_CH1") && r.Tag.ToString() == "G_1");
foreach (var row in ch1Cal)
{
    Console.WriteLine($"{row.Key} @ {row.Tag}: Gain={row.Gain}, Offset={row.Offset}");
}

// Perform calibration (requires known reference voltages)
SetValues(
    new[] { "0.ESH10000535.PERFORM_CAL" },
    new[] { "true" }  // Triggers calibration sequence
);

// Save calibration (password protected)
SetValues(
    new[] { "0.ESH10000535.STORE_CAL" },
    new[] { "ESH10000535" }  // Password = module type name
);

LED Control: Internal LED control is managed automatically:

• ANALOG_CONN: Indicates analog connection status (Teal when initialized, Red during error)
• STATUS_1: Green during GetValues operations
• STATUS_2: Black (off) by default
• STATUS_3: Black (off) by default, can indicate UART/SPI activity

Programmable Gain Amplifier (PGA) System

The module features a sophisticated gain control system with 8 selectable gain settings:

Gain Settings and Applications:

Gain Control Implementation:

• Each PGA has 3 GPIO control lines (G0, G1, G2) for 8 combinations
• PGA1 controls channels ADC_CH1-4
• PGA2 controls channels ADC_CH5-8
• Gain applied before ADC conversion (analog domain amplification)
• Calibration factors stored per-channel, per-gain for maximum accuracy

Calibration System

The module implements a comprehensive per-channel, per-gain calibration system:

Calibration Table Structure:

• 64 ADC channel calibration entries: 8 channels × 8 gain settings
• 2 ADC absolute offset entries: ADC1_ABS_OFFSET, ADC2_ABS_OFFSET (per gain)
• 12 MPIO calibration entries: MPIO00-11 (single gain)
• 2 voltage output calibration entries: PWM_VSET, TACH_VSET

Calibration Storage:

• Persistent storage by module identity (ProductID, Revision, SerialNumber)
• Automatic loading on module Reset()
• User-accessible via CALIBRATION channel
• Password-protected save operation (password: "ESH10000535")

Calibration Process:

1. Automatic Calibration (PERFORM_CAL = true):

   • For each gain setting (G_1_8 through G_16):
     • Route calibration mux to GND_GND mode
     • Acquire 10,000 samples per channel
     • Calculate mean offset error
     • Store offset correction in calibration table
   • Saves calibration to persistent storage automatically

2. Manual Calibration Adjustment:

   • Read calibration table via CALIBRATION channel
   • Modify gain and offset for specific channels/gains
   • Write updated table back to CALIBRATION channel
   • Call SaveCalibrationValues() via STORE_CAL

Calibration Application:

• Offset applied before gain multiplication: Result = (ADC_Reading + Offset) × Gain
• Calibration automatically applied on all measurements
• Per-gain calibration ensures accuracy across full measurement range

Auto-Ranging Algorithm

The module features intelligent auto-ranging with hysteresis to prevent oscillation:

Algorithm Behavior:

1. Measure signal with current gain setting
2. Check if signal exceeds upper threshold for current gain
   • If yes, decrease gain by one step (less amplification)
3. Check if signal below lower threshold for current gain
   • If yes, increase gain by one step (more amplification)
4. If within hysteresis window, keep current gain
5. Maximum recursion depth: 8 iterations to find optimal gain

Hysteresis Thresholds:

Gain     Upper    Lower    Hysteresis Window
G_1_8:   30.0V    25.0V    25.0-30.0V
G_1_4:   25.0V    10.0V    10.0-25.0V
G_1_2:   10.0V     5.0V     5.0-10.0V
G_1:      5.0V     2.0V     2.0-5.0V
G_2:      2.0V     1.0V     1.0-2.0V
G_4:      1.0V     0.2V     0.2-1.0V
G_8:      0.2V     0.1V     0.1-0.2V
G_16:     0.1V    0.01V    0.01-0.1V

Example: Measuring 1.5V signal:

• Initial gain: G_1 (1×)
• 1.5V is within hysteresis window (2.0V-5.0V) → Keep G_1
• Final measurement: 1.5V at G_1

Example: Measuring 8mV signal:

• Initial gain: G_1 (1×)
• 0.008V < 2.0V (lower threshold) → Increase to G_2
• 0.008V < 1.0V (lower threshold) → Increase to G_4
• 0.008V < 0.2V (lower threshold) → Increase to G_8
• 0.008V < 0.1V (lower threshold) → Increase to G_16
• 0.008V is within hysteresis window (0.01V-0.1V) → Keep G_16
• Final measurement: 8mV at G_16 (optimal resolution)

Error Handling

The module validates operations and provides error messages:

• Invalid NetName: Throws exception if channel does not exist
• Unsupported Channel Type: Throws exception for unrecognized channel types
• I²C Communication Errors: Logged and propagated to caller
• SPI Communication Errors: AD5592R read/write errors logged
• Calibration Errors: Validates calibration table structure and gain factor keys
• Auto-Range Recursion Limit: Maximum 8 iterations to prevent infinite loops
• PWM Device Not Found: Logged as error if expected device at 0x30 is missing

Best Practices

1. Gain selection: Choose appropriate gain for expected signal range
   • Use auto-ranging for unknown signals (slower but automatic)
   • Use fixed gain for known signals (faster, consistent performance)
2. Calibration: Perform calibration after hardware changes or environmental shifts
3. Sample averaging: Use NumericResultChannel for high sample counts (>1000 samples)
4. MPIO direction: Always configure direction (IN/OUT) before use
5. PWM device detection: Check for PWM channels before using (may not be present on all units)
6. Voltage references: Set PWM_VSET and TACH_VSET before using PWM/Tach features
7. UART configuration: Verify baudrate and bus type before communication
8. LED monitoring: Observe LED colors for system status (Green = active read, Red = error)
9. Calibration backup: Export calibration table before making changes
10. Programming mode: Only enable PROG_EN when intentionally programming microcontroller

Module Initialization Sequence

On Reset(), the module performs:

1. Clear existing channel list
2. Setup LED driver:
   • Create LP5012 at I²C address 0x14
   • Initialize 4 RGB LEDs (ANALOG_CONN, STATUS_1, STATUS_2, STATUS_3)
   • Set initial colors: All Red (initializing state)
3. I²C device scan: Scan for PWM/Tach device at 0x30
4. Setup PWM/Tachometer (if device found at 0x30):
   • Create PwmTacho device
   • Reset PWM/Tach controller
   • Add 11 PWM/Tach channels:
     • PWM1: ACTUAL_FREQ, REQ_FREQ, DUTY_CYCLE, ENABLE
     • PWM2: ACTUAL_FREQ, REQ_FREQ, DUTY_CYCLE, ENABLE
     • TACH: TACH1_ACTUAL_FREQ, TACH2_ACTUAL_FREQ
     • PWMTACH_FW_REVISION
5. Setup GPIO expander:
   • Create PI4IOE5V6416 at I²C address 0x20
   • Configure 16 control signals (UART/SPI enable, PGA control, mux control, reset)
   • Perform reset sequence (toggle RESETn 10 times)
6. Setup ADC devices:
   • ADC1 (SPI CS0): 8 MPIO channels (MPIO00-07), bidirectional
   • ADC2 (SPI CS1): 2 internal ADC channels + 4 MPIO (MPIO08-11) + PWM_VSET + TACH_VSET
   • Enable double ADC/DAC range mode (0-5V)
   • Disable internal temperature sensing
   • Reset and update both ADC devices
7. Load calibration table from persistent storage
8. Add public measurement channels:
   • ADC_CH1 through ADC_CH8 (precision ADC with PGA)
9. Perform automatic calibration: PerformCalibration() for all gains
10. Apply calibration values to all channels
11. Add NumericResult channel with analog targets populated
12. Add configuration channels:
    • AutoRange (digital, default: true)
    • GainMux (multiplexer, default: G_1)
    • PROG_EN (digital, default: false)
13. Add UART channel (RS232, 9600 baud, /dev/serial0)
14. Add calibration management channels:
    • PERFORM_CAL (digital trigger)
    • STORE_CAL (password-protected register)
    • CALIBRATION (calibration table access)
15. Update LED colors:
    • ANALOG_CONN: Teal (ready)
    • STATUS_1, STATUS_2, STATUS_3: Black (off)

Typical Use Cases

1. Precision Voltage Measurement:

// Measure millivolt-level signal with optimal resolution
SetValues(
    new[] { 
        "0.ESH10000535.GainMux",
        "0.ESH10000535.AutoRange"
    },
    new[] { 
        "G_16",    // 16× gain for mV signals
        "false"    // Fixed gain
    }
);

string[] voltage = GetValues(new[] { "0.ESH10000535.ADC_CH1" });
double millivolts = double.Parse(voltage[0]) * 1000;
Console.WriteLine($"Measured: {millivolts:F3} mV");

2. Multi-Range Voltage Characterization:

// Measure across multiple gain settings for linearity check
void CharacterizeLinearity(string channelNetName)
{
    var gains = new[] { "G_1_8", "G_1_4", "G_1_2", "G_1", "G_2", "G_4", "G_8", "G_16" };

    Console.WriteLine("Gain Setting | Measured Voltage");
    Console.WriteLine("-------------|------------------");

    foreach (var gain in gains)
    {
        SetValues(
            new[] { "0.ESH10000535.GainMux", "0.ESH10000535.AutoRange" },
            new[] { gain, "false" }
        );

        Thread.Sleep(100);  // Allow settling

        string[] measurement = GetValues(new[] { channelNetName });
        Console.WriteLine($"{gain,-12} | {measurement[0]} V");
    }
}

CharacterizeLinearity("0.ESH10000535.ADC_CH1");

3. PWM Generation for Motor Control:

// Generate variable speed PWM for motor control
void SetMotorSpeed(double speedPercent)
{
    double frequency = 20000;  // 20 kHz PWM
    double dutyCycle = speedPercent / 100.0;

    SetValues(
        new[] {
            "0.ESH10000535.PWM_VSET",        // Motor driver voltage
            "0.ESH10000535.PWM1_REQ_FREQ",
            "0.ESH10000535.PWM1_DUTY_CYCLE",
            "0.ESH10000535.PWM1_ENABLE"
        },
        new[] {
            "5.0",                            // 5V logic level
            frequency.ToString(),
            dutyCycle.ToString("F3"),
            "true"
        }
    );

    // Verify frequency
    string[] actualFreq = GetValues(new[] { "0.ESH10000535.PWM1_ACTUAL_FREQ" });
    Console.WriteLine($"Motor speed: {speedPercent}% @ {actualFreq[0]} Hz");
}

SetMotorSpeed(75);  // 75% speed

4. Tachometer-Based Speed Control:

// Closed-loop speed control using tachometer feedback
void ClosedLoopSpeedControl(double targetRPM)
{
    const double PulsesPerRevolution = 4;  // Encoder resolution
    double targetFreq = (targetRPM / 60.0) * PulsesPerRevolution;

    // Initial PWM settings
    double dutyCycle = 0.5;

    for (int i = 0; i < 10; i++)
    {
        // Read current speed
        string[] tachFreq = GetValues(new[] { "0.ESH10000535.TACH1_ACTUAL_FREQ" });
        double measuredFreq = double.Parse(tachFreq[0]);
        double measuredRPM = (measuredFreq / PulsesPerRevolution) * 60.0;

        // Simple proportional control
        double error = targetRPM - measuredRPM;
        dutyCycle += error * 0.001;  // P-gain
        dutyCycle = Math.Max(0.0, Math.Min(1.0, dutyCycle));  // Clamp

        // Update PWM
        SetValues(
            new[] { "0.ESH10000535.PWM1_DUTY_CYCLE" },
            new[] { dutyCycle.ToString("F3") }
        );

        Console.WriteLine($"Target: {targetRPM} RPM, Measured: {measuredRPM:F1} RPM, Duty: {dutyCycle:F3}");

        Thread.Sleep(100);
    }
}

ClosedLoopSpeedControl(3000);  // Target 3000 RPM

5. Multi-Channel Data Acquisition:

// Acquire synchronized multi-channel data
void AcquireMultiChannelData()
{
    // Configure for mid-range signals
    SetValues(
        new[] { "0.ESH10000535.GainMux", "0.ESH10000535.AutoRange" },
        new[] { "G_1", "false" }
    );

    // Read all 8 ADC channels
    string[] values = GetValues(new[] {
        "0.ESH10000535.ADC_CH1",
        "0.ESH10000535.ADC_CH2",
        "0.ESH10000535.ADC_CH3",
        "0.ESH10000535.ADC_CH4",
        "0.ESH10000535.ADC_CH5",
        "0.ESH10000535.ADC_CH6",
        "0.ESH10000535.ADC_CH7",
        "0.ESH10000535.ADC_CH8"
    });

    Console.WriteLine("Multi-Channel Acquisition:");
    for (int i = 0; i < values.Length; i++)
    {
        Console.WriteLine($"  CH{i+1}: {values[i]} V");
    }
}

AcquireMultiChannelData();

Debugging and Troubleshooting

Problem: ADC readings unstable or noisy

• Check: Appropriate gain setting for signal amplitude
• Check: Auto-ranging may be causing gain switching (disable for stable signals)
• Try: Use NumericResultChannel with averaging for cleaner measurements
• Verify: Calibration is current and appropriate for gain setting

Problem: Auto-ranging not converging

• Check: Signal may be outside measurement range (too high or too low)
• Check: Signal may be oscillating around threshold boundaries
• Action: Disable auto-ranging and manually select appropriate gain
• Verify: Signal is within 0-5V ADC input range after gain application

Problem: Calibration values seem incorrect

• Check: PERFORM_CAL was run with proper reference connections
• Check: Calibration mux was in correct mode during calibration
• Action: Re-run calibration sequence
• Verify: Save calibration with STORE_CAL after performing calibration

Problem: PWM/Tachometer channels not available

• Check: PWM device detected at I²C address 0x30 during initialization
• Action: Verify hardware includes PWM/Tach controller
• Note: Not all units may have this option installed

Problem: UART communication fails

• Check: UART_ENn GPIO is set to false (enabled)
• Check: Baudrate matches connected device
• Check: /dev/serial0 device exists and has proper permissions
• Verify: Hardware UART connections are correct

Problem: SPI communication errors with ADCs

• Check: SPI clock speed is 6 MHz (may need reduction for long cables)
• Check: SPI chip select signals routing correctly
• Action: Reset module to reinitialize SPI communication
• Verify: GPIO expander is responding (I²C 0x20)

Comparison with Standard ADC Modules

Revision History

• ESH10000535: Current production version
  • Dual AD5592R ADCs (8 MPIO + 6 MPIO + voltage outputs)
  • 8 precision ADC channels with programmable gain amplifiers
  • 8 gain settings (1/8× to 16×)
  • Auto-ranging with hysteresis algorithm
  • Per-channel, per-gain calibration (64 calibration points)
  • Optional PWM/Tachometer controller (dual channel)
  • LP5012 LED driver (4 RGB LEDs)
  • PI4IOE5V6416 GPIO expander for control
  • UART communication (RS232)
  • SPI @ 6 MHz for ADC communication
  • Persistent calibration storage