ESH10000028 - AMUX Module

Overview

The ESH10000028 is an analog multiplexer module providing flexible signal routing between 10 independent multiplexers (A-K) with additional bus multiplexing for I²C, UART, SPI, and JTAG communication.

Description

The AMUX Module features 10 independent 8:1 analog multiplexers that can be interconnected through cross-connect switches. Additionally, it provides bus routing for digital communication protocols, enabling flexible test configurations and signal path management.

Key Features:

• 10 Independent 8:1 Multiplexers (MUX_A through MUX_K):

  • 8 input channels per multiplexer
  • Software-selectable routing
  • Cross-connect switches for inter-MUX connections

• 6 Cross-Connect Switches:

  • AC: Connects MUX A to MUX C
  • BD: Connects MUX B to MUX D
  • CE: Connects MUX C to MUX E
  • DF: Connects MUX D to MUX F
  • EG: Connects MUX E to MUX G
  • FH: Connects MUX F to MUX H
  • GJ: Connects MUX G to MUX J
  • HK: Connects MUX H to MUX K

• Bus Multiplexing: Route communication buses to different MUX groups

  • I2C routing
  • UART routing (ABEF or CDGH groups)
  • SPI routing (ABEF or CDGH groups)
  • JTAG routing (ABEF or CDGH groups)

• Communication Interfaces:

  • External I²C channel
  • UART channel (RS232, configurable baudrate)
  • SPI channel

Hardware Details

GPIO Expanders:

• Chip: NXP PI4IOE5V6416 (4 chips)
• I²C Addresses:
  • U26: 0x20 (Int_I2C0) - MUX select signals A-E
  • U27: 0x21 (Int_I2C0) - MUX select signals F-K, cross-connects AC/BD
  • U28: 0x20 (Int_I2C1) - Cross-connects EG/FH/CE/DF/GJ/HK, output enables
  • U29: 0x21 (Int_I2C1) - Bus routing control, status LED
• Purpose: Multiplexer channel selection and output enable control

Multiplexer Chips:

• Type: Analog multiplexers (8:1)
• Control Signals: 3-bit select (S0, S1, S2) per MUX
• Output Enable: Active-low per MUX

Channel Naming Convention

All channels follow the naming pattern: {ModuleIndex}.ESH10000028.{ChannelName}

Example: Module at position 1, MUX A would be: 1.ESH10000028.MUX_A

User-Accessible Channels

Total User Channels: 21 (10 MUX selectors + 1 BUSMUX + 8 cross-connects + 3 communication)

Channel Configuration

Multiplexer Channel Selection

Each MUX channel accepts a string value "0" through "7":

SetValues(
    new[] { "0.ESH10000028.MUX_A" },
    new[] { "3" }  // Select input channel 3 on MUX A
);

Bus Multiplexer Configuration

BUSMUX accepts the following destinations:

• None: No bus routing (default)
• I2C: Route I²C bus
• UART_ABEF: Route UART to MUX group A/B/E/F
• UART_CDGH: Route UART to MUX group C/D/G/H
• JTAG_ABEF: Route JTAG to MUX group A/B/E/F
• JTAG_CDGH: Route JTAG to MUX group C/D/G/H
• SPI_ABEF: Route SPI to MUX group A/B/E/F
• SPI_CDGH: Route SPI to MUX group C/D/G/H

SetValues(
    new[] { "0.ESH10000028.BUSMUX" },
    new[] { "I2C" }  // Enable I²C bus routing
);

Cross-Connect Switches

Digital cross-connect channels:

SetValues(
    new[] { "0.ESH10000028.AC" },
    new[] { "true" }  // Connect MUX A to MUX C
);

Programming Interface

Configure Multiplexer:

ConfigureChannels(new[] {
    new MultiplexerChannel {
        NetName = "0.ESH10000028.MUX_A",
        Enabled = true,
        Value = "5"  // Select channel 5
    }
});

Set Bus Routing:

SetValues(
    new[] { "0.ESH10000028.BUSMUX" },
    new[] { "UART_ABEF" }  // Route UART to ABEF group
);

I²C Communication:

// Perform I²C transaction on external I²C channel
SetValues(
    new[] { "0.ESH10000028.I2C" },
    new[] { "0x50:W:00,01,02" }  // Write to I²C device at 0x50
);

Best Practices

1. Set BUSMUX before communication: Configure bus routing before attempting I²C/UART/SPI/JTAG operations
2. Disable unused cross-connects: Minimize signal crosstalk by only enabling needed connections
3. Use MUX systematically: Plan signal routing to avoid conflicts
4. Check bus destination compatibility: Ensure ABEF/CDGH grouping matches your hardware connections

Module Initialization Sequence

On Reset(), the module performs:

1. Clear existing channel list
2. Create 10 multiplexer channels (MUX_A through MUX_K) with default "0"
3. Create BUSMUX channel with default "None"
4. Setup 4 GPIO expander chips for MUX control
5. Add 8 cross-connect digital channels (AC, BD, EG, FH, CE, DF, GJ, HK)
6. Add communication channels (I2C, UART, SPI)
7. Reset all GPIO expanders