I2C-RPT-08

Features

• I2C Hub / Repeater / Replicator / Multiplexer / De-multiplexer / Switch
  • PCA9548A Datasheet
  • Eight I2C Ports
  • 100KHz/400KHz operation
  • I2C Base Address 0x70
    • Offset addresses 0x70-0x77
• Host port
  • Controlled via I2C
  • 3.3V or 5V host operation
  • Can power slave cards if they are at the same voltage
• 3.3V or 5V slave ports operation
  • Removable jumper(s) to supply power from slave
• Voltage translation between the ports
  • Ex: a Raspberry Pi which runs 3.3V can control I2C devices which run at 5V
• On-board 2.2K termination resistors
• 49x49mm form factor
• 4 solid 4-40 mounting holes
• Drivers/Example Code
  • Arduino driver and example code
  • Raspberry Pi example code

Connectors

• 0.1" pitch connections
• Search ebay for Dupont headers
• Search ebay for Dupontwire jumper cable
• The slave I2C connectors are (4) 2x6 right angle 0.1" pitch headers
• Two ports per 2x6 connector
• Two of the pins are for power to or from the I2C connector
• The other four pins are for the I2C interface

H1-H8 - Power to/from I2C Connectors

• Install shunt to power the I2C slave card from the I2C-RPT-08 Card
  • Default factory ships as installed to power external I2C interfaces from the card
• Remove shunt to power interface externally
  • Need to remove if external voltage is different level or sourced externally
• H1 - PORT #0
• ...
• H8 = PORT #7

H9 - I2C Slave Address Jumpers

• A0-A2
• Install all 3 jumpers for address 0x70
• Remove all three jumpers for address 0x77

J1 - Host I2C Connection

1. GND (GND pin marked)
2. 3.3V or 5V VCC
3. SDA
4. SCL

J2-J5 - Slave I2C Connections (x8)

1. GND
2. 3.3V or 5V VCC (Power Out - if jumper 1-2 installed, Power in - if jumper 1-2 is not installed)
3. SDA
4. SCL (Board marked with SCK)

Jumpers

A0-A2 - Multiplexer I2C Base Address

• Install for Ax = 0 (factory default address = 0)
• Remove for Ax = 1

Schematic

• I2C-RPT-08 Schematic

Drivers/Example Code

• Github repo - Driver code
• Github repo - Example code

Programming Note

• The mux chip allows multiple or single I2C ports to be written at the same time
  • To only enable one port at a time make sure you disable a channel after use or disable last channel used before enabling new channel

Testing

Test Station Hardware

• Arduino Based Test Station
  • Built in I2C mux on BLACK-PILL-HUB is set to offset=0x1 so it does not conflict with I2C address of UUT

• Uses 8x of I2CIO-8 cards
• On UUT
  • Install jumpers into A0-A2
    • I2C address offset = 0x0
    • BLUE-PILL-HUB is set to offset=0x1 so it does not conflict
• Connect directly to I2C port on the BLUE-PILL-HUB
• ODAS Tester Github Repo

Test Procedure

• Run puTTY
  • COM port from Device Manager
  • 9600 baud
  • No parity
  • No handshake
• Menu will display

Checking if EEPROM is present on UUT...EEPROM is not present on UUT
Count of I2C devices in range 0x20-0x27 on UUT = 0
Found external I2C mux card
Select I2C Mux board type
1 - I2C-RPT-01 board
2 - I2C-RPT-08 board

• Enter 2
• Replies with

Init I2C-RPT-01 card
I2CIO8 card #0 was detected
I2CIO8 card #1 was detected
I2CIO8 card #2 was detected
I2CIO8 card #3 was detected
C=Card Tests, D=Direct, E=EEPROM, I=access Internal DIGIO32

Rev 1 Issues

• Silkscreen shows SCK, should be SCL

Assembly Sheet

• I2C-RPT-08 Assembly Sheet