Hot!Using MCP23017 on a MCP23X17 Evaluation Board, with I2C off-board

Author
BET64
New Member
  • Total Posts : 2
  • Reward points : 0
  • Joined: 2018/07/10 06:17:34
  • Location: 0
  • Status: offline
2018/07/12 03:16:46 (permalink)
0

Using MCP23017 on a MCP23X17 Evaluation Board, with I2C off-board

Hi,
 
I bought recently MCP23X17 Evaluation Board for test I2C interface with my Raspberry Pi Model B+ V1.2.
First, I started by checking that the evaluation board was operationnal : no issues (supply 5V on TP2, GND on TP1, all BP execute the default code to turn on/off the LEDs).
 
Secondly, I wanted to test my I2C interface with my Raspberry :
- 5V Supply on VDD (TP2) with EX355 Power Supply
- J1-1 (MCLR) on GND (to turn off the PIC)
- A0, A1, A2 on GND for Address 0x20
- SCL (Raspberry) on J4-2 (SCK)
- SDA (Raspberry) on J4-3 (MDSA)
 
When I execute "i2cdetect -y 1" via Raspberry, the I2C device is not getting detected.
What should I do then ?
 
Thanks in advance.
#1

2 Replies Related Threads

    qɥb
    Monolothic Member
    • Total Posts : 3329
    • Reward points : 0
    • Joined: 2017/09/09 05:07:30
    • Location: Jupiter
    • Status: offline
    Re: Using MCP23017 on a MCP23X17 Evaluation Board, with I2C off-board 2018/07/12 16:21:35 (permalink)
    +1 (1)
    You don't mention a ground connection between the Raspberry and the Eval board.
    Do NOT rely on the power supply connection to do it if you're using separate supplies for each board.
     

    This forum is mis-configured so it only works correctly if you access it via https protocol.
    The Microchip website links to it using http protocol. Will they ever catch on?
    PicForum "it just works"
    #2
    BET64
    New Member
    • Total Posts : 2
    • Reward points : 0
    • Joined: 2018/07/10 06:17:34
    • Location: 0
    • Status: offline
    Re: Using MCP23017 on a MCP23X17 Evaluation Board, with I2C off-board 2018/07/13 03:32:17 (permalink)
    0
    Hi qɥb,
     
    Even when connecting TP2/TP1 to the +5V and GND of the Raspberry (no separate supplies), it does not work. I also try to feed the card with +3V3, it does not work either. With the multimeter, I see that the MCP23017 is powered. The I2C bus of the Raspberry B+ V1.2 requires additional pull-up resistors?
    #3
    Jump to:
    © 2018 APG vNext Commercial Version 4.5