Possible to Use with Other HATs

[Mason]

Hi Forum 👋,

🤔 I am wondering if MCC118 Voltage Measurement DAQ HAT can be used with other HATs. In the github tutorial, it says that 'They are generally not compatible with any other brand of Raspberry Pi HAT or add-on board that attaches to the GPIO header, or devices that use the Raspberry Pi SPI interface.' However, I am trying to use Adafruit 16-Channel PWM / Servo HAT and MCC118 together.

😭 The only MCC118 or only PMW Hat can works well in my Raspberry Pi 4B. Unfortunately, they cannot work at the same time (PWM can still work but MCC118 cannot), and the errors display as shown in the atached pictures.

🧐 After analysizing the possible reason of conflicting, I find that the MCC 118 uses ID_SD and ID_SC (GPIO 0&1) in datasheet and PWM Hats only use these two pins (naming EECLK&EEDATA) in this link. I think that is the main reason that MCC cannot detect correctly.

😣 I am wondering is there a way to fix this conflict issue by using other pins or somethings. I appercaite anyone can share any thoughts and ideas on this matter, which will help me from struggling in a long time.

Thanks!

[Fausto]

Hello @Mason.

Your findings are correct.  According to the RPi 4B schematic (image from www.raspberrypi.org), the ID_SD and ID_SC pins are equivalent to the EEDATA and EECLK on the Adafruit PWM / Servo HAT, respectively.

 

You may try to set the MCC 118 as the first board on the RPi 4, but other than that, there is no workaround for other hats to be compatible with the MCC 118.

Regards,

Fausto

[Mason]

On 8/12/2024 at 9:20 AM, Fausto said:

Hello @Mason.

Your findings are correct.  According to the RPi 4B schematic (image from www.raspberrypi.org), the ID_SD and ID_SC pins are equivalent to the EEDATA and EECLK on the Adafruit PWM / Servo HAT, respectively.

 

You may try to set the MCC 118 as the first board on the RPi 4, but other than that, there is no workaround for other hats to be compatible with the MCC 118.

Regards,

Fausto

Hi Fausto,

Thank you for your reply and confirming.

Unfortunately, It does not work when I tried to stack MCC 118 as first board. 

Best,

Mason

[Nick Wright]

The address jumpers on the MCC hats will change the base address of the EEPROM on the ID bus.  You can set the MCC 118 to an address other than 0 and the EEPROM will no longer conflict with the EEPROM on the Adafruit hat.  I do not see any other signals that will conflict, so everything should work with that change.

Regards,

Nick

[Mason]

On 8/13/2024 at 3:17 PM, Nick Wright said:

The address jumpers on the MCC hats will change the base address of the EEPROM on the ID bus.  You can set the MCC 118 to an address other than 0 and the EEPROM will no longer conflict with the EEPROM on the Adafruit hat.  I do not see any other signals that will conflict, so everything should work with that change.

Regards,

Nick

HI Nick,

IT WORKS! Thank you for your clarification very much! 

I did not try to the address other than 0 because that the tutorial and github says that there must be address 0. It surprises me that the Adafruit Hat does have EEPROM (It does not mention in datasheet). There is one remaining point I still feel confused: 2 Adafruit hat are detect in the same address 0, but the MCC hats are detect as different address respectively. It makes no sense for me that two hats share same address.

Thank you!

Mason

[Fausto]

Hello @Mason.

I'm confused.  You have your RPi 4B stacked with two Adafruit 16-Channel PWM / Servo HATs followed by two MCC 118 HATs on top. 

10 hours ago, Mason said:

I did not try to the address other than 0 because that the tutorial and github says that there must be address 0.

If you didn't change the first MCC 118 HAT from address 0 and it appears that the 2nd MCC 118 (top HAT) has the address setting on the A1 jumper (address 2), then what changes did you make?

   

 

Regards,

Fausto

[Mason]

4 hours ago, Fausto said:

Hello @Mason.

I'm confused.  You have your RPi 4B stacked with two Adafruit 16-Channel PWM / Servo HATs followed by two MCC 118 HATs on top. 

If you didn't change the first MCC 118 HAT from address 0 and it appears that the 2nd MCC 118 (top HAT) has the address setting on the A1 jumper (address 2), then what changes did you make?

   

 

Regards,

Fausto

Hi Fausto,

Sorry for confusing. Your understanding is correct, I stacked two Adafruit Hats (Address 0) and follwed by two MCC118 (Address 1 & 2). 

I am wondering why two Adafruit Hats sharing with same Address 0.

Best,

Mason

Edited August 15 by Mason

[Fausto]

54 minutes ago, Mason said:

I am wondering why two Adafruit Hats sharing with same Address 0.

Good question for Adafruit Support.