Multiple Slaves

[Multiple Slaves]

Hello All, I am trying to run my screen and SD card at the same time. Strangely, the moment I attach the miso pin of the SD card the screen will stop working.

Also, both slaves are on different pins for their chip selection, 10 for the screen and 5 for the SD card, respectively.

Any help would be really appreciated.

Thank you!

[lightcalamar]

Do you use HotMCU screen or another?

Possible photo of your assembly?

[Multiple Slaves]

I am using a Riverdi 800 x 600 screen. Unfortunately I do not have a photo of the assembly as it has been dismantled until a solution is determined. Essentially I am using the Sparkfun CC3000 wifi shield which has an SD Card compatibility with it.

The Arduino Mega is the master unit for my setup.

For the Sparkfun CC3000 Wifi Shield:

I attach this devices chip select to pin 4 of the Mega.

Sparkfun CC3000 Wifi Shield MISO is Attached to the respective MISO spot on the six pronged SPI unit on the mega

Sparkfun CC3000 Wifi Shield MOSI is Attached to the respective MOSI spot on the six pronged SPI unit on the mega
Sparkfun CC3000 Wifi Shield SCLK is Attached to the respective SCLK spot on the six pronged SPI unit on the mega
Sparkfun CC3000 Wifi Shield VCC is Attached to the respective VCC spot on the six pronged SPI unit on the mega
Sparkfun CC3000 Wifi Shield GND is Attached to the respective GND spot on the six pronged SPI unit on the mega

5 V and ground are attached to the required supplies.

For the Riverdi Display:

The Riverdi Display's ribbon cable is attached to the Riverdi shield which converts the ribbon cable to pins.

Using the Riverdi Shield.

GND is connected GND
BLVDD is connected to 5 V
VDD is connected to 3.3V

MISO is connected to pin 50 on the Mega and run through a bidirectional converter converting the voltage from 5 V to 3.3 V (This has also been tried using a simple voltage divider)

MOSI is connected to pin 51 on the Mega and run through a bidirectional converter converting the voltage from 5 V to 3.3 V (This has also been tried using a simple voltage divider)

SCK is connected to pin 52 on the Mega and run through a bidirectional converter converting the voltage from 5 V to 3.3 V (This has also been tried using a simple voltage divider)

CS is connected to pin 10 on the mega after being run through the bidirectional converter or using a voltage divider.

The SD reader has been tested and works properly using the included Arduino SD Library and the Riverdi Display functions on it's own.

The problem is the moment both MISO pins are in the other slave will stop working

Thank you for your help

Regards,

MultipleSlaves

[MultipleSlaves]

UPDATE:

The situation was remedied by using a 4 GB Kingston SD Card instead of my 2 GB one

Thank you!

[jamesbowman]

See this thread.

gameduino2.proboards.com/thread/71/using-sd-card-data-storage

The issue is that the GD library does not release the CS signal between API calls. This is for performance. The solution is to use GD.__end() and GD.resume() calls to force the GD library to release.

[MultipleSlaves]

Jun 6, 2017 8:06:49 GMT -8 jamesbowman said:

See this thread.

gameduino2.proboards.com/thread/71/using-sd-card-data-storage

The issue is that the GD library does not release the CS signal between API calls. This is for performance. The solution is to use GD.__end() and GD.resume() calls to force the GD library to release.

Thank you Kindly Jamesbowman,

I appreciate all your hard work!