SPI puzzle

[ericgibbs]

hi,
I guess you know NSS is /CS .?? [NOT CS]

Where is the RESET connected.?

Are the DIO pins allowed to 'float' the datasheet should tell you.

As you say the PCB requires a 3.3v supply.

I usually add a 10k pull up on MISO

E


EDIT:
How are you planning to get the 18F2431 PIC to communicate via RS232 to the other PIC.????

 

[ericgibbs]

hi C,
This is a clip from my circuit showing the SPI and 74HC125 level shifter.

There are 100R's in series with the three PIC output pins to the HC125.
The logic +5v High input current should be limited to < 20mA when powering the HC125 with3.3v.
[I have sometimes used the HC without the 100R's with no problems, but I would not recommend this way]

Note the 10k pull up for MISO.

E

 

[camerart]

Hi Eric,
I think the SPI puzzle question has been answered, thanks. I'm moving back to the other thread: https://www.electro-tech-online.com...ion-receiving-using-scr-radio-modules.149198/

Cheers, C.