No voltage on pin 65 (RB11)

Created Wed, 02 Jan 2013 15:58:25 +0000 by dgudorf

dgudorf

Wed, 02 Jan 2013 15:58:25 +0000

I'm using a ChipKIT Max32 and Network Shield to drive a pair of these panels for my university thesis project.

Whenever I attempt to use pin 65 (A11) via LATB, there is 0.00V on the pin, even though LATB is set to 0xFFFF and TRISB is set to all output.

Any suggestions?

majenko

Fri, 04 Jan 2013 13:48:06 +0000

From the manual:

The Ethernet MAC requires an external PHY to complete the implementation of an Ethernet network port. The Ethernet MAC constructs the digital format of packets being sent and performs the checking and buffering of packets being received. The PHY provides the physical interface and translates the digital signals used by the MAC into the analog voltages used on the Ethernet cable. There are two common interfaces used between an Ethernet MAC and the PHY: MII and RMII. The MAC in the PIC32 supports either interface, but the Max32 board is designed to use the RMII interface. The RMII Ethernet PHY interface uses the following pins: Pin 53 (EREFCLK), Pin 49 (EMDC), Pin 48 (EMDIO), Pin 47 (ETXEN), Pin 46 (ETXD0), 45 (ETXD1), Pin 43 (ECRSDV), Pin 42 (ERXD0), Pin 41 (ERXD1), Pin 40 (ERXERR), and Pin 7 (NRST).

Now, looking at the pin list, ERXERR is listed as pin 28, RG15. However, according to the schematic, ERXERR is in fact pin RB11 (with B12 and B13 being ERXD0 and ERXD1).

So, if the schematic is correct (which you'd hope it was), then you can expect to not be able to use those three analogue pins. If the ethernet module is enabled, then the other functionality of those pins will be disabled.

Vittorio

Mon, 07 Jan 2013 12:26:56 +0000

Hi, I have a similar problem I'm using the pin A1 ... A16 as a digital input and i cannot read the three pins A11, A12 and A13.

I'm not using the ethernet shield and i have not enabled an ethernet communication explicitly.

I am using the SPI (SD.h) and two software SPI. does the sd library create any interference?

could be the case that there is a default setting activating the ethernet?

thanks for any hint.

Vittorio

Wed, 09 Jan 2013 10:42:18 +0000

I solved my problem... i didnt consider that A11, A12 and A13 share the same cpu pin with other board pins.