S32K148-Q176 EVB rev.B and lwIP demo

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S32K148-Q176 EVB rev.B and lwIP demo

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janijärvenpää
Contributor II

Hi, I am trying to connect TI DP83848 ethernet phy to evaluation board using RMII.  I am using lwIP demo to test that the hardware is working so i can work on the PCB.

S32 SDK says:

S32 SDK: lwIP TCP/IP stack

The following boards are supported by this application:

S32K148EVB-Q100

I am using 176 pin version. What would be the difference? Pinout?

Do i need to make modifications to the evaluation board?

Thanks,

Jani

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janijärvenpää
Contributor II

Tested with enet loopback demo, and started seeing signal at TX pins.  Something wrong with the phy though, its only transmitting 1.2V RX signals, and they are not getting through level shifter.

These cheap module boards are pretty bad and wiring 50Mhz signals with dupont wires is not the best idea either, getting so much noise...

I am feeling cofinent enough, going make the PCB. :smileyhappy:

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janijärvenpää
Contributor II

Looked up the datasheet, RX signals were open drain/pull down type, connected 6k8 pullup resistors between RX's and 3v3, and now i can send and receive frames! Using enet loopback demo.

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jiri_kral
NXP Employee
NXP Employee

Hi Jani, 

the pins - in meaning pin names - are same for Ethernet across all package layouts: 

Example itself is tested with TJA1100 Ethernet phy. You need to change package layout in project to 176 pins:

https://community.nxp.com/docs/DOC-334936 

pastedImage_3.png

Hope it helps. 

Jiri 

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janijärvenpää
Contributor II

Hi, I cannot get this to work.

I am using ethernet board with schematic like this:

https://www.waveshare.com/w/upload/3/31/DP83848-Ethernet-Board-Schematic.pdf 

I made breakout board for the QTH connector J16, and connected the board with dupont wires.

Connections seem to be OK, checked everything with multimeter, nothing shorted or unconnected.

I have RMII wired like this:

phy pin-mcu pin, pin in evb J16

-------------------------

TXD0-PTC2, PIN 14

TXD1-PTD7, PIN 16

TXEN-PTD12, PIN 24

OSCIN/X1-PTD11, PIN 20

CRSDV-PTC17, PIN 28

RX0-PTC1, PIN 36

RX1-PTC0, PIN 38

MDIO-PTB4,PIN 48

MDC-PTB5, PIN 50

Note, Receive error not connected

I am using LwIP example with prosessor changed to 176 pin version. Code is running just fine.

When i tested with oscilloscope, i saw <1V signal in TX0 and TX1 pins at MCU. Why does it not get to 5V?

I looked reference manual and it says on page 1845:

Enable the Drive strength for the transmitting pads of ENET by setting DSE field of PORT_PCRn register

LwIP example does not seem to do that.  I tried to modify the generated pin mux to  do that:

pastedImage_2.png

TX Signals still not getting pulled to 5V.

Can anyone help?

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