topic Lpc1769, stops answeing after write to LPC_EMAC->Command, have to use ISP to reset. in LPC Microcontrollers

Lpc1769, stops answeing after write to LPC_EMAC->Command, have to use ISP to reset.

lpcware — Wed, 15 Jun 2016 17:23:04 GMT

Content originally posted in LPCWare by baot on Thu Mar 19 08:23:29 MST 2015
Iam trying to use embeddedartist's easy web example.

in "ethmac.c" ->Init_EthMAC(void) they configure the mac with "LPC_EMAC->Command" if i remove that line the code runs fine, but ethernet dosent work for obvious reasons.
if i leave the code as is the system goes into some sort of "limbo-mode" and i have to use ISP to reset it..

iam using the code red tool chain and my phy is a lan8720, on a custom board, see attachment for code and schematic.

Re: Lpc1769, stops answeing after write to LPC_EMAC->Command, have to use ISP to reset.

lpcware — Wed, 15 Jun 2016 17:23:05 GMT

Content originally posted in LPCWare by R2D2 on Thu Mar 19 08:51:49 MST 2015
Could be useful to post your board / schematic as PDF :)

Did you compare them with LPCXpresso 1769 board?

Re: Lpc1769, stops answeing after write to LPC_EMAC->Command, have to use ISP to reset.

lpcware — Wed, 15 Jun 2016 17:23:06 GMT

Content originally posted in LPCWare by andersrosvall on Thu Mar 19 08:55:30 MST 2015
Hi,
Usually if the MCU hangs like you describe it is because of problem to communicate with the external PHY. That is where I would recommend you to start looking.
Kind Regards,
Anders @ EA

Re: Lpc1769, stops answeing after write to LPC_EMAC->Command, have to use ISP to reset.

lpcware — Wed, 15 Jun 2016 17:23:07 GMT

Content originally posted in LPCWare by MikeSimmonds on Thu Mar 19 10:36:33 MST 2015
We had an issue with LAN8270A (on a custom 1778 board)

Following Various EA and other schematics, we connected the chip reset out to the PHY reset (in) pin.
Sound reasonable yes.

BUT ...

The observed duration of the reset out pulse was on the order of 1 to 2 micro seconds; the 8270 data
sheet has a minumum reset duration of way way more than that (I can't remember the exact figure and
I am too lazy to find and open the datasheet). I was going to (and we actually did) re-route the PHY reset
to a GPIO to give me control of the PHY reset period.

On the current board, I just cut the track and that seened to do the trick. And I did not actually program
or use the GPIO pin on the re-spin.

One other thing, it may be better to set a break several steps after the failing line and let it run
through.

One last thing, we had an early problem with the 25MHz clock in to the PHY (bad capacitor), and
(there is a tiny note in the UM) if that clock is missing it will kill the debugger when setting up the EMAC.

Some of this may help, cheers Mike

Re: Lpc1769, stops answeing after write to LPC_EMAC->Command, have to use ISP to reset.

lpcware — Wed, 15 Jun 2016 17:23:07 GMT

Content originally posted in LPCWare by baot on Fri Mar 20 11:41:00 MST 2015

Quote: R2D2
Could be useful to post your board / schematic as PDF :)

Did you compare them with LPCXpresso 1769 board?

Yes, we did :)

Schematic is attached to this post.. it is missing some rc filters thoug and the reset on our barometer and some jtag pins are missing to. but for every air wire we have learnd something! :), and we havent tested the poe part yet..

Quote: andersrosvall
Hi,
Usually if the MCU hangs like you describe it is because of problem to communicate with the external PHY. That is where I would recommend you to start looking.
Kind Regards,
Anders @ EA

Quote: MikeSimmonds
We ....cheers Mike

We resolderd our phy and now it seems to be working, and thanks som much for the input!

Best regards baot and jeppe