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Re: [lwip-users] missing TX packets
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From: |
Pomeroy, Marty |
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Subject: |
Re: [lwip-users] missing TX packets |
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Date: |
Tue, 7 Jan 2014 14:27:37 -0500 |
* Don't run EMCCLK above 80MHz! *
On the datasheet for the LPC178x/7x, page 84 and 85 shows that
Tcy has a minimum of 12.5ns, which translates to a maximum EMC Clock of
80MHz. We found out the hard way that it may work on most LPC1788s, but
not on some! Not recommended to run it above spec.
Our product using LPC1788 has LCD at max refresh rate, AND
running the program itself out of DRAM, and no trouble with Ethernet. Not
sure where to look for issues... make sure everything is using 32 bit
transfers and DRAM is configured as a 32 bit interface...
I managed to fix the problem by increasing the EMC clock rate from
60Mhz to 104Mhz and lowering the refresh rate of the LCD. The LCD controller was
eating up all my bandwith to the external memory. Now both the webserver and the
LCD are working nicely.
Thanks for your help.