lgta pull up

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lgta pull up

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plantowsky
Contributor I

We created a board with the MPC8349ECVVAJFB processor on it, but the signal

LGTA was not connected or pulled up.  Can we fix this by setting the LBCR( LPBSE ) bit to 1?

We will be using the GPCM with BR0 and OR0 to load flash at power up boot.  Currently

the board runs code then faults at the same address some times.  Below quoted from

MPC8349EA PowerQUICC II Pro Integrated Host Processor Family Reference Manual, Rev. 1.

"14 LPBSE Enables parity byte select on LGTA/LGPL4/LUPWAIT/LPBSE signal.

                  0 Parity byte select is disabled. LGTA/LGPL4/LUPWAIT/LPBSE signal is available for memory control as

                          LGPL4 (output) or LGTA/LUPWAIT (input).

                 1 Parity byte select is enabled. LGTA/LGPL4/LUPWAIT/LPBSE signal is dedicated as the parity byte select

                         output, and LGTA/LUPWAIT is disabled."

Roger Plantowsky

GET Engineering

rplantowsky@getntds.com

(619)443-8295

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2 Replies

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r8070z
NXP Employee
NXP Employee

Yes the GPCM ignores LGTA/ LPBSE pin state if the LBCR( LPBSE ) bit is set. But it fixes problem for sure only if you can set this bit before GPCM using. On reset this bit is cleared. The I2C boot sequencer can set this bit. Of course if the first instruction read from the boot flash set this bit the probability of the fail is decreased.

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plantowsky
Contributor I

Serguei,

Thanks for your comments.

The software group thinks that the BDI3000 debugger can set this

bit before the first instruction read.  Is this correct?

Roger Plantowsky

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