RE: [linuxsh-dev] SH4 hardware problem

[Dustin M. <du...@se...>]

Hi Mark,
I don't know about the SH7750, but the SH7751 has a RDY# pin that forces the
processor to stall indefinately waiting for the bus cycle to complete.  You
may want to check this and make sure it is not asserted (ie make sure it is
logic high).  There should be and external pullup resistor on this pin as
well.

Dustin.

-----Original Message-----
From: lin...@li...
[mailto:lin...@li...]On Behalf Of Barkuson
Sent: Wednesday, July 04, 2001 6:43 AM
To: lin...@m1...; lin...@li...
Subject: [linuxsh-dev] SH4 hardware problem



Hi,

Firstly, my apologies for sending this mail if this is
not relevent to the mailing list. However, this is
quite urgent, sorry. Could any hardware people help me
out please?

I have a custom Sh4 (SH7750) board which has not been
able to run :(. Everything looks alright except that
the board boots up and sits at address 0x00000000 (the
data at this address in the flash memory is on the
data bus). The CPU seems to halt at this point with
the following board status,

- both main crystal and rtc crystal running
- both status pin at low level
- all NMI and IRL pins pulled up
- BREQ pulled up
- address sits at 0x00000000 and does not increments
- CS0 low
- RD low
- all WE high

Is there anything else that I should check?? or any
setting that I could be missing??

Can anyone direct me to a right place??

All helps are greatly appreciated.

Mark


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