hi,
Office 2010 Pro Plus Key,
we are interfacing coldfire mcf5232 processor having a fpga. processor accesses fpga registers utilizing standard go through write cycles (without burst).
these read/write cycles are terminating primarily based on transnfer acknowledge signal. fpga is producing this signal when it can be ready to write/ go through the knowledge.
we could read/write information when processor system clock is configured to 75mhz and 100 mhz. but it is not working when processor system clock is 150mhz.
we followed below mentioned steps to debug this issue.
step1 :
checked fpga input clock,
Cheap Windows 7, processor clkout frequency on board. – all are correct.
processor clock clkout frequency
75mhz 37.5mhz
100mhz 50.0mhz
150mhz 75.0mhz
step2 :
we checked processor cycles termination register configuration to external termination is set. cscr5.8 (aa - auto acknowledge enable is 0)
step3 :
we configure system clock to 75mhz, we could write and read information in fpga registers. processor write cycle is terminating after sampling “transfer acknowledge” signal. – as expected
step4 :
we configure system clock to 100mhz,
microsoft Office 2010 License, we could create and go through info in fpga registers. processor write cycle is terminating after sampling “transfer acknowledge” signal. – as expected
step5 :
we configure system clock to 150mhz,
Windows 7 Activation, we saw in fpga integrated logic analyzer,
Windows 7 Home Premium Product Key, processor chip select is going high before “transfer acknowledge” signal changing to low. can you please advise us why processor chip select is going high (termination of cycle) before sampling “transfer acknowledge” low.
step6 :
to check above misbehavior we tied fpga “transfer acknowledge” signal to permanently high and checked processor chip select behavior in integrated logic analyzer during processor compose cycle .
for 75mhz and 100 mhz - we saw chip select signal is continuously low and not going high for 29 cycles.
for 150 mhz - even though transfer acknowledge signal is permanently high. chip select signal is going low and after 4 cycles it really is going high.
thanks in advance.