i_r_on wrote:
I just bought a bunch of cheap 65C816 processors from China. I want to test them before I confirm the transaction if they are dodgy/broken or not. (They are Winbond made labeled W65C816S8P-14)
Winbond-made? I wasn't aware that they were ever licensed to produce the 65C816 as a discrete device. If they were, the part number
definitely would not be
W65C816S anything, as that is the genuine WDC part number (the
8P part refers to the geometry and packaging, and the
-14 is the speed rating). I'm suspecting that you may have counterfeits.
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The question is : Is there anything else I need to care to do the NOP test on the 65C816 different from the same test that can be done on 6502?
Short of running these devices in a 65C816 system that is known to correctly operate, I doubt that you can devise a test regiment that will 100 percent prove that you have fully functional hardware.
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- 1Mhz Oscillator Can connected to PHI0 IN
There is no
PHI0 IN input on a 65C816. Also, you need to be running a much higher Ø2 frequency to fully qualify the part.
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- RDY, IRQ, NMI, ABORT pulled high by 10k resistors.
Make that 3.3K resistors and don't forget
BE, which must be high in order for the MPU to be able to drive the buses.
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- RESET connected to a tactile button, open position is pulled high with 10k Resistor, when shorted connects it to the GND.
A push button alone will not generate a clean reset, due to contact bounce. You may be able to get away with a simple R-C delay circuit that dampens the bounce. An alternative is to use a Maxim DS1813 reset generator.
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- D0..D7 pulled high or low with 10K resistors to make the NOP opcode (EA). 11101010 (1=pull up, 0=pull down)
Again, make that 3.3K resistors.
Quote:
- A0..A7 directly connected to logic analyzer.
Presumably you are just monitoring the address lines. Make sure that they are all clearly in logic zero or logic one voltage ranges at all times.
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The first chip I tested put continuous DA on A7..A0. The others made some other weird things
Now I'm unsure whether my test fixture is bad or actually the chips are bad. Any idea?
Make sure
BE is pulled high and then test again. As I said above, I think you may have been sold counterfeits.