27C801 Programming Help Needed

[astaroth]

Hi,

You seem like a knowledgable bunch so thought this would be the best place to ask for a little help!

I bought a PCB3 Willem Programmer in order to program a ...... program onto a 27C801 EPROM.

All programmed ok but the verify threw up an error.

I used a BIN checker to check it against the original BIN and it came up with 2 differences, 3 bytes. The first error was 2 bytes and the second 1 byte.

I then used an emulator to check the programmed BIN and it ran ok for the first 5 minutes play.

Am i right in assuming that these differences with mess up the game later in proceedings? The error was ay 0x0FF555, near the end of the code?

Am i also right in assuming that i need to UV the EPROM and try again?

Thanks in advance for any help.

[poppo]

I then used an emulator to check the programmed BIN and it ran ok for the first 5 minutes play.

Am i right in assuming that these differences with mess up the game later in proceedings? The error was ay 0x0FF555, near the end of the code?

Am i also right in assuming that i need to UV the EPROM and try again?

Yes if the code was not burned right, 'something' will eventually not work right.

You can try burning the same chip again without erasing it first. I've done that when it fails a verify on a 'stubborn' chip. Sometimes I've had to do it a few times. Since bits that are 'flipped' already don't need to be flipped again, it should only try to program the bits that failed the first time. Unless the chip was not completely empty first. I always do a blank check before programming.

[astaroth]

I then used an emulator to check the programmed BIN and it ran ok for the first 5 minutes play.

Am i right in assuming that these differences with mess up the game later in proceedings? The error was ay 0x0FF555, near the end of the code?

Am i also right in assuming that i need to UV the EPROM and try again?

Yes if the code was not burned right, 'something' will eventually not work right.

You can try burning the same chip again without erasing it first. I've done that when it fails a verify on a 'stubborn' chip. Sometimes I've had to do it a few times. Since bits that are 'flipped' already don't need to be flipped again, it should only try to program the bits that failed the first time. Unless the chip was not completely empty first. I always do a blank check before programming.

Thank you for such a quick reply! I'll give what you have advised a go tomorrow as it's too late in the day to do it now.

I'll post up my results tomorrow.

Again, thanks for your help poppo!

[astaroth]

I tried what you said but it errored again. And when i compared the BINs this time i had 156 differences! 

Going to UV the EPROM and try from scratch again.

[poppo]

And when i compared the BINs this time i had 156 differences!  

Now that is odd. You should not have been getting more differences. Worse case they should have stayed the same. Do you have all jumpers set properly for that 27C801? On my model one needs to be removed for that chip.

[astaroth]

And when i compared the BINs this time i had 156 differences!  

Now that is odd. You should not have been getting more differences. Worse case they should have stayed the same. Do you have all jumpers set properly for that 27C801? On my model one needs to be removed for that chip.

I thought it odd too! I UV'd the chip and re-programmed it and it verified ok this time round! Therefore i won't question my Willems cheapness and decision to throw odd stuff at me! 

Thanks again for taking the time to help poppo. Appreciate it. Think i'll stick around here for a bit and see if there's anything that catches my eye!