prom question

coinopjunkie

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Okay so I'm still trying to find out about the nintendo security prom. Everyone says they are suppose to be RP5H01's but I'm told they are 64 bits and the files in mame for this chip are 128 bit's? So how could these chips be RP5H01's?
 
The datasheet says there is a 7 bit counter. 7 bits is 128. Beyond the 64 bits are 8 'test bits' that can be written. But there's nothing to stop one from reading the whole 128 bits.
 
Normal Nintendo boardsets like DK3 boards use RP2A03H CPU chips. Proms have 16 legs and are like 82S123 or 82S129 which can only be programmed once and they contain info like color addressing code.
 
thanks

Normal Nintendo boardsets like DK3 boards use RP2A03H CPU chips. Proms have 16 legs and are like 82S123 or 82S129 which can only be programmed once and they contain info like color addressing code.

Proms can have many different amount of legs, I know the 8 leg chips I have are proms I just don't know how we know these are what Nintendo used? Also about why the different size file compared to the chip size.
 
response from engineer

You are talking about the 'Test Byte', I already knew about that, it only accounts for 1 more byte.

It only allows you to address 1 extra byte for testing and the Test pin must be pulled Hi.
 
Like I said, a 7-bit counter is used for addressing. Which means you can address 128 bits. It doesn't mean all those extra bits contain anything meaningful, but it's totally possible for the Playchoice to read them. The datasheet doesn't define what is there.
 
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