关于NSF的nmi信号问题

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fogota
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关于NSF的nmi信号问题

Post by fogota »

有一个关于NSF的重大问题:
NSF播放器没有PPU,那么NSF播放器有没有60Hz的NMI信号呢?
那么有没有irq的信号来呢?
nsf播放器是怎样的硬件电路图呢?有谁知道?
lidnariq
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Joined: Sun Apr 13, 2008 11:12 am

Re: 关于NSF的nmi信号问题

Post by lidnariq »

http://kevtris.org/Projects/hardnes/ ? http://www.elektroda.pl/rtvforum/topic3108894.html ? https://sites.google.com/site/nyanfc/ ?

The exact time source or interrupt source for the NSF is not specified; a hardware implementation could use a Programmable Interval Timer such as the 8254 hooked up to either input.
(google: 未指定NSF的确切时间源或中断源; 硬件实现可以使用可编程间隔定时器,例如8254连接到任一输入。)
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aquasnake
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Re: 关于NSF的nmi信号问题

Post by aquasnake »

他用两级74反向器和一些电阻电容实现了50Hz发生器代替了PPU的NMI输出给到cpu

当然,网络上有很多74门实现的 50/60Hz发生器,这很容易制作.由于只是CPU驱动播放NSF,并不涉及到精确的通讯传输,因此50/60Hz时钟的精度并不要求很高.

He implemented a 50Hz generator using two-stage 74 inverters and some resistors and capacitors to replace the NMI output to the CPU.
Of course, there are many 50/60Hz generators implemented through 74 gates on the network, which is easy to DIY.Due to only playing NSF on the CPU and not involving precise communication, the accuracy of the 50/60Hz clock is not required to be a high degree
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