blog:286_shootout_vlsi_vl82c311l

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blog:286_shootout_vlsi_vl82c311l [2021/04/23 13:43] – [Further Testing] johnblog:286_shootout_vlsi_vl82c311l [2021/04/23 14:09] (current) – [Further Testing] john
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 ==== Further Testing ==== ==== Further Testing ====
 +
 +=== Clock Signals ===
  
 The 14MHz oscillator which was still fitted to the board on receiving it is working; the clock is present on the output pin from the can as well as on ISA socket pin B30 (//OSC//): The 14MHz oscillator which was still fitted to the board on receiving it is working; the clock is present on the output pin from the can as well as on ISA socket pin B30 (//OSC//):
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 {{:blog:286:20210423_134011.png?600|}} {{:blog:286:20210423_134011.png?600|}}
 +
 +Processor pin 31 (//CLK//) has a 9.996MHz clock:
 +
 +{{:blog:286:20210423_135456.png?600|}}
 +
 +//This doesn't seem correct//. The processor is a 20MHz unit, and is being driven, as is normal on a 286, by a standard DIL can oscillator of 2x the processor frequency (i.e. 40MHz). The definition for pin 31 is that it //"is divided by 2 internally within the processor to generate the processor clock"// (from the {{ :blog:286:amd_80286_datasheet_june_1989_.pdf|AMD 80286 datasheet}})... that would mean the processor is only at 5MHz. Unless I misunderstand the datasheet, something is drastically wrong here.
 ===== Configuration ===== ===== Configuration =====
  
  • blog/286_shootout_vlsi_vl82c311l.1619181783.txt.gz
  • Last modified: 2021/04/23 13:43
  • by john