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Download PX1 User Manual - Blue Chip Technology
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PAGE 22 HARDWARE DESCRIPTION PX1 USER MANUAL BUS CONNECTORS The board incorporates the standard PC/AT 16-bit ISA bus, and PCI bus connectors to passive backplanes. Additionally, the board has one set of PC104/AT sockets for on-board expansion. See the appendices for the pinout details. Note that the PCI connector details the signals at the PX1 processor connector. These are different for each PCI slot on a backplane. JUMPERS Jumpers are used on the board to select various options. Some of the jumpers are factory set to suit particular semiconductor options. These must not be disturbed, or damage to the board may ensue. Refer to the board layout drawing at the end of the manual for the positions of the various jumpers. CPU FREQUENCY SELECTION J1 & J11 The external CPU bus operates at frequencies of 50, 60 and 66 MHz but is scaled up internally giving a range of CPU frequencies of 75 to 166 MHz. There are four links ( in two locations) involved in CPU frequency selection: J1 and J11. Link J11 selects the host CPU operating frequency of 50, 60 and 66 MHz. Link J1 selects the clock scaling (multiplying) factor. Link J1 is latched by the CPU on reset and used to configure the CPU phase locked loop oscillator. This allows higher speed processors to be clocked down (e.g. running a P133 as a P100), but over clocking processors is not recommended as it will degrade the reliability of the device over time. Note also that there are internal differences between each of the CPU types, i.e. there are register differences between a P100 and a P133, it is not simply silicon grading as was the case for 486 type CPUs. INTERNAL CPU CLOCK SPEED J1 These jumpers sets the internal CPU clock speed to either 1½, 2, 2½ or 3 times that of the external CPU clock speed. These jumpers should be configured depending on the speed of the processor. 01271019.doc Blue Chip Technology Ltd.
