User`s manual

Am486
®
Microprocessor PCI Customer Development Platform
2-35
Resistor Options
The PCI CDP includes a number of resistor populate/depopulate options, which
are listed in Table 2-11. Many are used only as manufacturing options, but some
may be useful for exploring design options or better emulating a target design.
Table 2-11. Resistor Options
Part Signal Description Location in
Figure 2-3
on Page 2-5
See App. B
Schematics
on:
R11 CLKMUL When R11 is populated and R148 is
removed, the clock multiplier for an
Am486DX2-66 microprocessor is
selected.
M17 Sheet 2
R58 ENRTC When populated (the default), the
M1487 chip’s internal RTC is disabled
and the DS1685 Y2K-compliant RTC
is enabled.
I14 (back
side)
Sheet 16
R59 CMPSTJ When removed (the default), the 1X
CPU-to-PCI bus frequency multiplier
is selected. (1X is the only multiplier
supported in this design.)
I14 (back
side)
Sheet 16
R70 TURBO When R70 is removed and R71 is
populated (the default), the M1487’s
TURBO signal is High (asserted). This
input must be enabled by software to
have any effect.
I14 (back
side)
Sheet 17
R71 TURBO When R71 is populated and R70 is
removed (the default), the M1487’s
TURBO signal is asserted. This input
must be enabled by software to have
any effect.
I14 (back
side)
Sheet 17
R93 CLKPU2 When R93 is populated and R176 is
removed, the system clock speed is 25
MHz.
J3 (back
side)
Sheet 18