Hardware Preparation
2-5
2
IP Bus Clock Header (J11)J11 selects the speed of the IP bus clock. You can either set the IP bus
clock to 8MHz or allow it to match the the local bus clock, which is
32MHz for the MC68040. The factory configuration has a jumper
between J11 pins 1 and 2 for an 8MHz clock.
If the jumper is installed between J11 pins 2 and 3, the IP bus clock
speed is the same as that of the MC68040 bus clock, that is 32MHz,
allowing the IP module to run with a 32MHz MPU. Regardless of
the IP bus clock setting, all IP ports operate at the same speed.
!
Caution
The IP32 CSR bit (IP2 chip, register at offset $1D, bit 0)
must be set to correspond to the jumper setting. This is
cleared (0) for 8MHz, or set (1) for 32MHz. If the jumper
and the bit are not configured the same, the board may
not run properly.
(Factory configuration)
8MHz IP Bus Clock 32MHz IP Bus Clock
(from MPU Bus Clock)
J11
J11
123 123