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GT-64260B Reset Configuration
The GT-64260B supports two methods of device initialization following
reset:
The MVME5500 board supports both options listed above. An on-board
jumper setting is used to select the option. If the pin-sample-only method
is selected, then states of the various pins on the device AD bus are
sampled when reset is deasserted to determine the desired operating
modes.
Combinations of pullups, pulldowns, and jumpers are used to set the
options. Some options are fixed and some are selectable at build time by
installing the proper pullup/pulldown resistor. Finally, some options may
be selected using on-board jumpers.
Using the SROM initialization method, any of the GT-64260B internal
registers or other system components (that is, devices on the PCI bus) can
be initialized. Initialization takes place by sequentially reading 8-byte
address/data pairs from the SROM and writing the 32-bit data to the
decoded 32-bit address until the last serial data item of 0xffffffff is read. If
the SROM initialization option is selected, the following pins are still
sampled to determine certain operating parameters:
http://www.motorola.com/computer/literature
Pins sampled on the deassertion of reset
Partial pin sample on deassertion of reset plus serial ROM
initialization via the I2C bus
Table 2-5 on page 2-10
AD(1) – SROM byte offset width
AD(3:2) – SROM address
AD(4) – CPU endianess
GT-64260B Reset Configuration
describes the configuration options.
2
2-9
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