PMC557 Switches SW1, SW2, SW3 Description


The PMC557 switch positions are defined in the following table:

Switch

Switch Position

Setting

Description

SW1

1

On

Used for hardware and firmware development purposes only.  Do not modify.

SW1

1

Off

Used for hardware and firmware development purposes only.  Do not modify.

SW1

2

On

Used for hardware and firmware development purposes only.  Do not modify.

SW1

2

Off

Used for hardware and firmware development purposes only.  Do not modify.

SW1

3

On

The host will be forced to retry any PCI access as long as firmware has not started. This allows to make sure that the PMC557 firmware has setup the configuration registers properly. A board without working firmware will cause the host to retry accessing the board forever!

SW1

3

Off

Disable forced PCI access retries.

SW1

4

On

The PMC557 embedded CPU will start after power up.  This switch is used for development purposes only.  Do not modify.

SW1

4

Off

The PMC557 embedded CPU will be held in RESET after power up.  This switch is used for development purposes only.  Do not modify.

SW2

All

On

This switch controls the timing and memory layout of the FLASH devices. It must not be changed since these values would make it impossible for the firmware to access the FLASH.

SW3

1

On

Enables write protect. When set on this will disable the write of data to the FLASH. That means that the firmware even cannot detect the FLASH IDs!

SW3

1

Off

Disables write protect.