7I90HD 3
HARDWARE CONFIGURATION
FPGA FLASH SELECT
To make recovery from FPGA configuration errors easier, there are two FPGA
configuration flash memories on the 7I90HD card. Jumper W3 selects between the two
flash memories. That is, if one flash memory is inadvertently corrupted, the other one can
be used to boot the 7I90HD, allowing the corrupted flash memory to be re-written. It is
suggested that W3 be left in the UP position (primary flash memory) for normal operation,
and only changed to the DOWN position (secondary flash memory) if configuration fails.
Once rebooted via a power cycle, jumper W3 should be promptly restored to the UP
position to allow the primary flash memory to be re-written.
W3
MEMORY
UP
PRIMARY (NORMAL OPERATION)
DOWN
SECONDARY (BACKUP)
SECONDARY FLASH WRITE ENABLE
To prevent accidentally overwriting the secondary FPGA configuration, a jumper
must be installed on jumper block W4 to enable writing to the secondary flash chip. When
W4 is not present, the secondary flash is read-only.
RS-422 CABLE POWER
The 7I90HD can supply or source 5V power from its RS-422 connector J1 if desired.
If cable power is selected, the 7I90 can be powered via a CAT5 interface cable. Cable
power is compatible with Mesa serial daughtercards. W5 controls the cable power option.
When W5 is in the up position, 5V power can be sourced or supplied by J1 pins 7 and 8.
When W5 is in the down position, J1 pins 7 and 8 are unconnected.
