Download Port Select; Resets; Serial Rom Chip Addresses - LSI Symbios SYM53C040 Technical Manual

Table 2.4

Serial ROM Chip Addresses

Serial ROM Chip Address
1010 000
1010 001
1010 010
1010 011
1010 100
1010 101
1010 110
1010 111

2.7.4 Download Port Select

2.8 Resets

As indicated in the table, the serial ROM chip address mapping is
equivalent to the power-on value of signal pins A[10:8].
AD10 Pull-up
None
None
None
None
Pull-up
Pull-up
Pull-up
Pull-up
The A11 pin selects which of the Two-Wire Serial interfaces will perform
the initial download. The default for the download is Two-Wire Serial
port 0. A pull-up resistor on the A11 pin starts the download from Two-
Wire Serial port 1, after a reset or at power-on.
The SYM53C040 can be reset in three different ways: power-on reset,
asserting the reset pin, and an internal chip reset forced by expiration of
the watchdog timer. A power-on reset initializes all chip registers to their
default values and returns the Two-Wire Serial port and the SCSI or
SFF-8067 interfaces to idle states. A power-on reset is caused when
power to the chip has been turned off and is turned back on. Manually
asserting the RESET/ pin triggers a soft reset. This can be done to
initiate a second configuration ROM download for the purpose of adding
more firmware or changing default register values before the chip begins
normal operation.
If the watchdog timer is used and it expires, it causes an internal soft
reset. If the Enable Reset Output bit is also set (0xFF05, bit 7), the
Resets
AD9 Pull-up AD8 Pull-up
None
None
Pull-up
Pull-up
None
None
Pull-up
Pull-up
None
Pull-up
None
Pull-up
None
Pull-up
None
Pull-up
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