Board Configuration Registers - Adaptec AHA-1740A Technical Reference Manual

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Host ID 1 (HID1, zC81, R)
HID1 is the second byte of the expansion board ID. It is written by the local processor
and read by the system processor. RESDRV, HARDST or SOFTRST has no effect.
Bit Definition
7-5 Least significant three bits of the second compressed character of manufacturer's
ID. The most significant two bits are found in register HID0. The character is
always "D," which is represented by '00100'B.
4-0 Third compressed character of manufacturer's ID. Bit 6 is the most significant bit.
This character is always "P" which results in a compressed code of '10000'B.
Host ID 2 (HID2, zC82, R)
HID2 contains the adapter's product number. It is written by the local processor and
read by the system processor. RESDRV, HARDST or SOFTRST has no effect. Bit 7 is
the significant bit. The AHA-1740/1740A/1742A products number is 00h and the
AHA-1744 is 01h.
Host ID 3 (HID3, zC83, R)
HID3 contains the revision level of the firmware resident on the board. This is used
to identify the capabilities of the board to the manager and other software. The revi-
sion level may be changed during the firmware download process described in Chap-
ter Three, ADL Utility. It is written by the local processor and read by the system
processor. RESDRV, HARDST or SOFTRST has no effect. The revision code for the
AHA-1740/1744 is 00h, the AHA-1740A is 01h and the AHA-1742A is 02h.

Board Configuration Registers

These registers are used by the host process to define parameters on the board neces-
sary for normal operation. This function was normally provided by jumpers or on-
board DIP switches in ISA boards. These registers are accessible at any time.
Expansion Board Control Register (EBCTRL, zC84, W/R)
EBCTRL is used by the system software to control the host adapter hardware. Bit 2
is write only, 1 is read only and bit 0 is write/read.
Bit Definition
7-3 Unused. (0)
2 ERRST When this bit is set, HAERR and CDEN are reset to 0. (0)
1 HAERR When this bit is one, the host adapter has detected a serious error. Further
operation will produce unreliable results. This bit is set by the local processor. (0)
0 CDEN When this bit is cleared, the host adapter is held disabled. During this time
only expansion board registers can be accessed. (0)
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AHA-1740A/1742A/1744