neese@adaptx1.UUCP (05/22/91)
>>Your terminator scheme should be as follows: >>If you have a device on the external connector of the 1542 and add a device >>to the internal connector, do the following: >>Remove the terminators from the 1542. Make sure the last device on the >>external connector of the SCSI bus has terminators. Make sure the last >>device on the internal connector of the SCSI bus also has terminators. > >I have a 1542a controller to which i have an (internal) wrenIV hooked >up. I wish to add another one or two drives but they must be connected >externally (no more room in the case (:-(). The AHA-1540A/1542A user's >manual [(c) 1989] that i have for the 1542a states on page 3-2 that i >must remove the terminators at locations RN3, RN4, and RN5. The terminator resistors for the 1542A are located at RN3, RN4, and RN5. The 1542A is a surface mount full length board. The only removeable parts are the BIOS, firmware, and the resistor terminator packs. >Unfortunately for me, my board (ANNIE II, ASSY 416006-00 rev 3e >[originally 3a], BIOS 420403-00 2A @ 1988) doesn't appear to match the >documentation (actually, it is probably the reverse). The only >removable resistor packs (DIP) are in the upper right corner and are >labled RN2 and RN4. The other resistor packs are the long skinny kind >with 8 or 10 pins and look like a tiny comb. They are soldered directly >to the board and are labeled RN1, RN3, RN5, and RN6. They are scattered >at various locations all over the board (RN1 by J1, RN3 by J4, RN5 and >RN6 by the BIOS). Are the terminators for this board really the two >removable resistor DIPS RN2 and RN4? If so, why did the board change >the number of packs from 3 to 2 or from 2 to 3 (depending on which came >first; my documentation or my board)? Sounds like the 1540 adapter. This adapter is a TTL based adapters with only one surface mount part (AIC-6250). The DIPS's are the terminator packs for this adapter. It changed from 2 DIPs to 3 SIPs. The original adapter just did not have the room for the more common SIPs. >One more question. The wren IV is capable of sync operation while the >wren III is not. Would it help or hinder to enable the sync negotiation >jumper on the 1542? I'm guessing that is should not be a problem for >the wren III, right? The "OEM" manual for the wren IV doesn't mention >any way of enabling the sync option on the drive except via software. >If the 1542 has sync negotiation enabled via the jumper, will it be able >to initiate sync operation with the wren IV or will this command have to >come from the driver (in my case Esix 5.3.2-D)? Also, what kind of >speed/throughput can i expect from sync vs. async operation on this >drive (and/or in general)? Installing the sync negotiation jumper will allow any device connected to the bus, supporting sync transfers, to run sync. The 1542 will figure out which ones will run sync and which ones won't and handle them appropriately. There is no way to negotiate sync transfers via software. Roy Neese Adaptec Senior SCSI Applications Engineer UUCP @ neese@adaptex uunet!cs.utexas.edu!utacfd!merch!adaptex!neese
det@hawkmoon.MN.ORG (Derek E. Terveer) (05/28/91)
neese@adaptx1.UUCP writes: >>The AHA-1540A/1542A user's >>manual [(c) 1989] that i have for the 1542a states on page 3-2 that i >>must remove the terminators at locations RN3, RN4, and RN5. >The terminator resistors for the 1542A are located at RN3, RN4, and RN5. >The 1542A is a surface mount full length board. The only removeable parts >are the BIOS, firmware, and the resistor terminator packs. This is what i have. It is full length and is surface mounted. It has only a few chips that are removable and has a floppy connection. >>to the board and are labeled RN1, RN3, RN5, and RN6. They are scattered >>at various locations all over the board (RN1 by J1, RN3 by J4, RN5 and >>RN6 by the BIOS). Are the terminators for this board really the two >>removable resistor DIPS RN2 and RN4? If so, why did the board change >>the number of packs from 3 to 2 or from 2 to 3 (depending on which came >>first; my documentation or my board)? >Sounds like the 1540 adapter. This adapter is a TTL based adapters with only >one surface mount part (AIC-6250). The DIPS's are the terminator packs for >this adapter. Hmmm, but isn't the only (logical) difference between the 1540A and the 1542A the floppy support? I have floppy support on my board. derek -- Derek "Tigger" Terveer det@hawkmoon.MN.ORG -- U of MN Women's Lax I am the way and the truth and the light, I know all the answers; don't need your advice. -- "I am the way and the truth and the light" -- The Legendary Pink Dots
neese@adaptx1.UUCP (05/29/91)
>>>The AHA-1540A/1542A user's >>>manual [(c) 1989] that i have for the 1542a states on page 3-2 that i >>>must remove the terminators at locations RN3, RN4, and RN5. > >>The terminator resistors for the 1542A are located at RN3, RN4, and RN5. >>The 1542A is a surface mount full length board. The only removeable parts >>are the BIOS, firmware, and the resistor terminator packs. > >This is what i have. It is full length and is surface mounted. It has only >a few chips that are removable and has a floppy connection. > >>>to the board and are labeled RN1, RN3, RN5, and RN6. They are scattered >>>at various locations all over the board (RN1 by J1, RN3 by J4, RN5 and >>>RN6 by the BIOS). Are the terminators for this board really the two >>>removable resistor DIPS RN2 and RN4? If so, why did the board change >>>the number of packs from 3 to 2 or from 2 to 3 (depending on which came >>>first; my documentation or my board)? > >>Sounds like the 1540 adapter. This adapter is a TTL based adapters with only >>one surface mount part (AIC-6250). The DIPS's are the terminator packs for >>this adapter. > >Hmmm, but isn't the only (logical) difference between the 1540A and the 1542A >the floppy support? I have floppy support on my board. No, the AHA-1540 was the original adapter we did. It did not have room for the floppy controller as it was mostly TTL based with one surface mount chip (AIC-6250). This board was very crowded. Roy Neese Adaptec Senior SCSI Applications Engineer UUCP @ neese@adaptex uunet!cs.utexas.edu!utacfd!merch!adaptex!neese