Manual for 8 Meg Amiga Memory Board ----------------------------------- Phoenix MicroTechnologies, PTY. LTD. (08) 2938752 Australia Last Update 15/03/90 Version 1.08 ******************************************************************************* If you are having problems with expansion devices on an A1000 read the last section or contact us..If you are having problems with multiple devices on an A500-- CONGRATULATIONS you have the Worlds strongest 500 Power Supply. ******************************************************************************* Contents ~~~~~~~~ Expansion - Adding more memory Expansion over 2 Megabytes Memory Allocation Modifications and Bug Fixes Expansion Bus Problems on A1000s - C LTD etc. Expansion. Chips used are 256Kx4bit DRAMS, 20pin dual in line package. ~~~~~~~~~ Chip numbers are 414256 or 44C256 etc. -10 or -12 for speed. To open the Memory board case, first remove the six screws from the case (side farthest from A1000 or bottom on A500). Unscrew and disconnect the Autoconfig on/off switch.Remove the six 20mm spacers and separate the board from its casing. On the A500 the edge connector spacers have to be unscrewed from the case as well. Please refer to the two IFF pictures associated in this drawer when reading this section. If they are corrupt or missing please ring me to arrange replacement. Bare boards leave here tested to 512k so any calls staying that the board is nonfunctional will be viewed with skepticism (not impossible just unlikely). If you do not understand this section get someone who does. ALL MEMORY CHIPS are plugged in Notch or pin 1 UPPERMOST. View Copyright notice on component side of board (right hand edge) to determine up and dowm. ALL other chips are plugged in with pin 1 or notch to the RIGHT when viewed from component side. Chips are added in groups of 4 (512K) one to each data block as shown in the drawing RAM4 by the numbers and colored blocks. If you have the 7.5 Meg non-autoconfig board for use with the A1060 Sidecar then chips are installed starting from the number two positions not number one. Make sure all chips are correctly orientated and no pins are bent or misaligned. As more memory chips are added the autoconfig needs to tell the Amiga that more memory is present. The LINKBLOCK configuration needs to be changed to reflect this. There are four links on the block; the first is used to tell the Amiga whether to add the memory to the free memory list and is controlled by the toggle switch. The other three must be set in the following pattern to reflect the amount of memory on the board. Size Link2 Link3 Link4 512K in in in 1Meg in out in 2Meg in in out 4Meg in out out 8Meg out in in Refer to picture PCB4 which shows the solder side of the board under the chip labeled 573 on drawing RAM4. When expanding over 512K cut the two traces as shown by the green slash. When expanding over 1MEG cut the two traces as shown by the red slash. When expanding beyond 1MEGS both sets of traces should be cut. The two traces shown as shaded may also be cut as they are no longer needed so if you cut them by accident, no worries. Cut them very carefully with a Stanley knife, Xacto hobby knife or similar. Do not cut any other traces. On 8M1J boards the link block is replaced by a 4way DIP switch next to the 573 chip on RAM4 pic. All switches are on for 512K, only 1 & 3 are on for 1MEG and all are off for 2MEG. This does not apply to 7.5 Meg non-autoconfig boards. The above links and traces are not used with non-autoconfig boards. EXPANSION OVER 2 MEGABYTES. ~~~~~~~~~~~~~~~~~~~~~~~~~~~ Cut the two sets of traces mentioned in the previous paragraph and then proceed to the installation of a second PAL chip to allow for Amiga's positioning of the full 8Meg across an 8meg boundary. The chip to be replaced with the NUMBER2 PAL chip type 16L8A is located at the left centre of the board immediately above the centre of the edge connector. It's Location is shown as PAL#2 in the drawing RAM4. It is numbered xx74xxx688x or xx74xxx521x or both where the `x' equals manufacturers type codes which vary from time to time. Present chips are labeled MM74HCT688N and MC74HCT521N as an example. NUMBER2 PAL chips programmed by me are identified by a large `2' or `8M2' written in silver paint on the top of the chip. They are available from me for FREE or you may program your own. The specification is available from me and follows. This is a PALASM equation and should be run exactly as it appears as PALASM is very intolerant of errors. It appears elsewhere on this disk as AUTO8MPAL#2-3. Compare the two before using them. As this I.C. is not used, this is not necessary on nonautoconfig boards. ________________________________________________________________________________ PAL16L8 AUTO8MPAL2 AUTOCONFIG 8M PAL2 V1.03 ANDREW J WILSON 16 06 1988 COUT LD15 A23 LD13 A21 LD11L A19L 8M SP1 GND IP1 DA21 DA22 DA23 LD12L A20L LD14 A22 4502E VCC /4502E = /COUT*/LD15*/LD14*LD13*/A23*/A22*A21+8M*/COUT*/LD15*/LD14*LD13* /A23*A22+8M*/COUT*/LD15*/LD14*LD13*A23*/A22*/A21+/8M*/COUT*/LD15*/LD14*LD13 */A23*A22*/A21+8M*/LD12L /LD12L = /COUT*/LD15*LD14*/LD13*/A23*A22+8M*/COUT*/LD15*LD14*/LD13*A23*/A22*/A21+ $„ /COUT*/LD15*LD14*LD13*/A23*A22*A21+/COUT*/LD15*LD14*LD13*A23*/A22*/A21+/COUT* LD15*/LD14*/LD13*A23*/A22*/A21 /DA23 = /LD15*/LD14*LD13*/A23+/LD15*LD14*/LD13*/A22+/LD15*LD14*/LD13*/A23+ /LD15*LD14*LD13*/A22+/LD15*LD14*LD13*/A23+LD15*/LD14*/LD13*A23 /DA22 = /LD15*/LD14*LD13*/A22+/LD15*LD14*/LD13*A22*/A21+/LD15*LD14*LD13*A22+ LD15*/LD14*/LD13*/A22 /DA21 = /LD15*/LD14*LD13*/A21+/LD15*LD14*/LD13*A21+/LD15*LD14*LD13*/A21+LD15* /LD14*/LD13*A21 DESCRIPTION THIS IS 8MEG AUTOCONFIG PAL#2 FOR USE IN BOARDS OVER 2MEG _______________________________________________________________________________ MEMORY Allocation ~~~~~~~~~~~~~~~~~ This is automatic on Autoconfig Boards, usually from 200000H upward. In fact, the autoconfig board must be the first memory device on the bus in order to function correctly. If this is a problem then modifications can be made to your board but due to the limitations of current PAL chips it will mean more swapping of PALs as the board is expanded. On non-autoconfig boards memory is allocated from 200000H upward. If the board is 4 Meg or less then it occupies the 4 Meg space from 200000H to 5FFFFFH. MODIFICATIONS AND BUG FIXES ~~~~~~~~~~~~~~~~~~~~~~~~~~~ CASMOD ON 8M3B MEMORY BOARDS See CASMOD Picture in Docs Drawer for location of wires. This mod may be necessary for expansion over 2 Megabytes depending on the internal capacitance of the memory chips used. It has been done to all boards shipped after 1st July 1989 and to some before that. Any boards returned to me for upgrading will also have had it done. Boards returned to me will have this mod done without charge except for shipping. If you are doing this mod, use 28SWG Wire Wrap wire or similar and a suitable soldering iron (25Watt or similar). The mod is located on the solder side of the 8M3B board in the lower left area between the lower memory array and the support chips. Cut the two vertical tracks as shown in RED at the bottom of the drawing. Precut and tin suitable length wires for the connections shown in VIOLET, BLUE and GREEN. Solder wire ends to pads and holes as shown, where the wires are shown crossing other pads ignore this as the wires are attached only at their ends. Make sure that there are no shorts to adjacent pads particularly at the left hand end of the lower BLUE wire. When reassembling make sure that the wires pass between other pins and not over them as this could cause short circuits if the outer case puts any pressure on them. AUTOCONFIG PAL VERSION 1.3 AVAILABLE Version 1.3 of the Autoconfig PAL is necessary if you are using a CMI Accelerator Board or similar or if you wish to use a Sidecar with an Autoconfig 8 meg board. It corrects the omission of the /AS control signal from the equation for the data buffer chips. This is not normally a problem unless used with another device that has the same omission. EXPANSION PROBLEMS ON A1000s. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In spite of the problems detailed here the Amiga is still a great machine. If you had an Atari all this would pale into insignificance in the face of far greater problems and omissions. I know I've got one. SIDECAR AND EXPANSION PERIPHERALS The Sidecar (a German design like the A2000) was not designed to have any devices inserted between it and the Amiga. Due to a timing, capacitance, impedance matching, bus loading or whatever problem the Sidecar will not run reliably when separated from the Amiga by more than about 20mm. This is most noticeable when running a Hard Disk in the Sidecar with an Amiga partition. It does not matter whether the separation is caused by another board or a bus extention. Some A1000s will not run with a Sidecar at all, but this is caused by faulty PALs and 68000s as discussed in later paragraphs. If an A1000 is to run with a Sidecar and extra Memory etc. then PALs, Processer and distance between A1000 and Sidecar must all be A1. These problems also show up with internal memory boards as they also shift the processor away from the Sidecar. Expansion Boards that load the Expansion Bus unduly will also create problems. Expansion peripherals designed by me use CMOS buffers for lightest bus loads and maximum passthru expansion. Some products claiming to be CMOS actually only use CMOS memory chips and all other chips are TTL or Schottky As Commodore ignored all their own Bus specifications when designing the Sidecar and then failed to provide the internal memory expansion board for the Sidecar it is little wonder that it causes so many headaches. PAL PROBLEMS WITH EXPANSION DEVICES The following relates mainly to NTSC Amiga 1000's, if you are experiencing problems with an expansion device this is well worth reading. The PALS are available from me for $10.00 plus P&P $10.00 or less by snail mail. Other problems I have seen, usually with two or more expansion devices, are 68000s that are unable to stand the additional load. Commodore obviously does not test the machines with any load on the expansion bus before they ship them. Jerry Fox from Maroochydore in Qld has pointed out that Commodore have left out quite a few decoupling capacitors, which increases noise levels. If you are having problems or have Kickstart in ROM or other internal mods it would be a good idea to put these in. I will try to get a more complete description from him. *************************************************************************** IMPORTANT - READ THIS BEFORE READING THE C LTD DOCUMENT BELOW. NOVEMBER 1988. Most of the problems relating to the PALs on daughter-board A1000s using the Texas Instruments PALs are caused by a combination of poor earthing of some of the PALs on the daughter-board and the very high power consumption of the T.I. PALs compared to the MMI and National Semiconductor equivalents. Higher power consumption means increased noise problems particularly when power supply is marginal. A check of the operating temperatures of all of these devices shows that the T.I. devices are consuming a lot more power. Using faster devices helps mask this problem, but I have used slower (55nS) CMOS low power devices to achieve the same results. The standard PALs are 25ns devices. Some of the faster 15nS devices actually have lower power requirements. Improving the earthing of the PALs may solve your problems. Amazing Computing had a mod out for this but the first version's drawing was wrong, so make sure you get the right one. I will detail this mod on a later version of this manual. * * * * * * * CONFIRMED BUG FIX NOTIFICATION (CRITICAL) * * * * * * * This problem affects all Amiga owners using, or planning to use, expansion devices on the Amiga Expansion Bus. Definitions: Amiga Expansion Bus - the 86 pin edge card connector on the right side of your Amiga (See Amiga Owners Manual). Expansion Device - any device (such as an Expansion RAM, Hard Disk Drive Controller, 68020/68881 card, etc. ) that connects to the Amiga Expansion Bus. Amiga Daughter Board - the smaller of the two circuit boards inside the Amiga Computer, this board is mounted component side down, toward the front of the computer, is above the main board by about 1" and contains the WCS (KickStart) DRAMS and the AutoConfig PALs. Symptoms: The Amiga fails to recognize one or more Expansion Devices connected to the Amiga Expansion Bus, but the device(s) is/are known to be good and will work on other Amiga computers. An Amiga that crashes during the boot process at various stages, some times at a consistant place, other times not consistantly at any one point should be suspect. (NOTE: I saw a message recently about a guy having a problem with a Techni-Soft Board crashing during Start-up when he loaded his A-Time driver, some times it would work, some times it didn't. This is an example of a suspect Amiga. ) If the Amiga ever crashes all the way back to 'KickStart' this is a sure sign that that machine has a problem. The more Expansion Devices present on the Amiga Expansion Bus the more the problem exhibits itself. Also the farther the Amiga Expansion Bus is extended before termination, (ie. Techni-Soft RAM BOard and Pacific Cypress units especially the Pacific Cypress Bus Pass-Thru Board) the more problems will exist. Our experience in dealing with customers and dealers leads us to believe the following: 5 to 10 percent of ALL Amigas now in the field will not work consistantly with ONE Expansion Device. 25 to 35 percent of ALL Amigas now in the field will not work consistantly with TWO Expansion Devices. 75 to 85 percent of ALL Amigas now in the field will not work consistantly with THREE Expansion Devices. 99 percent of ALL Amigas now in the field will not work consistantly with FOUR Expansion Devices. (we know of 2) FIX: There is one solution available to fix the problem at this time and one additional solution that will be available in the near future. Fix #1 - AVAILABLE NOW - replace two PAL's (Part No. 16L8A) with their high speed versions (Part No. 16L8B). These PAL's are located on the Daughter Board in your Amiga, they are soldered directly into the board (NOT SOCKETED) and contain Commodore programming information. We (C Ltd. ) have (verbal) authority to reproduce this (non-copyrighted) code on the required high speed PALs. (Commodore does not have these parts available directly. ) We will sell a sell the required set of two PALs, programmed, with sockets and complete instructions for $20.00 plus $3.00 shipping expanse. You should be familiar with removing chips from multi-layer circuit boards to attempt to do this yourself, and be aware that this activity will void your Amiga's guarantee. Call our Customer Service Department or see your dealer to order these PAL kits. For those not wishing to attempt this themselves, or who are unable to locate a service center willing to do it, C Ltd. will replace the chips for a charge of $50.00, which includes chips, sockets and labor plus freight. C Ltd. then will guarantee the complete Daughter Board for 30 days and the C Ltd. supplied parts and labor for 90 days. C Ltd. will only work on complete systems, do not send the Daughter Board by itself, send the complete Amiga center section and all Expansion Devices (C Ltd. products need not be sent, we have plenty of them, also DO NOT send us a SideCar!) that you will be using in their original packages. Call our Customer Service Department for shipping information. This fix will allow a minimum of four devices to work on the Amiga Expansion Bus. -- BEWARE -- in most cases four Expansion Devices will pull more power from the Amiga Expansion Bus than is specified by Commodore-Amiga, be sure that you have sufficient power available by adding external power supplies with those devices that can use them. Fix #2 - Available in about 30 days - this will be another device that will plug into the Amiga Expansion Bus. C Ltd and MicroBotics are now involved in a joint venture to design and manufacture this device at the lowest possible cost so as to eliminate this problem once and for all. Only one such device is needed for up to five Expansion Devices, and probably, only one such device will be able to reside on the Amiga Expansion Bus at any given time, so the probability of building this device into our future products is not very high. We would like to thank Rick Sterling of Commodore- Amiga, Jerry Robbinson of MicroBotics and Kelley McArthur of CreativeMicroSystems for their assistance and hard work in locating and solving this problem. NOTES: This problem stems from the speed of the PAL chips used by Commodore in the manufacture of the Amiga. Early Amigas used PALs manufactured by MMI, and these chips seemed to work well in almost every case, but at some point Commodore started using PALs made by Texas Instruments. The TI PALs, though having the same rating as the MMI parts, simply do not perform as well causing the problems as stated above. Replacing the parts with the much faster 16L8B part (any manufacturer's "B" versions are fast enough) solves the problem. We have reserched this problem to 'death' and are confidant both from analysis of the system with the Texas Instrument PALs and from experimental analysis of the system with the faster 16L8B PALs that we know what the problem is and how to fix it. Some have suggested buffering the pass-through on each device. While this would solve the problem for up to two Expansion Devices, it would not permit going beyond that number. Because there is a delay of the signal each time it is buffered, more than two buffers in line would take the signal out of the allowed timing cycle allowed on the Amiga Expansion Bus. Others have suggested termination of the bus. While each Expansion Device could have its own termination resistance, the total resistance on the Amiga Expansion Bus would be exceed the allowed specifications when two or more devices were so terminated, causing probable failure of the 68000 microprocessor. A termination scheme could be devised that would terminate the bus properly if the exact combined total Resistance, Capacitance and Inductance of all devices on the bus were known. This would however prevent the user from adding additional devices or temporialy removing one. So in conclusion, the best solution to the problem is replace the PALs. By the way, if there is blame in this matter it is probably on the shoulders of Texas Instruments and their PAL chips. Please Post This Message To Other Boards Where Possible. E. J. Lippert II C Ltd. Wichita, KS (316) 267-6321 ________________________________________________________________________________ ________________________________________________________________________________