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diff --git a/Documentation/m68k/README.buddha b/Documentation/m68k/README.buddha deleted file mode 100644 index 3ea9827ba3c7..000000000000 --- a/Documentation/m68k/README.buddha +++ /dev/null @@ -1,210 +0,0 @@ - -The Amiga Buddha and Catweasel IDE Driver (part of ide.c) was written by -Geert Uytterhoeven based on the following specifications: - ------------------------------------------------------------------------- - -Register map of the Buddha IDE controller and the -Buddha-part of the Catweasel Zorro-II version - -The Autoconfiguration has been implemented just as Commodore -described in their manuals, no tricks have been used (for -example leaving some address lines out of the equations...). -If you want to configure the board yourself (for example let -a Linux kernel configure the card), look at the Commodore -Docs. Reading the nibbles should give this information: - -Vendor number: 4626 ($1212) -product number: 0 (42 for Catweasel Z-II) -Serial number: 0 -Rom-vector: $1000 - -The card should be a Z-II board, size 64K, not for freemem -list, Rom-Vektor is valid, no second Autoconfig-board on the -same card, no space preference, supports "Shutup_forever". - -Setting the base address should be done in two steps, just -as the Amiga Kickstart does: The lower nibble of the 8-Bit -address is written to $4a, then the whole Byte is written to -$48, while it doesn't matter how often you're writing to $4a -as long as $48 is not touched. After $48 has been written, -the whole card disappears from $e8 and is mapped to the new -address just written. Make sure $4a is written before $48, -otherwise your chance is only 1:16 to find the board :-). - -The local memory-map is even active when mapped to $e8: - -$0-$7e Autokonfig-space, see Z-II docs. - -$80-$7fd reserved - -$7fe Speed-select Register: Read & Write - (description see further down) - -$800-$8ff IDE-Select 0 (Port 0, Register set 0) - -$900-$9ff IDE-Select 1 (Port 0, Register set 1) - -$a00-$aff IDE-Select 2 (Port 1, Register set 0) - -$b00-$bff IDE-Select 3 (Port 1, Register set 1) - -$c00-$cff IDE-Select 4 (Port 2, Register set 0, - Catweasel only!) - -$d00-$dff IDE-Select 5 (Port 3, Register set 1, - Catweasel only!) - -$e00-$eff local expansion port, on Catweasel Z-II the - Catweasel registers are also mapped here. - Never touch, use multidisk.device! - -$f00 read only, Byte-access: Bit 7 shows the - level of the IRQ-line of IDE port 0. - -$f01-$f3f mirror of $f00 - -$f40 read only, Byte-access: Bit 7 shows the - level of the IRQ-line of IDE port 1. - -$f41-$f7f mirror of $f40 - -$f80 read only, Byte-access: Bit 7 shows the - level of the IRQ-line of IDE port 2. - (Catweasel only!) - -$f81-$fbf mirror of $f80 - -$fc0 write-only: Writing any value to this - register enables IRQs to be passed from the - IDE ports to the Zorro bus. This mechanism - has been implemented to be compatible with - harddisks that are either defective or have - a buggy firmware and pull the IRQ line up - while starting up. If interrupts would - always be passed to the bus, the computer - might not start up. Once enabled, this flag - can not be disabled again. The level of the - flag can not be determined by software - (what for? Write to me if it's necessary!). - -$fc1-$fff mirror of $fc0 - -$1000-$ffff Buddha-Rom with offset $1000 in the rom - chip. The addresses $0 to $fff of the rom - chip cannot be read. Rom is Byte-wide and - mapped to even addresses. - -The IDE ports issue an INT2. You can read the level of the -IRQ-lines of the IDE-ports by reading from the three (two -for Buddha-only) registers $f00, $f40 and $f80. This way -more than one I/O request can be handled and you can easily -determine what driver has to serve the INT2. Buddha and -Catweasel expansion boards can issue an INT6. A separate -memory map is available for the I/O module and the sysop's -I/O module. - -The IDE ports are fed by the address lines A2 to A4, just as -the Amiga 1200 and Amiga 4000 IDE ports are. This way -existing drivers can be easily ported to Buddha. A move.l -polls two words out of the same address of IDE port since -every word is mirrored once. movem is not possible, but -it's not necessary either, because you can only speedup -68000 systems with this technique. A 68020 system with -fastmem is faster with move.l. - -If you're using the mirrored registers of the IDE-ports with -A6=1, the Buddha doesn't care about the speed that you have -selected in the speed register (see further down). With -A6=1 (for example $840 for port 0, register set 0), a 780ns -access is being made. These registers should be used for a -command access to the harddisk/CD-Rom, since command -accesses are Byte-wide and have to be made slower according -to the ATA-X3T9 manual. - -Now for the speed-register: The register is byte-wide, and -only the upper three bits are used (Bits 7 to 5). Bit 4 -must always be set to 1 to be compatible with later Buddha -versions (if I'll ever update this one). I presume that -I'll never use the lower four bits, but they have to be set -to 1 by definition. - The values in this table have to be shifted 5 bits to the -left and or'd with $1f (this sets the lower 5 bits). - -All the timings have in common: Select and IOR/IOW rise at -the same time. IOR and IOW have a propagation delay of -about 30ns to the clocks on the Zorro bus, that's why the -values are no multiple of 71. One clock-cycle is 71ns long -(exactly 70,5 at 14,18 Mhz on PAL systems). - -value 0 (Default after reset) - -497ns Select (7 clock cycles) , IOR/IOW after 172ns (2 clock cycles) -(same timing as the Amiga 1200 does on it's IDE port without -accelerator card) - -value 1 - -639ns Select (9 clock cycles), IOR/IOW after 243ns (3 clock cycles) - -value 2 - -781ns Select (11 clock cycles), IOR/IOW after 314ns (4 clock cycles) - -value 3 - -355ns Select (5 clock cycles), IOR/IOW after 101ns (1 clock cycle) - -value 4 - -355ns Select (5 clock cycles), IOR/IOW after 172ns (2 clock cycles) - -value 5 - -355ns Select (5 clock cycles), IOR/IOW after 243ns (3 clock cycles) - -value 6 - -1065ns Select (15 clock cycles), IOR/IOW after 314ns (4 clock cycles) - -value 7 - -355ns Select, (5 clock cycles), IOR/IOW after 101ns (1 clock cycle) - -When accessing IDE registers with A6=1 (for example $84x), -the timing will always be mode 0 8-bit compatible, no matter -what you have selected in the speed register: - -781ns select, IOR/IOW after 4 clock cycles (=314ns) aktive. - -All the timings with a very short select-signal (the 355ns -fast accesses) depend on the accelerator card used in the -system: Sometimes two more clock cycles are inserted by the -bus interface, making the whole access 497ns long. This -doesn't affect the reliability of the controller nor the -performance of the card, since this doesn't happen very -often. - -All the timings are calculated and only confirmed by -measurements that allowed me to count the clock cycles. If -the system is clocked by an oscillator other than 28,37516 -Mhz (for example the NTSC-frequency 28,63636 Mhz), each -clock cycle is shortened to a bit less than 70ns (not worth -mentioning). You could think of a small performance boost -by overclocking the system, but you would either need a -multisync monitor, or a graphics card, and your internal -diskdrive would go crazy, that's why you shouldn't tune your -Amiga this way. - -Giving you the possibility to write software that is -compatible with both the Buddha and the Catweasel Z-II, The -Buddha acts just like a Catweasel Z-II with no device -connected to the third IDE-port. The IRQ-register $f80 -always shows a "no IRQ here" on the Buddha, and accesses to -the third IDE port are going into data's Nirwana on the -Buddha. - - Jens Schönfeld february 19th, 1997 - updated may 27th, 1997 - eMail: sysop@nostlgic.tng.oche.de - |