1 2The Amiga Buddha and Catweasel IDE Driver (part of ide.c) was written by 3Geert Uytterhoeven based on the following specifications: 4 5------------------------------------------------------------------------ 6 7Register map of the Buddha IDE controller and the 8Buddha-part of the Catweasel Zorro-II version 9 10The Autoconfiguration has been implemented just as Commodore 11described in their manuals, no tricks have been used (for 12example leaving some address lines out of the equations...). 13If you want to configure the board yourself (for example let 14a Linux kernel configure the card), look at the Commodore 15Docs. Reading the nibbles should give this information: 16 17Vendor number: 4626 ($1212) 18product number: 0 (42 for Catweasel Z-II) 19Serial number: 0 20Rom-vector: $1000 21 22The card should be a Z-II board, size 64K, not for freemem 23list, Rom-Vektor is valid, no second Autoconfig-board on the 24same card, no space preference, supports "Shutup_forever". 25 26Setting the base address should be done in two steps, just 27as the Amiga Kickstart does: The lower nibble of the 8-Bit 28address is written to $4a, then the whole Byte is written to 29$48, while it doesn't matter how often you're writing to $4a 30as long as $48 is not touched. After $48 has been written, 31the whole card disappears from $e8 and is mapped to the new 32address just written. Make sure $4a is written before $48, 33otherwise your chance is only 1:16 to find the board :-). 34 35The local memory-map is even active when mapped to $e8: 36 37$0-$7e Autokonfig-space, see Z-II docs. 38 39$80-$7fd reserved 40 41$7fe Speed-select Register: Read & Write 42 (description see further down) 43 44$800-$8ff IDE-Select 0 (Port 0, Register set 0) 45 46$900-$9ff IDE-Select 1 (Port 0, Register set 1) 47 48$a00-$aff IDE-Select 2 (Port 1, Register set 0) 49 50$b00-$bff IDE-Select 3 (Port 1, Register set 1) 51 52$c00-$cff IDE-Select 4 (Port 2, Register set 0, 53 Catweasel only!) 54 55$d00-$dff IDE-Select 5 (Port 3, Register set 1, 56 Catweasel only!) 57 58$e00-$eff local expansion port, on Catweasel Z-II the 59 Catweasel registers are also mapped here. 60 Never touch, use multidisk.device! 61 62$f00 read only, Byte-access: Bit 7 shows the 63 level of the IRQ-line of IDE port 0. 64 65$f01-$f3f mirror of $f00 66 67$f40 read only, Byte-access: Bit 7 shows the 68 level of the IRQ-line of IDE port 1. 69 70$f41-$f7f mirror of $f40 71 72$f80 read only, Byte-access: Bit 7 shows the 73 level of the IRQ-line of IDE port 2. 74 (Catweasel only!) 75 76$f81-$fbf mirror of $f80 77 78$fc0 write-only: Writing any value to this 79 register enables IRQs to be passed from the 80 IDE ports to the Zorro bus. This mechanism 81 has been implemented to be compatible with 82 harddisks that are either defective or have 83 a buggy firmware and pull the IRQ line up 84 while starting up. If interrupts would 85 always be passed to the bus, the computer 86 might not start up. Once enabled, this flag 87 can not be disabled again. The level of the 88 flag can not be determined by software 89 (what for? Write to me if it's necessary!). 90 91$fc1-$fff mirror of $fc0 92 93$1000-$ffff Buddha-Rom with offset $1000 in the rom 94 chip. The addresses $0 to $fff of the rom 95 chip cannot be read. Rom is Byte-wide and 96 mapped to even addresses. 97 98The IDE ports issue an INT2. You can read the level of the 99IRQ-lines of the IDE-ports by reading from the three (two 100for Buddha-only) registers $f00, $f40 and $f80. This way 101more than one I/O request can be handled and you can easily 102determine what driver has to serve the INT2. Buddha and 103Catweasel expansion boards can issue an INT6. A separate 104memory map is available for the I/O module and the sysop's 105I/O module. 106 107The IDE ports are fed by the address lines A2 to A4, just as 108the Amiga 1200 and Amiga 4000 IDE ports are. This way 109existing drivers can be easily ported to Buddha. A move.l 110polls two words out of the same address of IDE port since 111every word is mirrored once. movem is not possible, but 112it's not necessary either, because you can only speedup 11368000 systems with this technique. A 68020 system with 114fastmem is faster with move.l. 115 116If you're using the mirrored registers of the IDE-ports with 117A6=1, the Buddha doesn't care about the speed that you have 118selected in the speed register (see further down). With 119A6=1 (for example $840 for port 0, register set 0), a 780ns 120access is being made. These registers should be used for a 121command access to the harddisk/CD-Rom, since command 122accesses are Byte-wide and have to be made slower according 123to the ATA-X3T9 manual. 124 125Now for the speed-register: The register is byte-wide, and 126only the upper three bits are used (Bits 7 to 5). Bit 4 127must always be set to 1 to be compatible with later Buddha 128versions (if I'll ever update this one). I presume that 129I'll never use the lower four bits, but they have to be set 130to 1 by definition. 131 The values in this table have to be shifted 5 bits to the 132left and or'd with $1f (this sets the lower 5 bits). 133 134All the timings have in common: Select and IOR/IOW rise at 135the same time. IOR and IOW have a propagation delay of 136about 30ns to the clocks on the Zorro bus, that's why the 137values are no multiple of 71. One clock-cycle is 71ns long 138(exactly 70,5 at 14,18 Mhz on PAL systems). 139 140value 0 (Default after reset) 141 142497ns Select (7 clock cycles) , IOR/IOW after 172ns (2 clock cycles) 143(same timing as the Amiga 1200 does on it's IDE port without 144accelerator card) 145 146value 1 147 148639ns Select (9 clock cycles), IOR/IOW after 243ns (3 clock cycles) 149 150value 2 151 152781ns Select (11 clock cycles), IOR/IOW after 314ns (4 clock cycles) 153 154value 3 155 156355ns Select (5 clock cycles), IOR/IOW after 101ns (1 clock cycle) 157 158value 4 159 160355ns Select (5 clock cycles), IOR/IOW after 172ns (2 clock cycles) 161 162value 5 163 164355ns Select (5 clock cycles), IOR/IOW after 243ns (3 clock cycles) 165 166value 6 167 1681065ns Select (15 clock cycles), IOR/IOW after 314ns (4 clock cycles) 169 170value 7 171 172355ns Select, (5 clock cycles), IOR/IOW after 101ns (1 clock cycle) 173 174When accessing IDE registers with A6=1 (for example $84x), 175the timing will always be mode 0 8-bit compatible, no matter 176what you have selected in the speed register: 177 178781ns select, IOR/IOW after 4 clock cycles (=314ns) aktive. 179 180All the timings with a very short select-signal (the 355ns 181fast accesses) depend on the accelerator card used in the 182system: Sometimes two more clock cycles are inserted by the 183bus interface, making the whole access 497ns long. This 184doesn't affect the reliability of the controller nor the 185performance of the card, since this doesn't happen very 186often. 187 188All the timings are calculated and only confirmed by 189measurements that allowed me to count the clock cycles. If 190the system is clocked by an oscillator other than 28,37516 191Mhz (for example the NTSC-frequency 28,63636 Mhz), each 192clock cycle is shortened to a bit less than 70ns (not worth 193mentioning). You could think of a small performance boost 194by overclocking the system, but you would either need a 195multisync monitor, or a graphics card, and your internal 196diskdrive would go crazy, that's why you shouldn't tune your 197Amiga this way. 198 199Giving you the possibility to write software that is 200compatible with both the Buddha and the Catweasel Z-II, The 201Buddha acts just like a Catweasel Z-II with no device 202connected to the third IDE-port. The IRQ-register $f80 203always shows a "no IRQ here" on the Buddha, and accesses to 204the third IDE port are going into data's Nirwana on the 205Buddha. 206 207 Jens Schönfeld february 19th, 1997 208 updated may 27th, 1997 209 eMail: sysop@nostlgic.tng.oche.de 210 211
