1 ===================================== 2 Amiga Buddha and Catweasel IDE Driver 3 ===================================== 4 5 The Amiga Buddha and Catweasel IDE Driver (part of ide.c) was written by 6 Geert Uytterhoeven based on the following specifications: 7 8 ------------------------------------------------------------------------ 9 10 Register map of the Buddha IDE controller and the 11 Buddha-part of the Catweasel Zorro-II version 12 13 The Autoconfiguration has been implemented just as Commodore 14 described in their manuals, no tricks have been used (for 15 example leaving some address lines out of the equations...). 16 If you want to configure the board yourself (for example let 17 a Linux kernel configure the card), look at the Commodore 18 Docs. Reading the nibbles should give this information:: 19 20 Vendor number: 4626 ($1212) 21 product number: 0 (42 for Catweasel Z-II) 22 Serial number: 0 23 Rom-vector: $1000 24 25 The card should be a Z-II board, size 64K, not for freemem 26 list, Rom-Vektor is valid, no second Autoconfig-board on the 27 same card, no space preference, supports "Shutup_forever". 28 29 Setting the base address should be done in two steps, just 30 as the Amiga Kickstart does: The lower nibble of the 8-Bit 31 address is written to $4a, then the whole Byte is written to 32 $48, while it doesn't matter how often you're writing to $4a 33 as long as $48 is not touched. After $48 has been written, 34 the whole card disappears from $e8 and is mapped to the new 35 address just written. Make sure $4a is written before $48, 36 otherwise your chance is only 1:16 to find the board :-). 37 38 The local memory-map is even active when mapped to $e8: 39 40 ============== =========================================== 41 $0-$7e Autokonfig-space, see Z-II docs. 42 43 $80-$7fd reserved 44 45 $7fe Speed-select Register: Read & Write 46 (description see further down) 47 48 $800-$8ff IDE-Select 0 (Port 0, Register set 0) 49 50 $900-$9ff IDE-Select 1 (Port 0, Register set 1) 51 52 $a00-$aff IDE-Select 2 (Port 1, Register set 0) 53 54 $b00-$bff IDE-Select 3 (Port 1, Register set 1) 55 56 $c00-$cff IDE-Select 4 (Port 2, Register set 0, 57 Catweasel only!) 58 59 $d00-$dff IDE-Select 5 (Port 3, Register set 1, 60 Catweasel only!) 61 62 $e00-$eff local expansion port, on Catweasel Z-II the 63 Catweasel registers are also mapped here. 64 Never touch, use multidisk.device! 65 66 $f00 read only, Byte-access: Bit 7 shows the 67 level of the IRQ-line of IDE port 0. 68 69 $f01-$f3f mirror of $f00 70 71 $f40 read only, Byte-access: Bit 7 shows the 72 level of the IRQ-line of IDE port 1. 73 74 $f41-$f7f mirror of $f40 75 76 $f80 read only, Byte-access: Bit 7 shows the 77 level of the IRQ-line of IDE port 2. 78 (Catweasel only!) 79 80 $f81-$fbf mirror of $f80 81 82 $fc0 write-only: Writing any value to this 83 register enables IRQs to be passed from the 84 IDE ports to the Zorro bus. This mechanism 85 has been implemented to be compatible with 86 harddisks that are either defective or have 87 a buggy firmware and pull the IRQ line up 88 while starting up. If interrupts would 89 always be passed to the bus, the computer 90 might not start up. Once enabled, this flag 91 can not be disabled again. The level of the 92 flag can not be determined by software 93 (what for? Write to me if it's necessary!). 94 95 $fc1-$fff mirror of $fc0 96 97 $1000-$ffff Buddha-Rom with offset $1000 in the rom 98 chip. The addresses $0 to $fff of the rom 99 chip cannot be read. Rom is Byte-wide and 100 mapped to even addresses. 101 ============== =========================================== 102 103 The IDE ports issue an INT2. You can read the level of the 104 IRQ-lines of the IDE-ports by reading from the three (two 105 for Buddha-only) registers $f00, $f40 and $f80. This way 106 more than one I/O request can be handled and you can easily 107 determine what driver has to serve the INT2. Buddha and 108 Catweasel expansion boards can issue an INT6. A separate 109 memory map is available for the I/O module and the sysop's 110 I/O module. 111 112 The IDE ports are fed by the address lines A2 to A4, just as 113 the Amiga 1200 and Amiga 4000 IDE ports are. This way 114 existing drivers can be easily ported to Buddha. A move.l 115 polls two words out of the same address of IDE port since 116 every word is mirrored once. movem is not possible, but 117 it's not necessary either, because you can only speedup 118 68000 systems with this technique. A 68020 system with 119 fastmem is faster with move.l. 120 121 If you're using the mirrored registers of the IDE-ports with 122 A6=1, the Buddha doesn't care about the speed that you have 123 selected in the speed register (see further down). With 124 A6=1 (for example $840 for port 0, register set 0), a 780ns 125 access is being made. These registers should be used for a 126 command access to the harddisk/CD-Rom, since command 127 accesses are Byte-wide and have to be made slower according 128 to the ATA-X3T9 manual. 129 130 Now for the speed-register: The register is byte-wide, and 131 only the upper three bits are used (Bits 7 to 5). Bit 4 132 must always be set to 1 to be compatible with later Buddha 133 versions (if I'll ever update this one). I presume that 134 I'll never use the lower four bits, but they have to be set 135 to 1 by definition. 136 137 The values in this table have to be shifted 5 bits to the 138 left and or'd with $1f (this sets the lower 5 bits). 139 140 All the timings have in common: Select and IOR/IOW rise at 141 the same time. IOR and IOW have a propagation delay of 142 about 30ns to the clocks on the Zorro bus, that's why the 143 values are no multiple of 71. One clock-cycle is 71ns long 144 (exactly 70,5 at 14,18 Mhz on PAL systems). 145 146 value 0 (Default after reset) 147 497ns Select (7 clock cycles) , IOR/IOW after 172ns (2 clock cycles) 148 (same timing as the Amiga 1200 does on it's IDE port without 149 accelerator card) 150 151 value 1 152 639ns Select (9 clock cycles), IOR/IOW after 243ns (3 clock cycles) 153 154 value 2 155 781ns Select (11 clock cycles), IOR/IOW after 314ns (4 clock cycles) 156 157 value 3 158 355ns Select (5 clock cycles), IOR/IOW after 101ns (1 clock cycle) 159 160 value 4 161 355ns Select (5 clock cycles), IOR/IOW after 172ns (2 clock cycles) 162 163 value 5 164 355ns Select (5 clock cycles), IOR/IOW after 243ns (3 clock cycles) 165 166 value 6 167 1065ns Select (15 clock cycles), IOR/IOW after 314ns (4 clock cycles) 168 169 value 7 170 355ns Select, (5 clock cycles), IOR/IOW after 101ns (1 clock cycle) 171 172 When accessing IDE registers with A6=1 (for example $84x), 173 the timing will always be mode 0 8-bit compatible, no matter 174 what you have selected in the speed register: 175 176 781ns select, IOR/IOW after 4 clock cycles (=314ns) active. 177 178 All the timings with a very short select-signal (the 355ns 179 fast accesses) depend on the accelerator card used in the 180 system: Sometimes two more clock cycles are inserted by the 181 bus interface, making the whole access 497ns long. This 182 doesn't affect the reliability of the controller nor the 183 performance of the card, since this doesn't happen very 184 often. 185 186 All the timings are calculated and only confirmed by 187 measurements that allowed me to count the clock cycles. If 188 the system is clocked by an oscillator other than 28,37516 189 Mhz (for example the NTSC-frequency 28,63636 Mhz), each 190 clock cycle is shortened to a bit less than 70ns (not worth 191 mentioning). You could think of a small performance boost 192 by overclocking the system, but you would either need a 193 multisync monitor, or a graphics card, and your internal 194 diskdrive would go crazy, that's why you shouldn't tune your 195 Amiga this way. 196 197 Giving you the possibility to write software that is 198 compatible with both the Buddha and the Catweasel Z-II, The 199 Buddha acts just like a Catweasel Z-II with no device 200 connected to the third IDE-port. The IRQ-register $f80 201 always shows a "no IRQ here" on the Buddha, and accesses to 202 the third IDE port are going into data's Nirwana on the 203 Buddha. 204 205 Jens Schönfeld february 19th, 1997 206 207 updated may 27th, 1997 208 209 eMail: sysop@nostlgic.tng.oche.de
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