Based on kernel version 4.16.1. Page generated on 2018-04-09 11:53 EST.
1 2 The Amiga Buddha and Catweasel IDE Driver (part of ide.c) was written by 3 Geert Uytterhoeven based on the following specifications: 4 5 ------------------------------------------------------------------------ 6 7 Register map of the Buddha IDE controller and the 8 Buddha-part of the Catweasel Zorro-II version 9 10 The Autoconfiguration has been implemented just as Commodore 11 described in their manuals, no tricks have been used (for 12 example leaving some address lines out of the equations...). 13 If you want to configure the board yourself (for example let 14 a Linux kernel configure the card), look at the Commodore 15 Docs. Reading the nibbles should give this information: 16 17 Vendor number: 4626 ($1212) 18 product number: 0 (42 for Catweasel Z-II) 19 Serial number: 0 20 Rom-vector: $1000 21 22 The card should be a Z-II board, size 64K, not for freemem 23 list, Rom-Vektor is valid, no second Autoconfig-board on the 24 same card, no space preference, supports "Shutup_forever". 25 26 Setting the base address should be done in two steps, just 27 as the Amiga Kickstart does: The lower nibble of the 8-Bit 28 address 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 30 as long as $48 is not touched. After $48 has been written, 31 the whole card disappears from $e8 and is mapped to the new 32 address just written. Make sure $4a is written before $48, 33 otherwise your chance is only 1:16 to find the board :-). 34 35 The 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 98 The IDE ports issue an INT2. You can read the level of the 99 IRQ-lines of the IDE-ports by reading from the three (two 100 for Buddha-only) registers $f00, $f40 and $f80. This way 101 more than one I/O request can be handled and you can easily 102 determine what driver has to serve the INT2. Buddha and 103 Catweasel expansion boards can issue an INT6. A separate 104 memory map is available for the I/O module and the sysop's 105 I/O module. 106 107 The IDE ports are fed by the address lines A2 to A4, just as 108 the Amiga 1200 and Amiga 4000 IDE ports are. This way 109 existing drivers can be easily ported to Buddha. A move.l 110 polls two words out of the same address of IDE port since 111 every word is mirrored once. movem is not possible, but 112 it's not necessary either, because you can only speedup 113 68000 systems with this technique. A 68020 system with 114 fastmem is faster with move.l. 115 116 If you're using the mirrored registers of the IDE-ports with 117 A6=1, the Buddha doesn't care about the speed that you have 118 selected in the speed register (see further down). With 119 A6=1 (for example $840 for port 0, register set 0), a 780ns 120 access is being made. These registers should be used for a 121 command access to the harddisk/CD-Rom, since command 122 accesses are Byte-wide and have to be made slower according 123 to the ATA-X3T9 manual. 124 125 Now for the speed-register: The register is byte-wide, and 126 only the upper three bits are used (Bits 7 to 5). Bit 4 127 must always be set to 1 to be compatible with later Buddha 128 versions (if I'll ever update this one). I presume that 129 I'll never use the lower four bits, but they have to be set 130 to 1 by definition. 131 The values in this table have to be shifted 5 bits to the 132 left and or'd with $1f (this sets the lower 5 bits). 133 134 All the timings have in common: Select and IOR/IOW rise at 135 the same time. IOR and IOW have a propagation delay of 136 about 30ns to the clocks on the Zorro bus, that's why the 137 values are no multiple of 71. One clock-cycle is 71ns long 138 (exactly 70,5 at 14,18 Mhz on PAL systems). 139 140 value 0 (Default after reset) 141 142 497ns 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 144 accelerator card) 145 146 value 1 147 148 639ns Select (9 clock cycles), IOR/IOW after 243ns (3 clock cycles) 149 150 value 2 151 152 781ns Select (11 clock cycles), IOR/IOW after 314ns (4 clock cycles) 153 154 value 3 155 156 355ns Select (5 clock cycles), IOR/IOW after 101ns (1 clock cycle) 157 158 value 4 159 160 355ns Select (5 clock cycles), IOR/IOW after 172ns (2 clock cycles) 161 162 value 5 163 164 355ns Select (5 clock cycles), IOR/IOW after 243ns (3 clock cycles) 165 166 value 6 167 168 1065ns Select (15 clock cycles), IOR/IOW after 314ns (4 clock cycles) 169 170 value 7 171 172 355ns Select, (5 clock cycles), IOR/IOW after 101ns (1 clock cycle) 173 174 When accessing IDE registers with A6=1 (for example $84x), 175 the timing will always be mode 0 8-bit compatible, no matter 176 what you have selected in the speed register: 177 178 781ns select, IOR/IOW after 4 clock cycles (=314ns) aktive. 179 180 All the timings with a very short select-signal (the 355ns 181 fast accesses) depend on the accelerator card used in the 182 system: Sometimes two more clock cycles are inserted by the 183 bus interface, making the whole access 497ns long. This 184 doesn't affect the reliability of the controller nor the 185 performance of the card, since this doesn't happen very 186 often. 187 188 All the timings are calculated and only confirmed by 189 measurements that allowed me to count the clock cycles. If 190 the system is clocked by an oscillator other than 28,37516 191 Mhz (for example the NTSC-frequency 28,63636 Mhz), each 192 clock cycle is shortened to a bit less than 70ns (not worth 193 mentioning). You could think of a small performance boost 194 by overclocking the system, but you would either need a 195 multisync monitor, or a graphics card, and your internal 196 diskdrive would go crazy, that's why you shouldn't tune your 197 Amiga this way. 198 199 Giving you the possibility to write software that is 200 compatible with both the Buddha and the Catweasel Z-II, The 201 Buddha acts just like a Catweasel Z-II with no device 202 connected to the third IDE-port. The IRQ-register $f80 203 always shows a "no IRQ here" on the Buddha, and accesses to 204 the third IDE port are going into data's Nirwana on the 205 Buddha. 206 207 Jens Schönfeld february 19th, 1997 208 updated may 27th, 1997 209 eMail: sysop@nostlgic.tng.oche.de