| /* i8255.c: Intel i8255 PIO adapter | |
| Copyright (c) 2010, William A. Beech | |
| Permission is hereby granted, free of charge, to any person obtaining a | |
| copy of this software and associated documentation files (the "Software"), | |
| to deal in the Software without restriction, including without limitation | |
| the rights to use, copy, modify, merge, publish, distribute, sublicense, | |
| and/or sell copies of the Software, and to permit persons to whom the | |
| Software is furnished to do so, subject to the following conditions: | |
| The above copyright notice and this permission notice shall be included in | |
| all copies or substantial portions of the Software. | |
| THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
| IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
| FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL | |
| WILLIAM A. BEECH BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER | |
| IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN | |
| CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. | |
| Except as contained in this notice, the name of William A. Beech shall not be | |
| used in advertising or otherwise to promote the sale, use or other dealings | |
| in this Software without prior written authorization from William A. Beech. | |
| MODIFICATIONS: | |
| ?? ??? 10 - Original file. | |
| 16 Dec 12 - Modified to use isbc_80_10.cfg file to set baseport and size. | |
| 24 Apr 15 -- Modified to use simh_debug | |
| NOTES: | |
| These functions support a simulated i8255 interface device on an iSBC. | |
| The device has threee physical 8-bit I/O ports which could be connected | |
| to any parallel I/O device. | |
| All I/O is via programmed I/O. The i8255 has a control port (i8255s) | |
| and three data ports (i8255a, i8255b, and i8255c). | |
| The simulated device supports a select from I/O space and two address lines. | |
| The data ports are at the lower addresses and the control port is at | |
| the highest. | |
| A write to the control port can configure the device: | |
| Control Word | |
| +---+---+---+---+---+---+---+---+ | |
| | D7 D6 D5 D4 D3 D2 D1 D0| | |
| +---+---+---+---+---+---+---+---+ | |
| Group B | |
| D0 Port C (lower) 1-Input, 0-Output | |
| D1 Port B 1-Input, 0-Output | |
| D2 Mode Selection 0-Mode 0, 1-Mode 1 | |
| Group A | |
| D3 Port C (upper) 1-Input, 0-Output | |
| D4 Port A 1-Input, 0-Output | |
| D5-6 Mode Selection 00-Mode 0, 01-Mode 1, 1X-Mode 2 | |
| D7 Mode Set Flag 1=Active, 0=Bit Set | |
| Mode 0 - Basic Input/Output | |
| Mode 1 - Strobed Input/Output | |
| Mode 2 - Bidirectional Bus | |
| Bit Set - D7=0, D3:1 select port C bit, D0 1=set, 0=reset | |
| A read to the data ports gets the current port value, a write | |
| to the data ports writes the character to the device. | |
| This program simulates up to 4 i8255 devices. It handles 2 i8255 | |
| devices on the iSBC 80/10 SBC. Other devices could be on other | |
| multibus boards in the simulated system. | |
| */ | |
| #include "system_defs.h" /* system header in system dir */ | |
| #define DEBUG 0 | |
| /* external globals */ | |
| extern uint16 port; //port called in dev_table[port] | |
| /* function prototypes */ | |
| t_stat i8255_reset (DEVICE *dptr, uint16 baseport); | |
| uint8 i8255_get_dn(void); | |
| uint8 i8255a(t_bool io, uint8 data); | |
| uint8 i8255b(t_bool io, uint8 data); | |
| uint8 i8255c(t_bool io, uint8 data); | |
| uint8 i8255s(t_bool io, uint8 data); | |
| /* external function prototypes */ | |
| extern uint16 reg_dev(uint8 (*routine)(t_bool, uint8), uint16, uint8); | |
| /* globals */ | |
| int32 i8255_devnum = 0; //actual number of 8255 instances + 1 | |
| uint16 i8255_port[4]; //baseport port registered to each instance | |
| /* these bytes represent the input and output to/from a port instance */ | |
| uint8 i8255_A[4]; //port A byte I/O | |
| uint8 i8255_B[4]; //port B byte I/O | |
| uint8 i8255_C[4]; //port C byte I/O | |
| /* i8255 Standard I/O Data Structures */ | |
| /* up to 4 i8255 devices */ | |
| UNIT i8255_unit[] = { | |
| { UDATA (0, 0, 0) }, /* i8255 0 */ | |
| { UDATA (0, 0, 0) }, /* i8255 1 */ | |
| { UDATA (0, 0, 0) }, /* i8255 2 */ | |
| { UDATA (0, 0, 0) } /* i8255 3 */ | |
| }; | |
| REG i8255_reg[] = { | |
| { HRDATA (CS0, i8255_unit[0].u3, 8) }, /* i8255 0 */ | |
| { HRDATA (A0, i8255_A[0], 8) }, | |
| { HRDATA (B0, i8255_B[0], 8) }, | |
| { HRDATA (C0, i8255_C[0], 8) }, | |
| { HRDATA (CS1, i8255_unit[1].u3, 8) }, /* i8255 1 */ | |
| { HRDATA (A1, i8255_A[1], 8) }, | |
| { HRDATA (B1, i8255_B[1], 8) }, | |
| { HRDATA (C1, i8255_C[1], 8) }, | |
| { HRDATA (CS2, i8255_unit[2].u3, 8) }, /* i8255 2 */ | |
| { HRDATA (A2, i8255_A[2], 8) }, | |
| { HRDATA (B2, i8255_B[2], 8) }, | |
| { HRDATA (C2, i8255_C[2], 8) }, | |
| { HRDATA (CS3, i8255_unit[3].u3, 8) }, /* i8255 3 */ | |
| { HRDATA (A3, i8255_A[3], 8) }, | |
| { HRDATA (B3, i8255_B[3], 8) }, | |
| { HRDATA (C3, i8255_C[3], 8) }, | |
| { NULL } | |
| }; | |
| DEBTAB i8255_debug[] = { | |
| { "ALL", DEBUG_all }, | |
| { "FLOW", DEBUG_flow }, | |
| { "READ", DEBUG_read }, | |
| { "WRITE", DEBUG_write }, | |
| { "LEV1", DEBUG_level1 }, | |
| { "LEV2", DEBUG_level2 }, | |
| { NULL } | |
| }; | |
| /* address width is set to 16 bits to use devices in 8086/8088 implementations */ | |
| DEVICE i8255_dev = { | |
| "I8255", //name | |
| i8255_unit, //units | |
| i8255_reg, //registers | |
| NULL, //modifiers | |
| 1, //numunits | |
| 16, //aradix | |
| 16, //awidth | |
| 1, //aincr | |
| 16, //dradix | |
| 8, //dwidth | |
| NULL, //examine | |
| NULL, //deposit | |
| // i8255_reset2(), //reset | |
| NULL, //reset | |
| NULL, //boot | |
| NULL, //attach | |
| NULL, //detach | |
| NULL, //ctxt | |
| 0, //flags | |
| 0, //dctrl | |
| i8255_debug, //debflags | |
| NULL, //msize | |
| NULL //lname | |
| }; | |
| /* Reset routine */ | |
| t_stat i8255_reset (DEVICE *dptr, uint16 baseport) | |
| { | |
| if (i8255_devnum > I8255_NUM) { | |
| sim_printf("i8255_reset: too many devices!\n"); | |
| return SCPE_MEM; | |
| } | |
| sim_printf(" 8255-%d: Reset\n", i8255_devnum); | |
| sim_printf(" 8255-%d: Registered at %04X\n", i8255_devnum, baseport); | |
| i8255_port[i8255_devnum] = baseport; | |
| reg_dev(i8255a, baseport, i8255_devnum); | |
| reg_dev(i8255b, baseport + 1, i8255_devnum); | |
| reg_dev(i8255c, baseport + 2, i8255_devnum); | |
| reg_dev(i8255s, baseport + 3, i8255_devnum); | |
| i8255_unit[i8255_devnum].u3 = 0x9B; /* control */ | |
| i8255_A[i8255_devnum] = 0xFF; /* Port A */ | |
| i8255_B[i8255_devnum] = 0xFF; /* Port B */ | |
| i8255_C[i8255_devnum] = 0xFF; /* Port C */ | |
| i8255_devnum++; | |
| return SCPE_OK; | |
| } | |
| uint8 i8255_get_dn(void) | |
| { | |
| int i; | |
| for (i=0; i<I8255_NUM; i++) | |
| if (port >=i8255_port[i] && port <= i8255_port[i] + 3) | |
| return i; | |
| sim_printf("i8255_get_dn: port %04X not in 8255 device table\n", port); | |
| return 0xFF; | |
| } | |
| /* I/O instruction handlers, called from the CPU module when an | |
| IN or OUT instruction is issued. | |
| */ | |
| /* i8255 functions */ | |
| uint8 i8255s(t_bool io, uint8 data) | |
| { | |
| uint8 bit; | |
| uint8 devnum; | |
| if ((devnum = i8255_get_dn()) != 0xFF) { | |
| if (io == 0) { /* read status port */ | |
| return 0xFF; //undefined | |
| } else { /* write status port */ | |
| if (data & 0x80) { /* mode instruction */ | |
| i8255_unit[devnum].u3 = data; | |
| if (DEBUG) | |
| sim_printf(" 8255-%d: Mode Instruction=%02X\n", devnum, data); | |
| if (data & 0x64) | |
| sim_printf(" Mode 1 and 2 not yet implemented\n"); | |
| } else { /* bit set */ | |
| bit = (data & 0x0E) >> 1; /* get bit number */ | |
| if (data & 0x01) { /* set bit */ | |
| i8255_C[devnum] |= (0x01 << bit); | |
| } else { /* reset bit */ | |
| i8255_C[devnum] &= ~(0x01 << bit); | |
| } | |
| } | |
| } | |
| } | |
| return 0; | |
| } | |
| uint8 i8255a(t_bool io, uint8 data) | |
| { | |
| uint8 devnum; | |
| if ((devnum = i8255_get_dn()) != 0xFF) { | |
| if (io == 0) { /* read data port */ | |
| //return (i8255_unit[devnum].u4); | |
| return (i8255_A[devnum]); | |
| } else { /* write data port */ | |
| i8255_A[devnum] = data; | |
| if (DEBUG) | |
| sim_printf(" 8255-%d: Port A = %02X\n", devnum, data); | |
| } | |
| } | |
| return 0; | |
| } | |
| uint8 i8255b(t_bool io, uint8 data) | |
| { | |
| uint8 devnum; | |
| if ((devnum = i8255_get_dn()) != 0xFF) { | |
| if (io == 0) { /* read data port */ | |
| return (i8255_B[devnum]); | |
| } else { /* write data port */ | |
| i8255_B[devnum] = data; | |
| if (DEBUG) | |
| sim_printf(" 8255-%d: Port B = %02X\n", devnum, data); | |
| } | |
| } | |
| return 0; | |
| } | |
| uint8 i8255c(t_bool io, uint8 data) | |
| { | |
| uint8 devnum; | |
| if ((devnum = i8255_get_dn()) != 0xFF) { | |
| if (io == 0) { /* read data port */ | |
| return (i8255_C[devnum]); | |
| } else { /* write data port */ | |
| i8255_C[devnum] = data; | |
| if (DEBUG) | |
| sim_printf(" 8255-%d: Port C = %02X\n", devnum, data); | |
| } | |
| } | |
| return 0; | |
| } | |
| /* end of i8255.c */ |