| /* 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 (PIOS) |
| and three data ports (PIOA, PIOB, and PIOC). |
| |
| 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 */ |
| |
| /* 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 i8255s(t_bool io, uint8 data); |
| uint8 i8255a(t_bool io, uint8 data); |
| uint8 i8255b(t_bool io, uint8 data); |
| uint8 i8255c(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 = { |
| "8255", //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_reset, //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 i8255_unit[devnum].u3; |
| } else { /* write status port */ |
| if (data & 0x80) { /* mode instruction */ |
| i8255_unit[devnum].u3 = data; |
| 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; |
| 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; |
| 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; |
| sim_printf(" 8255-%d: Port C = %02X\n", devnum, data); |
| } |
| } |
| return 0; |
| } |
| |
| /* end of i8255.c */ |