| /* i8251.c: Intel 8251 UART 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 base and size. | |
| 24 Apr 15 -- Modified to use simh_debug | |
| NOTES: | |
| These functions support a simulated i8251 interface device on an iSBC. | |
| The device had one physical I/O port which could be connected | |
| to any serial I/O device that would connect to a current loop, | |
| RS232, or TTY interface. Available baud rates were jumper | |
| selectable for each port from 110 to 9600. | |
| All I/O is via programmed I/O. The i8251 has a status port | |
| and a data port. | |
| The simulated device does not support synchronous mode. The simulated device | |
| supports a select from I/O space and one address line. The data port is at the | |
| lower address and the status/command port is at the higher. | |
| A write to the status port can select some options for the device: | |
| Asynchronous Mode Instruction | |
| 7 6 5 4 3 2 1 0 | |
| +---+---+---+---+---+---+---+---+ | |
| | S2 S1 EP PEN L2 L1 B2 B1| | |
| +---+---+---+---+---+---+---+---+ | |
| Baud Rate Factor | |
| B2 0 1 0 1 | |
| B1 0 0 1 1 | |
| sync 1X 16X 64X | |
| mode | |
| Character Length | |
| L2 0 1 0 1 | |
| L1 0 0 1 1 | |
| 5 6 7 8 | |
| bits bits bits bits | |
| EP - A 1 in this bit position selects even parity. | |
| PEN - A 1 in this bit position enables parity. | |
| Number of Stop Bits | |
| S2 0 1 0 1 | |
| S1 0 0 1 1 | |
| invalid 1 1.5 2 | |
| bit bits bits | |
| Command Instruction Format | |
| 7 6 5 4 3 2 1 0 | |
| +---+---+---+---+---+---+---+---+ | |
| | EH IR RTS ER SBRK RxE DTR TxE| | |
| +---+---+---+---+---+---+---+---+ | |
| TxE - A 1 in this bit position enables transmit. | |
| DTR - A 1 in this bit position forces *DTR to zero. | |
| RxE - A 1 in this bit position enables receive. | |
| SBRK - A 1 in this bit position forces TxD to zero. | |
| ER - A 1 in this bit position resets the error bits | |
| RTS - A 1 in this bit position forces *RTS to zero. | |
| IR - A 1 in this bit position returns the 8251 to Mode Instruction Format. | |
| EH - A 1 in this bit position enables search for sync characters. | |
| A read of the status port gets the port status: | |
| Status Read Format | |
| 7 6 5 4 3 2 1 0 | |
| +---+---+---+---+---+---+---+---+ | |
| |DSR SD FE OE PE TxE RxR TxR| | |
| +---+---+---+---+---+---+---+---+ | |
| TxR - A 1 in this bit position signals transmit ready to receive a character. | |
| RxR - A 1 in this bit position signals receiver has a character. | |
| TxE - A 1 in this bit position signals transmitter has no more characters to transmit. | |
| PE - A 1 in this bit signals a parity error. | |
| OE - A 1 in this bit signals an transmit overrun error. | |
| FE - A 1 in this bit signals a framing error. | |
| SD - A 1 in this bit position returns the 8251 to Mode Instruction Format. | |
| DSR - A 1 in this bit position signals *DSR is at zero. | |
| A read from the data port gets the typed character, a write | |
| to the data port writes the character to the device. | |
| */ | |
| #include "system_defs.h" | |
| /* external globals */ | |
| extern uint16 port; | |
| #define UNIT_V_ANSI (UNIT_V_UF + 0) /* ANSI mode */ | |
| #define UNIT_ANSI (1 << UNIT_V_ANSI) | |
| #define TXR 0x01 | |
| #define RXR 0x02 | |
| #define TXE 0x04 | |
| #define SD 0x40 | |
| extern uint16 reg_dev(uint8 (*routine)(t_bool, uint8), uint16); | |
| /* function prototypes */ | |
| t_stat i8251_svc (UNIT *uptr); | |
| t_stat i8251_reset (DEVICE *dptr, uint16 base); | |
| void i8251_reset1(uint8 devnum); | |
| uint8 i8251_get_dn(void); | |
| uint8 i8251s(t_bool io, uint8 data); | |
| uint8 i8251d(t_bool io, uint8 data); | |
| /* globals */ | |
| int32 i8251_devnum = 0; //initially, no 8251 instances | |
| uint16 i8251_port[4]; //base port assigned to each 8251 instance | |
| /* i8251 Standard I/O Data Structures */ | |
| /* up to 1 i8251 devices */ | |
| UNIT i8251_unit = { | |
| { UDATA (&i8251_svc, 0, 0), KBD_POLL_WAIT }, | |
| { UDATA (&i8251_svc, 0, 0), KBD_POLL_WAIT }, | |
| { UDATA (&i8251_svc, 0, 0), KBD_POLL_WAIT }, | |
| { UDATA (&i8251_svc, 0, 0), KBD_POLL_WAIT } | |
| }; | |
| REG i8251_reg[4] = { | |
| { HRDATA (DATA0, i8251_unit[0].buf, 8) }, | |
| { HRDATA (STAT0, i8251_unit[0].u3, 8) }, | |
| { HRDATA (MODE0, i8251_unit[0].u4, 8) }, | |
| { HRDATA (CMD0, i8251_unit[0].u5, 8) }, | |
| { HRDATA (DATA1, i8251_unit[1].buf, 8) }, | |
| { HRDATA (STAT1, i8251_unit[1].u3, 8) }, | |
| { HRDATA (MODE1, i8251_unit[1].u4, 8) }, | |
| { HRDATA (CMD1, i8251_unit[1].u5, 8) }, | |
| { HRDATA (DATA2, i8251_unit[2].buf, 8) }, | |
| { HRDATA (STAT2, i8251_unit[2].u3, 8) }, | |
| { HRDATA (MODE2, i8251_unit[2].u4, 8) }, | |
| { HRDATA (CMD2, i8251_unit[2].u5, 8) }, | |
| { HRDATA (DATA3, i8251_unit[3].buf, 8) }, | |
| { HRDATA (STAT3, i8251_unit[3].u3, 8) }, | |
| { HRDATA (MOD3E, i8251_unit[3].u4, 8) }, | |
| { HRDATA (CMD3, i8251_unit[3].u5, 8) }, | |
| { NULL } | |
| }; | |
| DEBTAB i8251_debug[] = { | |
| { "ALL", DEBUG_all }, | |
| { "FLOW", DEBUG_flow }, | |
| { "READ", DEBUG_read }, | |
| { "WRITE", DEBUG_write }, | |
| { "XACK", DEBUG_xack }, | |
| { "LEV1", DEBUG_level1 }, | |
| { "LEV2", DEBUG_level2 }, | |
| { NULL } | |
| }; | |
| MTAB i8251_mod[] = { | |
| { UNIT_ANSI, 0, "TTY", "TTY", NULL }, | |
| { UNIT_ANSI, UNIT_ANSI, "ANSI", "ANSI", NULL }, | |
| { 0 } | |
| }; | |
| /* address width is set to 16 bits to use devices in 8086/8088 implementations */ | |
| DEVICE i8251_dev = { | |
| "8251", //name | |
| i8251_unit, //units | |
| i8251_reg, //registers | |
| i8251_mod, //modifiers | |
| 1, //numunits | |
| 16, //aradix | |
| 16, //awidth | |
| 1, //aincr | |
| 16, //dradix | |
| 8, //dwidth | |
| NULL, //examine | |
| NULL, //deposit | |
| // &i8251_reset, //reset | |
| NULL, //reset | |
| NULL, //boot | |
| NULL, //attach | |
| NULL, //detach | |
| NULL, //ctxt | |
| 0, //flags | |
| 0, //dctrl | |
| i8251_debug, //debflags | |
| NULL, //msize | |
| NULL //lname | |
| }; | |
| /* Service routines to handle simulator functions */ | |
| /* i8251_svc - actually gets char & places in buffer */ | |
| t_stat i8251_svc (UNIT *uptr) | |
| { | |
| int32 temp; | |
| sim_activate (&i8251_unit, i8251_unit.wait); /* continue poll */ | |
| if ((temp = sim_poll_kbd ()) < SCPE_KFLAG) | |
| return temp; /* no char or error? */ | |
| i8251_unit.buf = temp & 0xFF; /* Save char */ | |
| i8251_unit.u3 |= RXR; /* Set status */ | |
| /* Do any special character handling here */ | |
| i8251_unit.pos++; | |
| return SCPE_OK; | |
| } | |
| /* Reset routine */ | |
| t_stat i8251_reset (DEVICE *dptr, uint16 base) | |
| { | |
| if (i8251_devnum >= I8251_NUM) { | |
| sim_printf("8251_reset: too many devices!\n"); | |
| return 0; | |
| } | |
| i8251_port[i8251_devnum] = reg_dev(i8251d, base); | |
| reg_dev(i8251s, base + 1); | |
| i8251_reset1(i8251_devnum); | |
| sim_printf(" 8251-%d: Registered at %04X\n", i8251_devnum, base); | |
| sim_activate (&i8251_unit[i8251_devnum], i8251_unit[i8251_devnum].wait); /* activate unit */ | |
| i8259_devnum++; | |
| return SCPE_OK; | |
| } | |
| void i8251_reset1(uint8 devnum) | |
| { | |
| i8251_unit.u3 = TXR + TXE; /* status */ | |
| i8251_unit.u4 = 0; /* mode instruction */ | |
| i8251_unit.u5 = 0; /* command instruction */ | |
| i8251_unit.u6 = 0; | |
| i8251_unit.buf = 0; | |
| i8251_unit.pos = 0; | |
| sim_printf(" 8251-%d: Reset\n", devnum); | |
| } | |
| uint8 i8251_get_dn(void) | |
| { | |
| int i; | |
| for (i=0; i<I8251_NUM; i++) | |
| if (port >=i8251_port[i] && port <= i8251_port[i] + 1) | |
| return i; | |
| sim_printf("i8251_get_dn: port %03X not in 8251 device table\n", port); | |
| return 0xFF; | |
| } | |
| /* I/O instruction handlers, called from the CPU module when an | |
| IN or OUT instruction is issued. | |
| */ | |
| uint8 i8251s(t_bool io, uint8 data) | |
| { | |
| uint8 devnum; | |
| if ((devnum = i8259_get_dn()) != 0xFF) { | |
| if (io == 0) { /* read status port */ | |
| return i8251_unit[devnum].u3; | |
| } else { /* write status port */ | |
| if (i8251_unit[devnum].u6) { /* if mode, set cmd */ | |
| i8251_unit[devnum].u5 = data; | |
| sim_printf(" 8251-%d: Command Instruction=%02X\n", devnum, data); | |
| if (data & SD) /* reset port! */ | |
| i8251_reset1(devnum); | |
| } else { /* set mode */ | |
| i8251_unit[devnum].u4 = data; | |
| sim_printf(" 8251-%d: Mode Instruction=%02X\n", devnum, data); | |
| i8251_unit[devnum].u6 = 1; /* set cmd received */ | |
| } | |
| } | |
| } | |
| return 0; | |
| } | |
| uint8 i8251d(t_bool io, uint8 data) | |
| { | |
| uint8 devnum; | |
| if ((devnum = i8259_get_dn()) != 0xFF) { | |
| if (io == 0) { /* read data port */ | |
| i8251_unit[devnum].u3 &= ~RXR; | |
| return (i8251_unit[devnum].buf); | |
| } else { /* write data port */ | |
| sim_putchar(data); | |
| } | |
| } | |
| return 0; | |
| } | |
| /* end of i8251.c */ |