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/* 3b2_iu.h: SCN2681A Dual UART Header
Copyright (c) 2017, Seth J. Morabito
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 THE AUTHORS OR COPYRIGHT HOLDERS
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 the author shall
not be used in advertising or otherwise to promote the sale, use or
other dealings in this Software without prior written authorization
from the author.
*/
#ifndef __3B2_IU_H__
#define __3B2_IU_H__
#include "3b2_defs.h"
#include "3b2_sysdev.h"
#define CMD_ERX 0x01 /* Enable receiver */
#define CMD_DRX 0x02 /* Disable receiver */
#define CMD_ETX 0x04 /* Enable transmitter */
#define CMD_DTX 0x08 /* Disable transmitter */
#define CMD_MISC_SHIFT 4 /* Command */
#define CMD_MISC_MASK 0x7
#define STS_RXR 0x01 /* Receiver ready */
#define STS_FFL 0x02 /* FIFO full */
#define STS_TXR 0x04 /* Transmitter ready */
#define STS_TXE 0x08 /* Transmitter empty */
#define STS_OER 0x10 /* Overrun error */
#define STS_PER 0x20 /* Parity error */
#define STS_FER 0x40 /* Framing error */
#define STS_RXB 0x80 /* Received break */
#define ISTS_TAI 0x01 /* Transmitter ready A */
#define ISTS_RAI 0x02 /* Receiver ready A */
#define ISTS_CBA 0x04 /* Change in break A */
#define ISTS_CRI 0x08 /* Counter ready */
#define ISTS_TBI 0x10 /* Transmitter ready B */
#define ISTS_RBI 0x20 /* Receiver ready B */
#define ISTS_CBB 0x40 /* Change in break B */
#define ISTS_IPC 0x80 /* Interrupt port change */
#define MODE_V_CHM 6 /* Channel mode */
#define MODE_M_CHM 0x3
/* Used by the DMAC */
#define IUA_DATA_REG 3
#define IUB_DATA_REG 11
/* Registers - Read */
#define SRA 1
#define RHRA 3
#define IPCR 4
#define ISR 5
#define CTU 6
#define CTL 7
#define SRB 9
#define RHRB 11
#define INPRT 13 /* Input port data */
#define START_CTR 14
#define STOP_CTR 15
/* Registers - Write */
#define CSRA 1
#define CRA 2
#define THRA 3
#define ACR 4
#define IMR 5
#define CTUR 6
#define CTLR 7
#define CSRB 9
#define CRB 10
#define THRB 11
#define OPCR 13
#define SOPR 14
#define ROPR 15
/* Registers - R/W */
#define MR12A 0
#define MR12B 8
/* Port configuration */
#define TX_EN 1
#define RX_EN 2
#define UM_CTR_EXT 0
#define UM_CTR_TXCA 1
#define UM_CTR_TXCB 2
#define UM_CTR_DIV16 3
#define UM_TMR_EXT 4
#define UM_TMR_EXT16 5
#define UM_TMR_XTL 6
#define UM_TMR_XTL16 7
#define UM_MASK 0x70
#define UM_SHIFT 4
/* IMR bits */
#define IMR_TXRA 0x01
#define IMR_RXRA 0x02
#define IMR_CTR 0x08
#define IMR_TXRB 0x10
#define IMR_RXRB 0x20
/* Power-off bit */
#define IU_KILLPWR 0x04
#define PORT_A 0
#define PORT_B 1
#define IU_MODE(x) ((x & UM_MASK) >> UM_SHIFT)
extern DEVICE tti_dev;
extern DEVICE tto_dev;
extern DEVICE contty_dev;
extern DEVICE iu_timer_dev;
#define IUBASE 0x49000
#define IUSIZE 0x100
/* The UART is driven by a 3.6864 MHz crystal. This is divided by 16
to clock the timer. (One peculiarity: 3.6864 MHz /16 is 230400 Hz,
but the SVR3 source code claims the /16 clock is actually 230525
Hz. So, we'll go with 230525 Hz until proven otherwise.)
UART clock period = 4338ns
System clock period = 100ns
That means the system ticks 43.3792 times for every one tick of the
UART clock.
But this is a simulated system, where each simulator step is
CYCLES_PER_INST long. So we take that into account.
*/
#define IU_TIMER_STP 4.33792
#define IU_BUF_SIZE 3
#define IU_DCDA 0x01
#define IU_DCDB 0x02
#define IU_DTRA 0x01
#define IU_DTRB 0x02
typedef struct iu_port {
uint8 stat; /* Port Status */
uint8 cmd; /* Command */
uint8 mode[2]; /* Two mode buffers */
uint8 modep; /* Point to mode[0] or mode[1] */
uint8 conf; /* Configuration bits */
uint8 txbuf; /* Transmit Holding Register */
uint8 rxbuf[IU_BUF_SIZE]; /* Receive Holding Register (3 bytes) */
uint8 w_p; /* Buffer Write Pointer */
uint8 r_p; /* Buffer Read Pointer */
t_bool drq; /* DRQ enabled */
} IU_PORT;
typedef struct iu_state {
uint8 istat; /* Interrupt Status */
uint8 imr; /* Interrupt Mask Register */
uint8 acr;
uint8 opcr; /* Output Port Configuration */
uint8 inprt; /* Input Port Data */
uint8 ipcr; /* Input Port Change Register */
} IU_STATE;
typedef struct iu_timer_state {
uint16 c_set;
t_bool c_en;
} IU_TIMER_STATE;
extern IU_PORT iu_console;
extern IU_PORT iu_contty;
/* Function prototypes */
t_stat contty_attach(UNIT *uptr, CONST char *cptr);
t_stat contty_detach(UNIT *uptr);
t_stat tti_reset(DEVICE *dptr);
t_stat contty_reset(DEVICE *dptr);
t_stat iu_timer_reset(DEVICE *dptr);
t_stat iu_svc_tti(UNIT *uptr);
t_stat iu_svc_tto(UNIT *uptr);
t_stat iu_svc_contty_rcv(UNIT *uptr);
t_stat iu_svc_contty_xmt(UNIT *uptr);
t_stat iu_svc_timer(UNIT *uptr);
uint32 iu_read(uint32 pa, size_t size);
void iu_write(uint32 pa, uint32 val, size_t size);
void iua_drq_handled();
void iub_drq_handled();
void iu_txrdy_a_irq();
void iu_txrdy_b_irq();
static SIM_INLINE void iu_tx(uint8 portno, uint8 val);
static SIM_INLINE void iu_w_buf(uint8 portno, uint8 val);
static SIM_INLINE void iu_w_cmd(uint8 portno, uint8 val);
static SIM_INLINE void iu_update_rxi(uint8 c);
static SIM_INLINE void iu_update_txi();
#endif