Home | History | Annotate | Line # | Download | only in ic
z8530reg.h revision 1.1
      1 /*	$NetBSD: z8530reg.h,v 1.1 1995/04/11 02:29:25 mycroft Exp $ */
      2 
      3 /*
      4  * Copyright (c) 1992, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This software was developed by the Computer Systems Engineering group
      8  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
      9  * contributed to Berkeley.
     10  *
     11  * All advertising materials mentioning features or use of this software
     12  * must display the following acknowledgement:
     13  *	This product includes software developed by the University of
     14  *	California, Lawrence Berkeley Laboratory.
     15  *
     16  * Redistribution and use in source and binary forms, with or without
     17  * modification, are permitted provided that the following conditions
     18  * are met:
     19  * 1. Redistributions of source code must retain the above copyright
     20  *    notice, this list of conditions and the following disclaimer.
     21  * 2. Redistributions in binary form must reproduce the above copyright
     22  *    notice, this list of conditions and the following disclaimer in the
     23  *    documentation and/or other materials provided with the distribution.
     24  * 3. All advertising materials mentioning features or use of this software
     25  *    must display the following acknowledgement:
     26  *	This product includes software developed by the University of
     27  *	California, Berkeley and its contributors.
     28  * 4. Neither the name of the University nor the names of its contributors
     29  *    may be used to endorse or promote products derived from this software
     30  *    without specific prior written permission.
     31  *
     32  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     33  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     34  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     35  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     36  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     37  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     38  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     39  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     40  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     41  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     42  * SUCH DAMAGE.
     43  *
     44  *	@(#)zsreg.h	8.1 (Berkeley) 6/11/93
     45  */
     46 
     47 /*
     48  * Zilog SCC registers, as implemented on the Sun-4c.
     49  *
     50  * Each Z8530 implements two channels (called `a' and `b').
     51  *
     52  * The damnable chip was designed to fit on Z80 I/O ports, and thus
     53  * has everything multiplexed out the wazoo.  We have to select
     54  * a register, then read or write the register, and so on.  Worse,
     55  * the parameter bits are scattered all over the register space.
     56  * This thing is full of `miscellaneous' control registers.
     57  *
     58  * Worse yet, the registers have incompatible functions on read
     59  * and write operations.  We describe the registers below according
     60  * to whether they are `read registers' (RR) or `write registers' (WR).
     61  * As if this were not enough, some of the channel B status bits show
     62  * up in channel A, and vice versa.  The blasted thing shares write
     63  * registers 2 and 9 across both channels, and reads registers 2 and 3
     64  * differently for the two channels.  We can, however, ignore this much
     65  * of the time.
     66  */
     67 #ifndef LOCORE
     68 struct zschan {
     69 	u_char	zc_csr;		/* control and status, and indirect access */
     70 	u_char	zc_xxx0;
     71 	u_char	zc_data;	/* data */
     72 	u_char	zc_xxx1;
     73 };
     74 
     75 /*
     76  * N.B.: the keyboard is channel 1, the mouse channel 0; ttyb is 1, ttya
     77  * is 0.  In other words, the things are BACKWARDS.
     78  */
     79 struct zsdevice {
     80 	struct	zschan zs_chan[2];	/* channel A = 1, B = 0 */
     81 };
     82 
     83 #define	CHAN_A	1
     84 #define	CHAN_B	0
     85 #endif
     86 
     87 /*
     88  * Some of the names in this files were chosen to make the hsis driver
     89  * work unchanged (which means that they will match some in SunOS).
     90  *
     91  * `S.C.' stands for Special Condition, which is any of these:
     92  *	receiver overrun	(aka silo overflow)
     93  *	framing error		(missing stop bit, etc)
     94  *	end of frame		(in synchronous modes)
     95  *	parity error		(when `parity error is S.C.' is set)
     96  */
     97 
     98 /*
     99  * Registers with only a single `numeric value' get a name.
    100  * Other registers hold bits and are only numbered; the bit
    101  * definitions imply the register number (see below).
    102  *
    103  * We never use the receive and transmit data registers as
    104  * indirects (choosing instead the zc_data register), so they
    105  * are not defined here.
    106  */
    107 #define	ZSRR_IVEC	2	/* interrupt vector (channel 0) */
    108 #define	ZSRR_IPEND	3	/* interrupt pending (ch. 0 only) */
    109 #define	ZSRR_BAUDLO	12	/* baud rate generator (low half) */
    110 #define	ZSRR_BAUDHI	13	/* baud rate generator (high half) */
    111 
    112 #define	ZSWR_IVEC	2	/* interrupt vector (shared) */
    113 #define	ZSWR_TXSYNC	6	/* sync transmit char (monosync mode) */
    114 #define	ZSWR_RXSYNC	7	/* sync receive char (monosync mode) */
    115 #define	ZSWR_SYNCLO	6	/* sync low byte (bisync mode) */
    116 #define	ZSWR_SYNCHI	7	/* sync high byte (bisync mode) */
    117 #define	ZSWR_SDLC_ADDR	6	/* SDLC address (SDLC mode) */
    118 #define	ZSWR_SDLC_FLAG	7	/* SDLC flag 0x7E (SDLC mode) */
    119 #define	ZSWR_BAUDLO	12	/* baud rate generator (low half) */
    120 #define	ZSWR_BAUDHI	13	/* baud rate generator (high half) */
    121 
    122 /*
    123  * Registers 0 through 7 may be written with any one of the 8 command
    124  * modifiers, and/or any one of the 4 reset modifiers, defined below.
    125  * To write registers 8 through 15, however, the command modifier must
    126  * always be `point high'.  Rather than track this bizzareness all over
    127  * the driver, we try to avoid using any modifiers, ever (but they are
    128  * defined here if you want them).
    129  */
    130 #define	ZSM_RESET_TXUEOM	0xc0	/* reset xmit underrun / eom latch */
    131 #define	ZSM_RESET_TXCRC		0x80	/* reset xmit crc generator */
    132 #define	ZSM_RESET_RXCRC		0x40	/* reset recv crc checker */
    133 #define	ZSM_NULL		0x00	/* nothing special */
    134 
    135 #define	ZSM_RESET_IUS		0x38	/* reset interrupt under service */
    136 #define	ZSM_RESET_ERR		0x30	/* reset error cond */
    137 #define	ZSM_RESET_TXINT		0x28	/* reset xmit interrupt pending */
    138 #define	ZSM_EI_NEXTRXC		0x20	/* enable int. on next rcvd char */
    139 #define	ZSM_SEND_ABORT		0x18	/* send abort (SDLC) */
    140 #define	ZSM_RESET_STINT		0x10	/* reset external/status interrupt */
    141 #define	ZSM_POINTHIGH		0x08	/* `point high' (use r8-r15) */
    142 #define	ZSM_NULL		0x00	/* nothing special */
    143 
    144 /*
    145  * Commands for Write Register 0 (`Command Register').
    146  * These are just the command modifiers or'ed with register number 0
    147  * (which of course equals the command modifier).
    148  */
    149 #define	ZSWR0_RESET_EOM		ZSM_RESET_TXUEOM
    150 #define	ZSWR0_RESET_TXCRC	ZSM_RESET_TXCRC
    151 #define	ZSWR0_RESET_RXCRC	ZSM_RESET_RXCRC
    152 #define	ZSWR0_CLR_INTR		ZSM_RESET_IUS
    153 #define	ZSWR0_RESET_ERRORS	ZSM_RESET_ERR
    154 #define	ZSWR0_EI_NEXTRXC	ZSM_EI_NEXTRXC
    155 #define	ZSWR0_SEND_ABORT	ZSM_SEND_ABORT
    156 #define	ZSWR0_RESET_STATUS	ZSM_RESET_STINT
    157 #define	ZSWR0_RESET_TXINT	ZSM_RESET_TXINT
    158 
    159 /*
    160  * Bits in Write Register 1 (`Transmit/Receive Interrupt and Data
    161  * Transfer Mode Definition').  Note that bits 3 and 4 are taken together
    162  * as a single unit, and bits 5 and 6 are useful only if bit 7 is set.
    163  */
    164 #define	ZSWR1_REQ_WAIT		0x80	/* WAIT*-REQ* pin gives WAIT* */
    165 #define	ZSWR1_REQ_REQ		0xc0	/* WAIT*-REQ* pin gives REQ* */
    166 #define	ZSWR1_REQ_TX		0x00	/* WAIT*-REQ* pin follows xmit buf */
    167 #define	ZSWR1_REQ_RX		0x20	/* WAIT*-REQ* pin follows recv buf */
    168 
    169 #define	ZSWR1_RIE_NONE		0x00	/* disable rxint entirely */
    170 #define	ZSWR1_RIE_FIRST		0x08	/* rxint on first char & on S.C. */
    171 #define	ZSWR1_RIE		0x10	/* rxint per char & on S.C. */
    172 #define	ZSWR1_RIE_SPECIAL_ONLY	0x18	/* rxint on S.C. only */
    173 
    174 #define	ZSWR1_PE_SC		0x04	/* parity error is special condition */
    175 #define	ZSWR1_TIE		0x02	/* transmit interrupt enable */
    176 #define	ZSWR1_SIE		0x01	/* external/status interrupt enable */
    177 
    178 /* HSIS compat */
    179 #define	ZSWR1_REQ_ENABLE	(ZSWR1_REQ_WAIT | ZSWR1_REQ_TX)
    180 
    181 /*
    182  * Bits in Write Register 3 (`Receive Parameters and Control').
    183  * Bits 7 and 6 are taken as a unit.  Note that the receive bits
    184  * per character ordering is insane.
    185  *
    186  * Here `hardware flow control' means CTS enables the transmitter
    187  * and DCD enables the receiver.  The latter is neither interesting
    188  * nor useful, and gets in our way, making it almost unusable.
    189  */
    190 #define	ZSWR3_RX_5		0x00	/* receive 5 bits per char */
    191 #define	ZSWR3_RX_7		0x40	/* receive 7 bits per char */
    192 #define	ZSWR3_RX_6		0x80	/* receive 6 bits per char */
    193 #define	ZSWR3_RX_8		0xc0	/* receive 8 bits per char */
    194 
    195 #define	ZSWR3_HFC		0x20	/* hardware flow control */
    196 #define	ZSWR3_HUNT		0x10	/* enter hunt mode */
    197 #define	ZSWR3_RXCRC_ENABLE	0x08	/* enable recv crc calculation */
    198 #define	ZSWR3_ADDR_SEARCH_MODE	0x04	/* address search mode (SDLC only) */
    199 #define	ZSWR3_SYNC_LOAD_INH	0x02	/* sync character load inhibit */
    200 #define	ZSWR3_RX_ENABLE		0x01	/* receiver enable */
    201 
    202 /*
    203  * Bits in Write Register 4 (`Transmit/Receive Miscellaneous Parameters
    204  * and Modes').  Bits 7&6, 5&4, and 3&2 are taken as units.
    205  */
    206 #define	ZSWR4_CLK_X1		0x00	/* clock divisor = 1 */
    207 #define	ZSWR4_CLK_X16		0x40	/* clock divisor = 16 */
    208 #define	ZSWR4_CLK_X32		0x80	/* clock divisor = 32 */
    209 #define	ZSWR4_CLK_X64		0xc0	/* clock divisor = 64 */
    210 
    211 #define	ZSWR4_MONOSYNC		0x00	/* 8 bit sync char (sync only) */
    212 #define	ZSWR4_BISYNC		0x10	/* 16 bit sync char (sync only) */
    213 #define	ZSWR4_SDLC		0x20	/* SDLC mode */
    214 #define	ZSWR4_EXTSYNC		0x30	/* external sync mode */
    215 
    216 #define	ZSWR4_SYNCMODE		0x00	/* one of the above sync modes */
    217 #define	ZSWR4_ONESB		0x04	/* 1 stop bit */
    218 #define	ZSWR4_1P5SB		0x08	/* 1.5 stop bits (clk cannot be 1x) */
    219 #define	ZSWR4_TWOSB		0x0c	/* 2 stop bits */
    220 
    221 #define	ZSWR4_EVENP		0x02	/* check for even parity */
    222 #define	ZSWR4_PARENB		0x01	/* enable parity checking */
    223 
    224 /*
    225  * Bits in Write Register 5 (`Transmit Parameter and Controls').
    226  * Bits 6 and 5 are taken as a unit; the ordering is, as with RX
    227  * bits per char, not sensible.
    228  */
    229 #define	ZSWR5_DTR		0x80	/* assert (set to -12V) DTR */
    230 
    231 #define	ZSWR5_TX_5		0x00	/* transmit 5 or fewer bits */
    232 #define	ZSWR5_TX_7		0x20	/* transmit 7 bits */
    233 #define	ZSWR5_TX_6		0x40	/* transmit 6 bits */
    234 #define	ZSWR5_TX_8		0x60	/* transmit 8 bits */
    235 
    236 #define	ZSWR5_BREAK		0x10	/* send break (continuous 0s) */
    237 #define	ZSWR5_TX_ENABLE		0x08	/* enable transmitter */
    238 #define	ZSWR5_CRC16		0x04	/* use CRC16 (off => use SDLC) */
    239 #define	ZSWR5_RTS		0x02	/* assert RTS */
    240 #define	ZSWR5_TXCRC_ENABLE	0x01	/* enable xmit crc calculation */
    241 
    242 #ifdef not_done_here
    243 /*
    244  * Bits in Write Register 7 when the chip is in SDLC mode.
    245  */
    246 #define	ZSWR7_SDLCFLAG		0x7e	/* this value makes SDLC mode work */
    247 #endif
    248 
    249 /*
    250  * Bits in Write Register 9 (`Master Interrupt Control').  Bits 7 & 6
    251  * are taken as a unit and indicate the type of reset; 00 means no reset
    252  * (and is not defined here).
    253  */
    254 #define	ZSWR9_HARD_RESET	0xc0	/* force hardware reset */
    255 #define	ZSWR9_A_RESET		0x80	/* reset channel A (0) */
    256 #define	ZSWR9_B_RESET		0x40	/* reset channel B (1) */
    257 			/*	0x20	   unused */
    258 
    259 #define	ZSWR9_STATUS_HIGH	0x10	/* status in high bits of intr vec */
    260 #define	ZSWR9_MASTER_IE		0x08	/* master interrupt enable */
    261 #define	ZSWR9_DLC		0x04	/* disable lower chain */
    262 #define	ZSWR9_NO_VECTOR		0x02	/* no vector */
    263 #define	ZSWR9_VECTOR_INCL_STAT	0x01	/* vector includes status */
    264 
    265 /*
    266  * Bits in Write Register 10 (`Miscellaneous Transmitter/Receiver Control
    267  * Bits').  Bits 6 & 5 are taken as a unit, and some of the bits are
    268  * meaningful only in certain modes.  Bleah.
    269  */
    270 #define	ZSWR10_PRESET_ONES	0x80	/* preset CRC to all 1 (else all 0) */
    271 
    272 #define	ZSWR10_NRZ		0x00	/* NRZ encoding */
    273 #define	ZSWR10_NRZI		0x20	/* NRZI encoding */
    274 #define	ZSWR10_FM1		0x40	/* FM1 encoding */
    275 #define	ZSWR10_FM0		0x60	/* FM0 encoding */
    276 
    277 #define	ZSWR10_GA_ON_POLL	0x10	/* go active on poll (loop mode) */
    278 #define	ZSWR10_MARK_IDLE	0x08	/* all 1s (vs flag) when idle (SDLC) */
    279 #define	ZSWR10_ABORT_ON_UNDERRUN 0x4	/* abort on xmit underrun (SDLC) */
    280 #define	ZSWR10_LOOP_MODE	0x02	/* loop mode (SDLC) */
    281 #define	ZSWR10_6_BIT_SYNC	0x01	/* 6 bits per sync char (sync modes) */
    282 
    283 /*
    284  * Bits in Write Register 11 (`Clock Mode Control').  Bits 6&5, 4&3, and
    285  * 1&0 are taken as units.  Various bits depend on other bits in complex
    286  * ways; see the Zilog manual.
    287  */
    288 #define	ZSWR11_XTAL		0x80	/* have xtal between RTxC* and SYNC* */
    289 					/* (else have TTL oscil. on RTxC*) */
    290 #define	ZSWR11_RXCLK_RTXC	0x00	/* recv clock taken from TRxC* pin */
    291 #define	ZSWR11_RXCLK_TRXC	0x20	/* recv clock taken from TRxC* pin */
    292 #define	ZSWR11_RXCLK_BAUD	0x40	/* recv clock taken from BRG */
    293 #define	ZSWR11_RXCLK_DPLL	0x60	/* recv clock taken from DPLL */
    294 
    295 #define	ZSWR11_TXCLK_RTXC	0x00	/* xmit clock taken from TRxC* pin */
    296 #define	ZSWR11_TXCLK_TRXC	0x08	/* xmit clock taken from RTxC* pin */
    297 #define	ZSWR11_TXCLK_BAUD	0x10	/* xmit clock taken from BRG */
    298 #define	ZSWR11_TXCLK_DPLL	0x18	/* xmit clock taken from DPLL */
    299 
    300 #define	ZSWR11_TRXC_OUT_ENA	0x04	/* TRxC* pin will be an output */
    301 					/* (unless it is being used above) */
    302 #define	ZSWR11_TRXC_XTAL	0x00	/* TRxC output from xtal oscillator */
    303 #define	ZSWR11_TRXC_XMIT	0x01	/* TRxC output from xmit clock */
    304 #define	ZSWR11_TRXC_BAUD	0x02	/* TRxC output from BRG */
    305 #define	ZSWR11_TRXC_DPLL	0x03	/* TRxC output from DPLL */
    306 
    307 /*
    308  * Formula for Write Registers 12 and 13 (`Lower Byte of Baud Rate
    309  * Generator Time Constant' and `Upper Byte of ...').  Inputs:
    310  *
    311  *	f	BRG input clock frequency (in Hz) AFTER division
    312  *		by 1, 16, 32, or 64 (per clock divisor in WR4)
    313  *	bps	desired rate in bits per second (9600, etc)
    314  *
    315  * We want
    316  *
    317  *	  f
    318  *	----- + 0.5 - 2
    319  *	2 bps
    320  *
    321  * rounded down to an integer.  This can be computed entirely
    322  * in integer arithemtic as:
    323  *
    324  *	f + bps
    325  *	------- - 2
    326  *	 2 bps
    327  */
    328 #define	BPS_TO_TCONST(f, bps)	((((f) + (bps)) / (2 * (bps))) - 2)
    329 
    330 /* inverse of above: given a BRG Time Constant, return Bits Per Second */
    331 #define	TCONST_TO_BPS(f, tc)	((f) / 2 / ((tc) + 2))
    332 
    333 /*
    334  * Bits in Write Register 14 (`Miscellaneous Control Bits').
    335  * Bits 7 through 5 are taken as a unit and make up a `DPLL command'.
    336  */
    337 #define	ZSWR14_DPLL_NOOP	0x00	/* leave DPLL alone */
    338 #define	ZSWR14_DPLL_SEARCH	0x20	/* enter search mode */
    339 #define	ZSWR14_DPLL_RESET_CM	0x40	/* reset `clock missing' in RR10 */
    340 #define	ZSWR14_DPLL_DISABLE	0x60	/* disable DPLL (continuous search) */
    341 #define	ZSWR14_DPLL_SRC_BAUD	0x80	/* set DPLL src = BRG */
    342 #define	ZSWR14_DPLL_SRC_RTXC	0xa0	/* set DPLL src = RTxC* or xtal osc */
    343 #define	ZSWR14_DPLL_FM		0xc0	/* operate in FM mode */
    344 #define	ZSWR14_DPLL_NRZI	0xe0	/* operate in NRZI mode */
    345 
    346 #define	ZSWR14_LOCAL_LOOPBACK	0x10	/* set local loopback mode */
    347 #define	ZSWR14_AUTO_ECHO	0x08	/* set auto echo mode */
    348 #define	ZSWR14_DTR_REQ		0x04	/* DTR*/REQ* pin gives REQ* */
    349 #define	ZSWR14_BAUD_FROM_PCLK	0x02	/* BRG clock taken from PCLK */
    350 					/* (else from RTxC* pin or xtal osc) */
    351 #define	ZSWR14_BAUD_ENA		0x01	/* enable BRG countdown */
    352 
    353 /*
    354  * Bits in Write Register 15 (`External/Status Interrupt Control').
    355  * Most of these cause status interrupts whenever the corresponding
    356  * bit or pin changes state (i.e., any rising or falling edge).
    357  */
    358 #define	ZSWR15_BREAK_IE		0x80	/* enable break/abort status int */
    359 #define	ZSWR15_TXUEOM_IE	0x40	/* enable TX underrun/EOM status int */
    360 #define	ZSWR15_CTS_IE		0x20	/* enable CTS* pin status int */
    361 #define	ZSWR15_SYNCHUNT_IE	0x10	/* enable SYNC* pin/hunt status int */
    362 #define	ZSWR15_DCD_IE		0x08	/* enable DCD* pin status int */
    363 			/*	0x04	   unused, must be zero */
    364 #define	ZSWR15_ZERO_COUNT_IE	0x02	/* enable BRG-counter = 0 status int */
    365 			/*	0x01	   unused, must be zero */
    366 
    367 /*
    368  * Bits in Read Register 0 (`Transmit/Receive Buffer Status and External
    369  * Status').
    370  */
    371 #define	ZSRR0_BREAK		0x80	/* break/abort detected */
    372 #define	ZSRR0_TXUNDER		0x40	/* transmit underrun/EOM (sync) */
    373 #define	ZSRR0_CTS		0x20	/* clear to send */
    374 #define	ZSRR0_SYNC_HUNT		0x10	/* sync/hunt (sync mode) */
    375 #define	ZSRR0_DCD		0x08	/* data carrier detect */
    376 #define	ZSRR0_TX_READY		0x04	/* transmit buffer empty */
    377 #define	ZSRR0_ZERO_COUNT	0x02	/* zero count in baud clock */
    378 #define	ZSRR0_RX_READY		0x01	/* received character ready */
    379 
    380 /*
    381  * Bits in Read Register 1 (the Zilog book does not name this one).
    382  */
    383 #define	ZSRR1_EOF		0x80	/* end of frame (SDLC mode) */
    384 #define	ZSRR1_FE		0x40	/* CRC/framing error */
    385 #define	ZSRR1_DO		0x20	/* data (receiver) overrun */
    386 #define	ZSRR1_PE		0x10	/* parity error */
    387 #define	ZSRR1_RC0		0x08	/* residue code 0 (SDLC mode) */
    388 #define	ZSRR1_RC1		0x04	/* residue code 1 (SDLC mode) */
    389 #define	ZSRR1_RC2		0x02	/* residue code 2 (SDLC mode) */
    390 #define	ZSRR1_ALL_SENT		0x01	/* all chars out of xmitter (async) */
    391 
    392 /*
    393  * Read Register 2 in B channel contains status bits if VECTOR_INCL_STAT
    394  * is set.
    395  */
    396 
    397 /*
    398  * Bits in Read Register 3 (`Interrupt Pending').  Only channel A
    399  * has an RR3.
    400  */
    401 			/*	0x80	   unused, returned as 0 */
    402 			/*	0x40	   unused, returned as 0 */
    403 #define	ZSRR3_IP_A_RX		0x20	/* channel A recv int pending */
    404 #define	ZSRR3_IP_A_TX		0x10	/* channel A xmit int pending */
    405 #define	ZSRR3_IP_A_STAT		0x08	/* channel A status int pending */
    406 #define	ZSRR3_IP_B_RX		0x04	/* channel B recv int pending */
    407 #define	ZSRR3_IP_B_TX		0x02	/* channel B xmit int pending */
    408 #define	ZSRR3_IP_B_STAT		0x01	/* channel B status int pending */
    409 
    410 /*
    411  * Bits in Read Register 10 (`contains some miscellaneous status bits').
    412  */
    413 #define	ZSRR10_1_CLOCK_MISSING	0x80	/* 1 clock edge missing (FM mode) */
    414 #define	ZSRR10_2_CLOCKS_MISSING	0x40	/* 2 clock edges missing (FM mode) */
    415 			/*	0x20	   unused */
    416 #define	ZSRR10_LOOP_SENDING	0x10	/* xmitter controls loop (SDLC loop) */
    417 			/*	0x08	   unused */
    418 			/*	0x04	   unused */
    419 #define	ZSRR10_ON_LOOP		0x02	/* SCC is on loop (SDLC/X.21 modes) */
    420 
    421 /*
    422  * Bits in Read Register 15.  This register is one of the few that
    423  * simply reads back the corresponding Write Register.
    424  */
    425 #define	ZSRR15_BREAK_IE		0x80	/* break/abort status int enable */
    426 #define	ZSRR15_TXUEOM_IE	0x40	/* TX underrun/EOM status int enable */
    427 #define	ZSRR15_CTS_IE		0x20	/* CTS* pin status int enable */
    428 #define	ZSRR15_SYNCHUNT_IE	0x10	/* SYNC* pin/hunt status int enable */
    429 #define	ZSRR15_DCD_IE		0x08	/* DCD* pin status int enable */
    430 			/*	0x04	   unused, returned as zero */
    431 #define	ZSRR15_ZERO_COUNT_IE	0x02	/* BRG-counter = 0 status int enable */
    432 			/*	0x01	   unused, returned as zero */
    433