xref: /netbsd/sys/dev/ic/z8530reg.h (revision bf9ec67e)
1 /*	$NetBSD: z8530reg.h,v 1.9 1998/07/31 05:08:38 wrstuden 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  * This file also includes flags for the Z85C30 and Z85230 enhanced scc.
68  * The CMOS 8530 includes extra SDLC functionality, and is used in a
69  * number of Macs (often in the Z85C80, an 85C30 combined w/ a SCSI
70  * controller). -wrs
71  *
72  * Some of the names in this files were chosen to make the hsis driver
73  * work unchanged (which means that they will match some in SunOS).
74  *
75  * `S.C.' stands for Special Condition, which is any of these:
76  *	receiver overrun	(aka silo overflow)
77  *	framing error		(missing stop bit, etc)
78  *	end of frame		(in synchronous modes)
79  *	parity error		(when `parity error is S.C.' is set)
80  *
81  * Registers with only a single `numeric value' get a name.
82  * Other registers hold bits and are only numbered; the bit
83  * definitions imply the register number (see below).
84  *
85  * We never use the receive and transmit data registers as
86  * indirects (choosing instead the zc_data register), so they
87  * are not defined here.
88  */
89 #define	ZSRR_IVEC	2	/* interrupt vector (channel 0) */
90 #define	ZSRR_IPEND	3	/* interrupt pending (ch. 0 only) */
91 #define	ZSRR_TXSYNC	6	/* sync transmit char (monosync mode) */
92 #define	ZSRR_RXSYNC	7	/* sync receive char (monosync mode) */
93 #define	ZSRR_SYNCLO	6	/* sync low byte (bisync mode) */
94 #define	ZSRR_SYNCHI	7	/* sync high byte (bisync mode) */
95 #define	ZSRR_SDLC_ADDR	6	/* SDLC address (SDLC mode) */
96 #define	ZSRR_SDLC_FLAG	7	/* SDLC flag 0x7E (SDLC mode) */
97 #define	ZSRR_BAUDLO	12	/* baud rate generator (low half) */
98 #define	ZSRR_BAUDHI	13	/* baud rate generator (high half) */
99 #define	ZSRR_ENHANCED	14	/* read address of WR7' - yes, it's not 7!*/
100 
101 #define	ZSWR_IVEC	2	/* interrupt vector (shared) */
102 #define	ZSWR_TXSYNC	6	/* sync transmit char (monosync mode) */
103 #define	ZSWR_RXSYNC	7	/* sync receive char (monosync mode) */
104 #define	ZSWR_SYNCLO	6	/* sync low byte (bisync mode) */
105 #define	ZSWR_SYNCHI	7	/* sync high byte (bisync mode) */
106 #define	ZSWR_SDLC_ADDR	6	/* SDLC address (SDLC mode) */
107 #define	ZSWR_SDLC_FLAG	7	/* SDLC flag 0x7E (SDLC mode) */
108 #define	ZSWR_BAUDLO	12	/* baud rate generator (low half) */
109 #define	ZSWR_BAUDHI	13	/* baud rate generator (high half) */
110 #define	ZSWR_ENHANCED	7	/* write address of WR7' */
111 
112 /*
113  * Registers 0 through 7 may be written with any one of the 8 command
114  * modifiers, and/or any one of the 4 reset modifiers, defined below.
115  * To write registers 8 through 15, however, the command modifier must
116  * always be `point high'.  Rather than track this bizzareness all over
117  * the driver, we try to avoid using any modifiers, ever (but they are
118  * defined here if you want them).
119  */
120 #define	ZSM_RESET_TXUEOM	0xc0	/* reset xmit underrun / eom latch */
121 #define	ZSM_RESET_TXCRC		0x80	/* reset xmit crc generator */
122 #define	ZSM_RESET_RXCRC		0x40	/* reset recv crc checker */
123 #define	ZSM_NULL		0x00	/* nothing special */
124 
125 #define	ZSM_RESET_IUS		0x38	/* reset interrupt under service */
126 #define	ZSM_RESET_ERR		0x30	/* reset error cond */
127 #define	ZSM_RESET_TXINT		0x28	/* reset xmit interrupt pending */
128 #define	ZSM_EI_NEXTRXC		0x20	/* enable int. on next rcvd char */
129 #define	ZSM_SEND_ABORT		0x18	/* send abort (SDLC) */
130 #define	ZSM_RESET_STINT		0x10	/* reset external/status interrupt */
131 #define	ZSM_POINTHIGH		0x08	/* `point high' (use r8-r15) */
132 #define	ZSM_NULL		0x00	/* nothing special */
133 
134 /*
135  * Commands for Write Register 0 (`Command Register').
136  * These are just the command modifiers or'ed with register number 0
137  * (which of course equals the command modifier).
138  */
139 #define	ZSWR0_RESET_EOM		ZSM_RESET_TXUEOM
140 #define	ZSWR0_RESET_TXCRC	ZSM_RESET_TXCRC
141 #define	ZSWR0_RESET_RXCRC	ZSM_RESET_RXCRC
142 #define	ZSWR0_CLR_INTR		ZSM_RESET_IUS
143 #define	ZSWR0_RESET_ERRORS	ZSM_RESET_ERR
144 #define	ZSWR0_EI_NEXTRXC	ZSM_EI_NEXTRXC
145 #define	ZSWR0_SEND_ABORT	ZSM_SEND_ABORT
146 #define	ZSWR0_RESET_STATUS	ZSM_RESET_STINT
147 #define	ZSWR0_RESET_TXINT	ZSM_RESET_TXINT
148 
149 /*
150  * Bits in Write Register 1 (`Transmit/Receive Interrupt and Data
151  * Transfer Mode Definition').  Note that bits 3 and 4 are taken together
152  * as a single unit, and bits 5 and 6 are useful only if bit 7 is set.
153  */
154 #define	ZSWR1_REQ_WAIT		0x80	/* WAIT*-REQ* pin gives WAIT* */
155 #define	ZSWR1_REQ_REQ		0xc0	/* WAIT*-REQ* pin gives REQ* */
156 #define	ZSWR1_REQ_TX		0x00	/* WAIT*-REQ* pin follows xmit buf */
157 #define	ZSWR1_REQ_RX		0x20	/* WAIT*-REQ* pin follows recv buf */
158 
159 #define	ZSWR1_RIE_NONE		0x00	/* disable rxint entirely */
160 #define	ZSWR1_RIE_FIRST		0x08	/* rxint on first char & on S.C. */
161 #define	ZSWR1_RIE		0x10	/* rxint per char & on S.C. */
162 #define	ZSWR1_RIE_SPECIAL_ONLY	0x18	/* rxint on S.C. only */
163 
164 #define	ZSWR1_PE_SC		0x04	/* parity error is special condition */
165 #define	ZSWR1_TIE		0x02	/* transmit interrupt enable */
166 #define	ZSWR1_SIE		0x01	/* external/status interrupt enable */
167 
168 #define	ZSWR1_IMASK 	0x1F	/* mask of all itr. enable bits. */
169 
170 /* HSIS compat */
171 #define	ZSWR1_REQ_ENABLE	(ZSWR1_REQ_WAIT | ZSWR1_REQ_TX)
172 
173 /*
174  * Bits in Write Register 3 (`Receive Parameters and Control').
175  * Bits 7 and 6 are taken as a unit.  Note that the receive bits
176  * per character ordering is insane.
177  *
178  * Here `hardware flow control' means CTS enables the transmitter
179  * and DCD enables the receiver.  The latter is neither interesting
180  * nor useful, and gets in our way, making it almost unusable.
181  */
182 #define	ZSWR3_RX_5		0x00	/* receive 5 bits per char */
183 #define	ZSWR3_RX_7		0x40	/* receive 7 bits per char */
184 #define	ZSWR3_RX_6		0x80	/* receive 6 bits per char */
185 #define	ZSWR3_RX_8		0xc0	/* receive 8 bits per char */
186 #define	ZSWR3_RXSIZE		0xc0	/* receive char size mask */
187 
188 #define	ZSWR3_HFC		0x20	/* hardware flow control */
189 #define	ZSWR3_HUNT		0x10	/* enter hunt mode */
190 #define	ZSWR3_RXCRC_ENABLE	0x08	/* enable recv crc calculation */
191 #define	ZSWR3_ADDR_SEARCH_MODE	0x04	/* address search mode (SDLC only) */
192 #define	ZSWR3_SDLC_SHORT_ADDR	0x02	/* short address mode (SDLC only) */
193 #define	ZSWR3_SYNC_LOAD_INH	0x02	/* sync character load inhibit */
194 #define	ZSWR3_RX_ENABLE		0x01	/* receiver enable */
195 
196 /*
197  * Bits in Write Register 4 (`Transmit/Receive Miscellaneous Parameters
198  * and Modes').  Bits 7&6, 5&4, and 3&2 are taken as units.
199  */
200 #define	ZSWR4_CLK_X1		0x00	/* clock divisor = 1 */
201 #define	ZSWR4_CLK_X16		0x40	/* clock divisor = 16 */
202 #define	ZSWR4_CLK_X32		0x80	/* clock divisor = 32 */
203 #define	ZSWR4_CLK_X64		0xc0	/* clock divisor = 64 */
204 #define	ZSWR4_CLK_MASK		0xc0	/* clock divisor mask */
205 
206 #define	ZSWR4_MONOSYNC		0x00	/* 8 bit sync char (sync only) */
207 #define	ZSWR4_BISYNC		0x10	/* 16 bit sync char (sync only) */
208 #define	ZSWR4_SDLC  		0x20	/* SDLC mode */
209 #define	ZSWR4_EXTSYNC		0x30	/* external sync mode */
210 #define	ZSWR4_SYNC_MASK		0x30	/* sync mode bit mask */
211 
212 #define	ZSWR4_SYNCMODE		0x00	/* no stop bit (sync mode only) */
213 #define	ZSWR4_ONESB 		0x04	/* 1 stop bit */
214 #define	ZSWR4_1P5SB 		0x08	/* 1.5 stop bits (clk cannot be 1x) */
215 #define	ZSWR4_TWOSB 		0x0c	/* 2 stop bits */
216 #define	ZSWR4_SBMASK		0x0c	/* mask of all stop bits */
217 
218 #define	ZSWR4_EVENP 		0x02	/* check for even parity */
219 #define	ZSWR4_PARENB		0x01	/* enable parity checking */
220 #define	ZSWR4_PARMASK		0x03	/* mask of all parity bits */
221 
222 /*
223  * Bits in Write Register 5 (`Transmit Parameter and Controls').
224  * Bits 6 and 5 are taken as a unit; the ordering is, as with RX
225  * bits per char, not sensible.
226  */
227 #define	ZSWR5_DTR		0x80	/* assert (set to -12V) DTR */
228 
229 #define	ZSWR5_TX_5		0x00	/* transmit 5 or fewer bits */
230 #define	ZSWR5_TX_7		0x20	/* transmit 7 bits */
231 #define	ZSWR5_TX_6		0x40	/* transmit 6 bits */
232 #define	ZSWR5_TX_8		0x60	/* transmit 8 bits */
233 #define	ZSWR5_TXSIZE		0x60	/* transmit char size mask */
234 
235 #define	ZSWR5_BREAK		0x10	/* send break (continuous 0s) */
236 #define	ZSWR5_TX_ENABLE		0x08	/* enable transmitter */
237 #define	ZSWR5_CRC16		0x04	/* use CRC16 (off => use SDLC) */
238 #define	ZSWR5_RTS		0x02	/* assert RTS */
239 #define	ZSWR5_TXCRC_ENABLE	0x01	/* enable xmit crc calculation */
240 
241 #ifdef not_done_here
242 /*
243  * Bits in Write Register 7 when the chip is in SDLC mode.
244  */
245 #define	ZSWR7_SDLCFLAG		0x7e	/* this value makes SDLC mode work */
246 #endif
247 
248 /*
249  * Bits in Write Register 7' (ZSWR_ENHANCED above). This register is
250  * only available on the 85230. Dispite the fact it contains flags
251  * and not a single value, the register was named as it is read
252  * via RR14. Weird.
253  */
254 			/*	0x80	unused */
255 #define	ZSWR7P_EXTEND_READ	0x40	/* modify read map; make most regs readable */
256 #define	ZSWR7P_TX_FIFO		0x20	/* change level for Tx FIFO empty int */
257 #define	ZSWR7P_DTR_TIME		0x10	/* modifies deact. speed of /DTR//REQ */
258 #define	ZSWR7P_RX_FIFO		0x08	/* Rx FIFO int on 1/2 full? */
259 #define	ZSWR7P_RTS_DEACT	0x04	/* automatically deassert RTS */
260 #define	ZSWR7P_AUTO_EOM_RESET	0x02	/* automatically reset EMO/Tx Underrun */
261 #define	ZSWR7P_AUTO_TX_FLAG	0x01	/* Auto send SDLC flag at transmit start */
262 
263 /*
264  * Bits in Write Register 9 (`Master Interrupt Control').  Bits 7 & 6
265  * are taken as a unit and indicate the type of reset; 00 means no reset
266  * (and is not defined here).
267  */
268 #define	ZSWR9_HARD_RESET	0xc0	/* force hardware reset */
269 #define	ZSWR9_A_RESET		0x80	/* reset channel A (0) */
270 #define	ZSWR9_B_RESET		0x40	/* reset channel B (1) */
271 #define	ZSWR9_SOFT_INTAC	0x20	/* Not in NMOS version */
272 
273 #define	ZSWR9_STATUS_HIGH	0x10	/* status in high bits of intr vec */
274 #define	ZSWR9_MASTER_IE		0x08	/* master interrupt enable */
275 #define	ZSWR9_DLC		0x04	/* disable lower chain */
276 #define	ZSWR9_NO_VECTOR		0x02	/* no vector */
277 #define	ZSWR9_VECTOR_INCL_STAT	0x01	/* vector includes status */
278 
279 /*
280  * Bits in Write Register 10 (`Miscellaneous Transmitter/Receiver Control
281  * Bits').  Bits 6 & 5 are taken as a unit, and some of the bits are
282  * meaningful only in certain modes.  Bleah.
283  */
284 #define	ZSWR10_PRESET_ONES	0x80	/* preset CRC to all 1 (else all 0) */
285 
286 #define	ZSWR10_NRZ		0x00	/* NRZ encoding */
287 #define	ZSWR10_NRZI		0x20	/* NRZI encoding */
288 #define	ZSWR10_FM1		0x40	/* FM1 encoding */
289 #define	ZSWR10_FM0		0x60	/* FM0 encoding */
290 
291 #define	ZSWR10_GA_ON_POLL	0x10	/* go active on poll (loop mode) */
292 #define	ZSWR10_MARK_IDLE	0x08	/* all 1s (vs flag) when idle (SDLC) */
293 #define	ZSWR10_ABORT_ON_UNDERRUN 0x4	/* abort on xmit underrun (SDLC) */
294 #define	ZSWR10_LOOP_MODE	0x02	/* loop mode (SDLC) */
295 #define	ZSWR10_6_BIT_SYNC	0x01	/* 6 bits per sync char (sync modes) */
296 
297 /*
298  * Bits in Write Register 11 (`Clock Mode Control').  Bits 6&5, 4&3, and
299  * 1&0 are taken as units.  Various bits depend on other bits in complex
300  * ways; see the Zilog manual.
301  */
302 #define	ZSWR11_XTAL		0x80	/* have xtal between RTxC* and SYNC* */
303 					/* (else have TTL oscil. on RTxC*) */
304 #define	ZSWR11_RXCLK_RTXC	0x00	/* recv clock taken from RTxC* pin */
305 #define	ZSWR11_RXCLK_TRXC	0x20	/* recv clock taken from TRxC* pin */
306 #define	ZSWR11_RXCLK_BAUD	0x40	/* recv clock taken from BRG */
307 #define	ZSWR11_RXCLK_DPLL	0x60	/* recv clock taken from DPLL */
308 
309 #define	ZSWR11_TXCLK_RTXC	0x00	/* xmit clock taken from RTxC* pin */
310 #define	ZSWR11_TXCLK_TRXC	0x08	/* xmit clock taken from TRxC* pin */
311 #define	ZSWR11_TXCLK_BAUD	0x10	/* xmit clock taken from BRG */
312 #define	ZSWR11_TXCLK_DPLL	0x18	/* xmit clock taken from DPLL */
313 
314 #define	ZSWR11_TRXC_OUT_ENA	0x04	/* TRxC* pin will be an output */
315 					/* (unless it is being used above) */
316 #define	ZSWR11_TRXC_XTAL	0x00	/* TRxC output from xtal oscillator */
317 #define	ZSWR11_TRXC_XMIT	0x01	/* TRxC output from xmit clock */
318 #define	ZSWR11_TRXC_BAUD	0x02	/* TRxC output from BRG */
319 #define	ZSWR11_TRXC_DPLL	0x03	/* TRxC output from DPLL */
320 
321 /*
322  * Formula for Write Registers 12 and 13 (`Lower Byte of Baud Rate
323  * Generator Time Constant' and `Upper Byte of ...').  Inputs:
324  *
325  *	f	BRG input clock frequency (in Hz) AFTER division
326  *		by 1, 16, 32, or 64 (per clock divisor in WR4)
327  *	bps	desired rate in bits per second (9600, etc)
328  *
329  * We want
330  *
331  *	  f
332  *	----- + 0.5 - 2
333  *	2 bps
334  *
335  * rounded down to an integer.  This can be computed entirely
336  * in integer arithemtic as:
337  *
338  *	f + bps
339  *	------- - 2
340  *	 2 bps
341  */
342 #define	BPS_TO_TCONST(f, bps)	((((f) + (bps)) / (2 * (bps))) - 2)
343 
344 /* inverse of above: given a BRG Time Constant, return Bits Per Second */
345 #define	TCONST_TO_BPS(f, tc)	((f) / 2 / ((tc) + 2))
346 
347 /*
348  * Bits in Write Register 14 (`Miscellaneous Control Bits').
349  * Bits 7 through 5 are taken as a unit and make up a `DPLL command'.
350  */
351 #define	ZSWR14_DPLL_NOOP	0x00	/* leave DPLL alone */
352 #define	ZSWR14_DPLL_SEARCH	0x20	/* enter search mode */
353 #define	ZSWR14_DPLL_RESET_CM	0x40	/* reset `clock missing' in RR10 */
354 #define	ZSWR14_DPLL_DISABLE	0x60	/* disable DPLL (continuous search) */
355 #define	ZSWR14_DPLL_SRC_BAUD	0x80	/* set DPLL src = BRG */
356 #define	ZSWR14_DPLL_SRC_RTXC	0xa0	/* set DPLL src = RTxC* or xtal osc */
357 #define	ZSWR14_DPLL_FM		0xc0	/* operate in FM mode */
358 #define	ZSWR14_DPLL_NRZI	0xe0	/* operate in NRZI mode */
359 
360 #define	ZSWR14_LOCAL_LOOPBACK	0x10	/* set local loopback mode */
361 #define	ZSWR14_AUTO_ECHO	0x08	/* set auto echo mode */
362 #define	ZSWR14_DTR_REQ		0x04	/* DTR* / REQ* pin gives REQ* */
363 #define	ZSWR14_BAUD_FROM_PCLK	0x02	/* BRG clock taken from PCLK */
364 					/* (else from RTxC* pin or xtal osc) */
365 #define	ZSWR14_BAUD_ENA		0x01	/* enable BRG countdown */
366 
367 /*
368  * Bits in Write Register 15 (`External/Status Interrupt Control').
369  * Most of these cause status interrupts whenever the corresponding
370  * bit or pin changes state (i.e., any rising or falling edge).
371  *
372  * NOTE: ZSWR15_SDLC_FIFO & ZSWR15_ENABLE_ENHANCED should not be
373  * set on an NMOS 8530. Also, ZSWR15_ENABLE_ENHANCED is only
374  * available on the 85230.
375  */
376 #define	ZSWR15_BREAK_IE		0x80	/* enable break/abort status int */
377 #define	ZSWR15_TXUEOM_IE	0x40	/* enable TX underrun/EOM status int */
378 #define	ZSWR15_CTS_IE		0x20	/* enable CTS* pin status int */
379 #define	ZSWR15_SYNCHUNT_IE	0x10	/* enable SYNC* pin/hunt status int */
380 #define	ZSWR15_DCD_IE		0x08	/* enable DCD* pin status int */
381 #define	ZSWR15_SDLC_FIFO	0x04	/* enable SDLC FIFO enhancements */
382 #define	ZSWR15_ZERO_COUNT_IE	0x02	/* enable BRG-counter = 0 status int */
383 #define	ZSWR15_ENABLE_ENHANCED	0x01	/* enable writing WR7' at reg 7 */
384 
385 /*
386  * Bits in Read Register 0 (`Transmit/Receive Buffer Status and External
387  * Status').
388  */
389 #define	ZSRR0_BREAK		0x80	/* break/abort detected */
390 #define	ZSRR0_TXUNDER		0x40	/* transmit underrun/EOM (sync) */
391 #define	ZSRR0_CTS		0x20	/* clear to send */
392 #define	ZSRR0_SYNC_HUNT		0x10	/* sync/hunt (sync mode) */
393 #define	ZSRR0_DCD		0x08	/* data carrier detect */
394 #define	ZSRR0_TX_READY		0x04	/* transmit buffer empty */
395 #define	ZSRR0_ZERO_COUNT	0x02	/* zero count in baud clock */
396 #define	ZSRR0_RX_READY		0x01	/* received character ready */
397 
398 /*
399  * Bits in Read Register 1 (the Zilog book does not name this one).
400  */
401 #define	ZSRR1_EOF		0x80	/* end of frame (SDLC mode) */
402 #define	ZSRR1_FE		0x40	/* CRC/framing error */
403 #define	ZSRR1_DO		0x20	/* data (receiver) overrun */
404 #define	ZSRR1_PE		0x10	/* parity error */
405 #define	ZSRR1_RC0		0x08	/* residue code 0 (SDLC mode) */
406 #define	ZSRR1_RC1		0x04	/* residue code 1 (SDLC mode) */
407 #define	ZSRR1_RC2		0x02	/* residue code 2 (SDLC mode) */
408 #define	ZSRR1_ALL_SENT		0x01	/* all chars out of xmitter (async) */
409 
410 /*
411  * Read Register 2 in B channel contains status bits if VECTOR_INCL_STAT
412  * is set.
413  */
414 
415 /*
416  * Bits in Read Register 3 (`Interrupt Pending').  Only channel A
417  * has an RR3.
418  */
419 			/*	0x80	   unused, returned as 0 */
420 			/*	0x40	   unused, returned as 0 */
421 #define	ZSRR3_IP_A_RX		0x20	/* channel A recv int pending */
422 #define	ZSRR3_IP_A_TX		0x10	/* channel A xmit int pending */
423 #define	ZSRR3_IP_A_STAT		0x08	/* channel A status int pending */
424 #define	ZSRR3_IP_B_RX		0x04	/* channel B recv int pending */
425 #define	ZSRR3_IP_B_TX		0x02	/* channel B xmit int pending */
426 #define	ZSRR3_IP_B_STAT		0x01	/* channel B status int pending */
427 
428 /*
429  * Bits in Read Register 10 (`contains some miscellaneous status bits').
430  */
431 #define	ZSRR10_1_CLOCK_MISSING	0x80	/* 1 clock edge missing (FM mode) */
432 #define	ZSRR10_2_CLOCKS_MISSING	0x40	/* 2 clock edges missing (FM mode) */
433 			/*	0x20	   unused */
434 #define	ZSRR10_LOOP_SENDING	0x10	/* xmitter controls loop (SDLC loop) */
435 			/*	0x08	   unused */
436 			/*	0x04	   unused */
437 #define	ZSRR10_ON_LOOP		0x02	/* SCC is on loop (SDLC/X.21 modes) */
438 
439 /*
440  * Bits in Read Register 15.  This register is one of the few that
441  * simply reads back the corresponding Write Register.
442  */
443 #define	ZSRR15_BREAK_IE		0x80	/* break/abort status int enable */
444 #define	ZSRR15_TXUEOM_IE	0x40	/* TX underrun/EOM status int enable */
445 #define	ZSRR15_CTS_IE		0x20	/* CTS* pin status int enable */
446 #define	ZSRR15_SYNCHUNT_IE	0x10	/* SYNC* pin/hunt status int enable */
447 #define	ZSRR15_DCD_IE		0x08	/* DCD* pin status int enable */
448 			/*	0x04	   unused, returned as zero */
449 #define	ZSRR15_ZERO_COUNT_IE	0x02	/* BRG-counter = 0 status int enable */
450 			/*	0x01	   unused, returned as zero */
451