1bpp(7D) Devices bpp(7D)
2
6 bpp - bi-directional parallel port driver
7
9 SUNW,bpp@slot,offset:bppn
10
13 The bpp driver provides a general-purpose bi-directional interface to
14 parallel devices. It supports a variety of output (printer) and input
15 (scanner) devices, using programmable timing relationships between the
16 various handshake signals.
17
19 The bpp driver is an exclusive-use device. If the device has already
20 been opened, subsequent opens fail with EBUSY.
21 Default Operation
23 Each time the bpp device is opened, the default configuration is
24 BPP_ACK_BUSY_HS for read handshake, BPP_ACK_HS for write handshake, 1
25 microsecond for all setup times and strobe widths, and 60 seconds for
26 both timeouts. This configuration (in the write mode) drives many com‐
27 mon personal computer parallel printers with Centronics-type inter‐
28 faces. The application should use the BPPIOC_SETPARMS ioctl request to
29 configure the bpp for the particular device which is attached, if nec‐
30 essary.
31 Write Operation
33 If a failure or error condition occurs during a write(2), the number of
34 bytes successfully written is returned (short write). Note that errno
35 will not be set. The contents of certain status bits will be captured
36 at the time of the error, and can be retrieved by the application pro‐
37 gram, using the BPPIOC_GETERR ioctl request. Subsequent write(2) calls
38 may fail with the system error ENXIO if the error condition is not
39 rectified. The captured status information will be overwritten each
40 time an attempted transfer or a BPPIOC_TESTIO ioctl request occurs.
41 Read Operations
43 If a failure or error condition occurs during a read(2), the number of
44 bytes successfully read is returned (short read). Note that errno will
45 not be set. The contents of certain status bits will be captured at the
46 time of the error, and can be retrieved by the application, using the
47 BPPIOC_GETERR ioctl request. Subsequent read(2) calls may fail with
48 ENXIO if the error condition is not rectified. The captured register
49 information will be overwritten each time an attempted transfer or a
50 BPPIOC_TESTIO ioctl request.
51 If the read_handshake element of the bpp_transfer_parms structure
54 (see below) is set to BPP_CLEAR_MEM or BPP_SET_MEM, zeroes or ones,
55 respectively, are written into the user buffer.
56 Read/Write Operation
58 When the driver is opened for reading and writing, it is assumed that
59 scanning will take place, as scanners are the only devices supported by
60 this mode. Most scanners require that the SLCT_IN or AFX pin be set to
61 tell the scanner the direction of the transfer. The AFX line is set
62 when the read_handshake element of the bpp_transfer_parms structure is
63 set to BPP_HSCAN_HS, otherwise the SLCT_IN pin is set. Normally, scan‐
64 ning starts by writing a command to the scanner, at which time the pin
65 is set. When the scan data is read back, the pin is reset.
66
68 The following ioctl requests are supported:
69 BPPIOC_SETPARMS Set transfer parameters.
71 The argument is a pointer to a bpp_transfer_parms
73 structure. See below for a description of the ele‐
74 ments of this structure. If a parameter is out of
75 range, EINVAL is returned.
76 BPPIOC_GETPARMS Get current transfer parameters.
79 The argument is a pointer to a bpp_transfer_parms
81 structure. See below for a description of the ele‐
82 ments of this structure. If no parameters have
83 been configured since the device was opened, the
84 contents of the structure will be the default con‐
85 ditions of the parameters (see Default Operation
86 above).
87 BPPIOC_SETOUTPINS Set output pin values.
90 The argument is a pointer to a bpp_pins struc‐
92 ture. See below for a description of the elements
93 of this structure. If a parameter is out of range,
94 EINVAL is returned.
95 BPPIOC_GETOUTPINS Read output pin values. The argument is a pointer
98 to a bpp_pins structure. See below for a descrip‐
99 tion of the elements of this structure.
100 BPPIOC_GETERR Get last error status.
103 The argument is a pointer to a bpp_error_status
105 structure. See below for a description of the ele‐
106 ments of this structure. This structure indicates
107 the status of all the appropriate status bits at
108 the time of the most recent error condition during
109 a read(2) or write(2) call, or the status of the
110 bits at the most recent BPPIOC_TESTIO ioctl
111 request. Note: The bits in the pin_status ele‐
112 ment indicate whether the associated pin is
113 active, not the actual polarity. The application
114 can check transfer readiness without attempting
115 another transfer using the BPPIOC_TESTIO ioctl.
116 Note: The timeout_occurred and bus_error fields
117 will never be set by the BPPIOC_TESTIO ioctl,
118 only by an actual failed transfer.
119 BPPIOC_TESTIO Test transfer readiness.
122 This command checks to see if a read or write
124 transfer would succeed based on pin status, opened
125 mode, and handshake selected. If a handshake would
126 succeed, 0 is returned. If a transfer would fail,
127 -1 is returned, and errno is set to EIO, and the
128 error status information is captured. The captured
129 status can be retrieved using the BPPIOC_GETERR
130 ioctl call. Note that the timeout_occurred and
131 bus_error fields will never be set by this ioctl.
132 Transfer Parameters Structure
135 This structure is defined in <sys/bpp_io.h>.
136 struct bpp_transfer_parms {
138 enum handshake_t
139 read_handshake; /* parallel port read handshake mode */
140 int read_setup_time; /* DSS register - in nanoseconds */
141 int read_strobe_width; /* DSW register - in nanoseconds */
142 int read_timeout; /*
143 * wait this many seconds
144 * before aborting a transfer
145 */
146 enum handshake_t
147 write_handshake; /* parallel port write handshake mode */
148 int write_setup_time; /* DSS register - in nanoseconds */
149 int write_strobe_width; /* DSW register - in nanoseconds */
150 int write_timeout; /*
151 * wait this many seconds
152 * before aborting a transfer
153 */
154 };
155 /* Values for read_handshake and write_handshake fields */
156 enum handshake_t {
157 BPP_NO_HS, /* no handshake pins */
158 BPP_ACK_HS, /* handshake controlled by ACK line */
159 BPP_BUSY_HS, /* handshake controlled by BSY line */
160 BPP_ACK_BUSY_HS, /*
161 * handshake controlled by ACK and BSY lines
162 * read_handshake only!
163 */
164 BPP_XSCAN_HS, /* xerox scanner mode,
165 * read_handshake only!
166 */
167 BPP_HSCAN_HS, /*
168 * HP scanjet scanner mode
169 * read_handshake only!
170 */
171 BPP_CLEAR_MEM, /* write 0's to memory,
172 * read_handshake only!
173 */
174 BPP_SET_MEM, /* write 1's to memory,
175 * read_handshake only!
176 */
177 /* The following handshakes are RESERVED. Do not use. */
178 BPP_VPRINT_HS, /* valid only in read/write mode */
179 BPP_VPLOT_HS /* valid only in read/write mode */
180 };
181 The read_setup_time field controls the time between dstrb falling edge
185 to bsy rising edge if the read_handshake field is set to BPP_NO_HS or
186 BPP_ACK_HS. It controls the time between dstrb falling edge to ack ris‐
187 ing edge if the read_handshake field is set to BPP_ACK_HS or
188 BPP_ACK_BUSY_HS. It controls the time between ack falling edge to dstrb
189 rising edge if the read_handshake field is set to BPP_XSCAN_HS.
190 The read_strobe_width field controls the time between ack rising edge
193 and ack falling edge if the read_handshake field is set to BPP_NO_HS or
194 BPP_ACK_BUSY_HS. It controls the time between dstrb rising edge to
195 dstrb falling edge if the read_handshake field is set to BPP_XSCAN_HS.
196 The values allowed for the write_handshake field are duplicates of the
199 definitions for the read_handshake field. Note that some of these hand‐
200 shake definitions are only valid in one mode or the other.
201 The write_setup_time field controls the time between data valid to
204 dstrb rising edge for all values of the write_handshake field.
205 The write_strobe_width field controls the time between dstrb rising
208 edge and dstrb falling edge if the write_handshake field is not set to
209 BPP_VPRINT_HS or BPP_VPLOT_HS. It controls the minimum time between
210 dstrb rising edge to dstrb falling edge if the write_handshake field is
211 set to BPP_VPRINT_HS or BPP_VPLOT_HS.
212 Transfer Pins Structure
214 This structure is defined in <sys/bpp_io.h>.
215 struct bpp_pins {
217 uchar_t output_reg_pins; /* pins in P_OR register */
218 uchar_t input_reg_pins; /* pins in P_IR register */
219 };
220 /* Values for output_reg_pins field */
222 #define BPP_SLCTIN_PIN 0x01 /* Select in pin */
223 #define BPP_AFX_PIN 0x02 /* Auto feed pin */
224 #define BPP_INIT_PIN 0x04 /* Initialize pin */
225 #define BPP_V1_PIN 0x08 /* reserved pin 1 */
226 #define BPP_V2_PI 0x10 /* reserved pin 2 */
227 #define BPP_V3_PIN 0x20 /* reserved pin 3 */
228 #define BPP_ERR_PIN 0x01 /* Error pin */
229 #define BPP_SLCT_PIN 0x02 /* Select pin */
230 #define BPP_PE_PIN 0x04 /* Paper empty pin */
231 Error Pins Structure
234 This structure is defined in the include file <sys/bpp_io.h>.
235 struct bpp_error_status {
237 char timeout_occurred; /* 1 if a timeout occurred */
238 char bus_error; /* 1 if an SBus bus error */
239 uchar_t pin_status; /*
240 * status of pins which could
241 * cause an error
242 */
243 };
244 /* Values for pin_status field */
245 #define BPP_ERR_ERR 0x01 /* Error pin active */
246 #define BPP_SLCT_ERR 0x02 /* Select pin active */
247 #define BPP_PE_ERR 0x04 /* Paper empty pin active */
248 #define BPP_SLCTIN_ERR 0x10 /* Select in pin active */
249 #define BPP_BUSY_ERR 0x40 /* Busy pin active */
250
253 EBADF The device is opened for write-only access and a read is
254 attempted, or the device is opened for read-only access and a
255 write is attempted.
256 EBUSY The device has been opened and another open is attempted. An
259 attempt has been made to unload the driver while one of the
260 units is open.
261 EINVAL A BPPIOC_SETPARMS ioctl is attempted with an out of range
264 value in the bpp_transfer_parms structure. A BPPIOC_SETOUT‐
265 PINS ioctl is attempted with an invalid value in the pins
266 structure. An ioctl is attempted with an invalid value in
267 the command argument. An invalid command argument is received
268 during modload(1M) or modunload(1M).
269 EIO The driver encountered an SBus bus error when attempting an
272 access.
273 A read or write does not complete properly, due to a periph‐
275 eral error or a transfer timeout.
276 A BPPIOC_TESTIO ioctl call is attempted while a condition
278 exists which would prevent a transfer (such as a peripheral
279 error).
280 ENXIO The driver has received an open request for a unit for which
283 the attach failed. The driver has received a read or write
284 request for a unit number greater than the number of units
285 available. The driver has received a write request for a unit
286 which has an active peripheral error.
287
290 /dev/bppn bi-directional parallel port devices
291
294 ioctl(2), read(2), write(2), sbus(4)
295SunOS 5.11 22 Aug 1994 bpp(7D)