selphy_print/backend_kodak6800.c

/*
 *   Kodak 6800/6850 Photo Printer CUPS backend -- libusb-1.0 version
 *
 *   (c) 2013-2014 Solomon Peachy <pizza@shaftnet.org>
 *
 *   The latest version of this program can be found at:
 *
 *     http://git.shaftnet.org/cgit/selphy_print.git
 *
 *   This program is free software; you can redistribute it and/or modify it
 *   under the terms of the GNU General Public License as published by the Free
 *   Software Foundation; either version 3 of the License, or (at your option)
 *   any later version.
 *
 *   This program is distributed in the hope that it will be useful, but
 *   WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 *   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 *   for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 *          [http://www.gnu.org/licenses/gpl-3.0.html]
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <signal.h>

#include "backend_common.h"

#define USB_VID_KODAK       0x040A
#define USB_PID_KODAK_6800  0x4021
#define USB_PID_KODAK_6850  0x402B

/* File header */
struct kodak6800_hdr {
	uint8_t  hdr[9];
	uint8_t  copies;
	uint16_t columns;  /* BE */
	uint16_t rows;     /* BE */
	uint8_t  media;    /* 0x06 for 6x8, 0x00 for 6x4, 0x07 for 5x7 */
	uint8_t  laminate; /* 0x01 to laminate, 0x00 for not */
	uint8_t  unk1; /* 0x00, 0x01 [may be print mode] */
} __attribute__((packed));

#define CMDBUF_LEN 17

/* Private data stucture */
struct kodak6800_ctx {
	struct libusb_device_handle *dev;
	uint8_t endp_up;
	uint8_t endp_down;

	int type;
	struct kodak6800_hdr hdr;
	uint8_t *databuf;
	int datalen;
};

/* Program states */
enum {
	S_IDLE = 0,
	S_6850_READY,
	S_6850_READY_WAIT,
	S_READY,
	S_STARTED,
	S_SENT_HDR,
	S_SENT_DATA,
	S_FINISHED,
};

#define READBACK_LEN 68

#define UPDATE_SIZE 1536
static int kodak6800_get_tonecurve(struct kodak6800_ctx *ctx, char *fname)
{
	libusb_device_handle *dev = ctx->dev;
	uint8_t endp_down = ctx->endp_down;
	uint8_t endp_up = ctx->endp_up;

	uint8_t cmdbuf[16];
	uint8_t respbuf[64];
	int ret, num = 0;
	int i;

	uint16_t *data = malloc(UPDATE_SIZE);

	INFO("Dump Tone Curve to '%s'\n", fname);

	/* Initial Request */
	cmdbuf[0] = 0x03;
	cmdbuf[1] = 0x1b;
	cmdbuf[2] = 0x43;
	cmdbuf[3] = 0x48;
	cmdbuf[4] = 0x43;
	cmdbuf[5] = 0x0c;
	cmdbuf[6] = 0x54;
	cmdbuf[7] = 0x4f;
	cmdbuf[8] = 0x4e;
	cmdbuf[9] = 0x45;
	cmdbuf[10] = 0x72;
	cmdbuf[11] = 0x01;
	cmdbuf[12] = 0x00;
	cmdbuf[13] = 0x00;
	cmdbuf[14] = 0x00;
	cmdbuf[15] = 0x00;

	if ((ret = send_data(dev, endp_down,
			     cmdbuf, 16)))
		goto done;
	
	ret = read_data(dev, endp_up,
			respbuf, sizeof(respbuf), &num);
	if (ret < 0)
		goto done;
	
	if (num != 51) {
		ERROR("Short read! (%d/%d)\n", num, 51);
		ret = 4;
		goto done;
	}

	/* Then we can poll the data */
	cmdbuf[0] = 0x03;
	cmdbuf[1] = 0x1b;
	cmdbuf[2] = 0x43;
	cmdbuf[3] = 0x48;
	cmdbuf[4] = 0x43;
	cmdbuf[5] = 0x0c;
	cmdbuf[6] = 0x54;
	cmdbuf[7] = 0x4f;
	cmdbuf[8] = 0x4e;
	cmdbuf[9] = 0x45;
	cmdbuf[10] = 0x20;
	for (i = 0 ; i < 24 ; i++) {
		if ((ret = send_data(dev, endp_down,
				     cmdbuf, 11)))
			goto done;

		ret = read_data(dev, endp_up,
				respbuf, sizeof(respbuf), &num);
		if (ret < 0)
			goto done;

		if (num != 64) {
			ERROR("Short read! (%d/%d)\n", num, 51);
			ret = 4;
			goto done;
		}

		/* Copy into buffer */
		memcpy(((uint8_t*)data)+i*64, respbuf, 64);
	}

	/* Open file and write it out */
	{
		int tc_fd = open(fname, O_WRONLY|O_CREAT, S_IRUSR|S_IWUSR);
		if (tc_fd < 0) {
			ret = 4;
			goto done;
		}

		for (i = 0 ; i < 768; i++) {
			/* Byteswap appropriately */
			data[i] = cpu_to_be16(le16_to_cpu(data[i]));
			write(tc_fd, &data[i], sizeof(uint16_t));
		}
		close(tc_fd);
	}

 done:
	/* We're done */
	free(data);

	return 0;
}

static int kodak6800_set_tonecurve(struct kodak6800_ctx *ctx, char *fname)
{
	libusb_device_handle *dev = ctx->dev;
	uint8_t endp_down = ctx->endp_down;
	uint8_t endp_up = ctx->endp_up;

	uint8_t cmdbuf[64];
	uint8_t respbuf[64];
	int ret, num = 0;
	int remain;

	uint16_t *data = malloc(UPDATE_SIZE);
	uint8_t *ptr;

	INFO("Set Tone Curve from '%s'\n", fname);

	/* Read in file */
	int tc_fd = open(fname, O_RDONLY);
	if (tc_fd < 0) {
		ret = -1;
		goto done;
	}
	if (read(tc_fd, data, UPDATE_SIZE) != UPDATE_SIZE) {
	        ret = -2;
		goto done;
	}
	close(tc_fd);

	/* Byteswap data to printer's format */
	for (ret = 0; ret < (UPDATE_SIZE)/2 ; ret++) {
		data[ret] = cpu_to_le16(be16_to_cpu(data[ret]));
	}

	/* Initial Request */
	cmdbuf[0] = 0x03;
	cmdbuf[1] = 0x1b;
	cmdbuf[2] = 0x43;
	cmdbuf[3] = 0x48;
	cmdbuf[4] = 0x43;
	cmdbuf[5] = 0x0c;
	cmdbuf[6] = 0x54;
	cmdbuf[7] = 0x4f;
	cmdbuf[8] = 0x4e;
	cmdbuf[9] = 0x45;
	cmdbuf[10] = 0x77;
	cmdbuf[11] = 0x01;
	cmdbuf[12] = 0x00;
	cmdbuf[13] = 0x00;
	cmdbuf[14] = 0x00;
	cmdbuf[15] = 0x00;

	if ((ret = send_data(dev, endp_down,
			     cmdbuf, 16)))
		goto done;
	
	ret = read_data(dev, endp_up,
			respbuf, sizeof(respbuf), &num);
	if (ret < 0)
		goto done;
	
	if (num != 51) {
		ERROR("Short read! (%d/%d)\n", num, 51);
		ret = 4;
		goto done;
	}

	ptr = (uint8_t*) data;
	remain = UPDATE_SIZE;
	while (remain > 0) {
		int count = remain > 63 ? 63 : remain;

		cmdbuf[0] = 0x03;
		memcpy(cmdbuf+1, ptr, count);

		remain -= count;
		ptr += count;

		/* Send next block over */
		if ((ret = send_data(dev, endp_down,
				     cmdbuf, count+1)))
			goto done;


		ret = read_data(dev, endp_up,
				respbuf, sizeof(respbuf), &num);
		if (ret < 0)
			goto done;
		
		if (num != 51) {
			ERROR("Short read! (%d/%d)\n", num, 51);
			ret = 4;
			goto done;
		}
	};
        
done:
	/* We're done */
	free(data);
	return ret;
}

static void kodak6800_cmdline(void)
{
	DEBUG("\t\t[ -c filename ]  # Get tone curve\n");
	DEBUG("\t\t[ -C filename ]  # Set tone curve\n");
}

static int kodak6800_cmdline_arg(void *vctx, int argc, char **argv)
{
	struct kodak6800_ctx *ctx = vctx;
	int i;

	/* Reset arg parsing */
	optind = 1;
	opterr = 0;
	while ((i = getopt(argc, argv, "C:c:")) >= 0) {
		switch(i) {
		case 'c':
			if (ctx)
				return kodak6800_get_tonecurve(ctx, optarg);
			else 
				return 1;
		case 'C':
			if (ctx)
				return kodak6800_set_tonecurve(ctx, optarg);
			else 
				return 1;
		default:
			break;  /* Ignore completely */
		}
	}

	return 0;
}


static void *kodak6800_init(void)
{
	struct kodak6800_ctx *ctx = malloc(sizeof(struct kodak6800_ctx));
	if (!ctx)
		return NULL;
	memset(ctx, 0, sizeof(struct kodak6800_ctx));

	ctx->type = P_ANY;

	return ctx;
}

static void kodak6800_attach(void *vctx, struct libusb_device_handle *dev, 
			      uint8_t endp_up, uint8_t endp_down, uint8_t jobid)
{
	struct kodak6800_ctx *ctx = vctx;
	struct libusb_device *device;
	struct libusb_device_descriptor desc;

	UNUSED(jobid);

	ctx->dev = dev;	
	ctx->endp_up = endp_up;
	ctx->endp_down = endp_down;

	device = libusb_get_device(dev);
	libusb_get_device_descriptor(device, &desc);

	/* Map out device type */
	if (desc.idProduct == USB_PID_KODAK_6850)
		ctx->type = P_KODAK_6850;
	else
		ctx->type = P_KODAK_6800;
}


static void kodak6800_teardown(void *vctx) {
	struct kodak6800_ctx *ctx = vctx;

	if (!ctx)
		return;

	if (ctx->databuf)
		free(ctx->databuf);
	free(ctx);
}

static int kodak6800_read_parse(void *vctx, int data_fd) {
	struct kodak6800_ctx *ctx = vctx;
	int ret;

	if (!ctx)
		return 1;

	if (ctx->databuf) {
		free(ctx->databuf);
		ctx->databuf = NULL;
	}

	/* Read in then validate header */
	ret = read(data_fd, &ctx->hdr, sizeof(ctx->hdr));
	if (ret < 0 || ret != sizeof(ctx->hdr)) {
		if (ret == 0)
			return 1;
		ERROR("Read failed (%d/%d/%d)\n", 
		      ret, 0, (int)sizeof(ctx->hdr));
		perror("ERROR: Read failed");
		return ret;
	}
	if (ctx->hdr.hdr[0] != 0x03 ||
	    ctx->hdr.hdr[1] != 0x1b ||
	    ctx->hdr.hdr[2] != 0x43 ||
	    ctx->hdr.hdr[3] != 0x48 ||
	    ctx->hdr.hdr[4] != 0x43) {
		ERROR("Unrecognized data format!\n");
		return(1);
	}

	ctx->datalen = be16_to_cpu(ctx->hdr.rows) * be16_to_cpu(ctx->hdr.columns) * 3;
	ctx->databuf = malloc(ctx->datalen);
	if (!ctx->databuf) {
		ERROR("Memory allocation failure!\n");
		return 2;
	}

	{
		int remain = ctx->datalen;
		uint8_t *ptr = ctx->databuf;
		do {
			ret = read(data_fd, ptr, remain);
			if (ret < 0) {
				ERROR("Read failed (%d/%d/%d)\n", 
				      ret, remain, ctx->datalen);
				perror("ERROR: Read failed");
				return ret;
			}
			ptr += ret;
			remain -= ret;
		} while (remain);
	}

	return 0;
}

static int kodak6800_main_loop(void *vctx, int copies) {
	struct kodak6800_ctx *ctx = vctx;

	uint8_t rdbuf[READBACK_LEN];
	uint8_t rdbuf2[READBACK_LEN];
	uint8_t cmdbuf[CMDBUF_LEN];

	int last_state = -1, state = S_IDLE;
	int num, ret;
	int pending = 0;

	if (!ctx)
		return 1;

top:
	if (state != last_state) {
		if (dyesub_debug)
			DEBUG("last_state %d new %d\n", last_state, state);
	}

	if (pending)
		goto skip_query;

	/* Send Status Query */
	memset(cmdbuf, 0, CMDBUF_LEN);
	cmdbuf[0] = 0x03;
	cmdbuf[1] = 0x1b;
	cmdbuf[2] = 0x43;
	cmdbuf[3] = 0x48;
	cmdbuf[4] = 0x43;
	cmdbuf[5] = 0x03;

	if ((ret = send_data(ctx->dev, ctx->endp_down,
			     cmdbuf, CMDBUF_LEN - 1)))
		return ret;

skip_query:
	/* Read in the printer status */
	ret = read_data(ctx->dev, ctx->endp_up,
			rdbuf, READBACK_LEN, &num);
	if (ret < 0)
		return ret;
	
	if (num < 51) {
		ERROR("Short read! (%d/%d)\n", num, 51);
		return 4;
	}

	if (num != 51 && num != 58 && num != 68) {
		ERROR("Unexpected readback from printer (%d/%d from 0x%02x))\n",
		      num, READBACK_LEN, ctx->endp_up);
		return ret;
	}

	// XXX detect media type based on readback?

	if (memcmp(rdbuf, rdbuf2, READBACK_LEN)) {
		memcpy(rdbuf2, rdbuf, READBACK_LEN);
	} else if (state == last_state) {
		sleep(1);
	}
	last_state = state;

	fflush(stderr);       

	pending = 0;

	switch (state) {
	case S_IDLE:
		INFO("Waiting for printer idle\n");
		if (rdbuf[0] != 0x01 ||
		    rdbuf[1] != 0x02 ||
		    rdbuf[2] != 0x01) {
			break;
		}

		INFO("Printing started; Sending init sequence\n");
		if (ctx->type == P_KODAK_6850)
			state = S_6850_READY;
		else
			state = S_READY;
		break;
	case S_6850_READY:
		INFO("Sending 6850 init sequence\n");
		memset(cmdbuf, 0, CMDBUF_LEN);
		cmdbuf[0] = 0x03;
		cmdbuf[1] = 0x1b;
		cmdbuf[2] = 0x43;
		cmdbuf[3] = 0x48;
		cmdbuf[4] = 0x43;
		cmdbuf[5] = 0x4c;

		if ((ret = send_data(ctx->dev, ctx->endp_down,
				     cmdbuf, CMDBUF_LEN -1)))
			return ret;
		pending = 1;
		state = S_6850_READY_WAIT;	
		break;
	case S_6850_READY_WAIT:
		if (rdbuf[0] != 0x01 ||
		    rdbuf[2] != 0x43) {
			state = S_6850_READY;
			break;
		}
		state = S_READY;
		break;
	case S_READY:
		INFO("Sending attention sequence\n");
		/* Send reset/attention */
		memset(cmdbuf, 0, CMDBUF_LEN);
		cmdbuf[0] = 0x03;
		cmdbuf[1] = 0x1b;
		cmdbuf[2] = 0x43;
		cmdbuf[3] = 0x48;
		cmdbuf[4] = 0x43;
		cmdbuf[5] = 0x1a;

		if ((ret = send_data(ctx->dev, ctx->endp_down,
				     cmdbuf, CMDBUF_LEN -1)))
			return ret;
		pending = 1;
		state = S_STARTED;
		break;
	case S_STARTED:
		if (rdbuf[0] != 0x01 ||
		    rdbuf[2] != 0x00)
			break;

		/* Aappears to depend on media */
		if (rdbuf[1] != 0x0b &&
		    rdbuf[1] != 0x03)
			break;

		memcpy(cmdbuf, &ctx->hdr, CMDBUF_LEN);

		/* 6850 uses same spool format but different header gets sent */
		if (ctx->type == P_KODAK_6850) {
			if (ctx->hdr.media == 0x00)
				cmdbuf[7] = 0x04;
			else if (ctx->hdr.media == 0x06)
				cmdbuf[7] = 0x05;
		}

		/* If we're printing a 4x6 on 8x6 media... */
		if (ctx->hdr.media == 0x00 &&
		    rdbuf[11] == 0x09 &&
		    rdbuf[12] == 0x82) {
			cmdbuf[14] = 0x06;
			cmdbuf[16] = 0x01;
		}

		INFO("Sending image header\n");
		if ((ret = send_data(ctx->dev, ctx->endp_down,
				     cmdbuf, CMDBUF_LEN)))
			return ret;
		pending = 1;
		state = S_SENT_HDR;
		break;
	case S_SENT_HDR:
		INFO("Waiting for printer to accept data\n");
		if (rdbuf[0] != 0x01 ||
		    rdbuf[1] != 0x02 ||
		    rdbuf[2] != 0x01) {
			break;
		}

		INFO("Sending image data\n");
		if ((ret = send_data(ctx->dev, ctx->endp_down, 
				     ctx->databuf, ctx->datalen)))
			return ret;

		INFO("Image data sent\n");
		state = S_SENT_DATA;
		break;
	case S_SENT_DATA:
		INFO("Waiting for printer to acknowledge completion\n");
		if (rdbuf[0] != 0x01 ||
		    rdbuf[1] != 0x02 ||
		    rdbuf[2] != 0x01) {
			break;
		}

		state = S_FINISHED;
		break;
	default:
		break;
	};

	if (state != S_FINISHED)
		goto top;

	/* Clean up */
	if (terminate)
		copies = 1;

	INFO("Print complete (%d copies remaining)\n", copies - 1);

	if (copies && --copies) {
		state = S_IDLE;
		goto top;
	}

	return 0;
}

/* Exported */
struct dyesub_backend kodak6800_backend = {
	.name = "Kodak 6800/6850",
	.version = "0.31",
	.uri_prefix = "kodak6800",
	.cmdline_usage = kodak6800_cmdline,
	.cmdline_arg = kodak6800_cmdline_arg,
	.init = kodak6800_init,
	.attach = kodak6800_attach,
	.teardown = kodak6800_teardown,
	.read_parse = kodak6800_read_parse,
	.main_loop = kodak6800_main_loop,
	.devices = { 
	{ USB_VID_KODAK, USB_PID_KODAK_6800, P_KODAK_6800, "Kodak"},
	{ USB_VID_KODAK, USB_PID_KODAK_6850, P_KODAK_6850, "Kodak"},
	{ 0, 0, 0, ""}
	}
};

/* Kodak 6800/6850 data format

  Spool file consists of 17-byte header followed by plane-interleaved BGR data.
  Native printer resolution is 1844 pixels per row, and 1240 or 2434 rows.

  6850 Adds support for 5x7, with 1548 pixels per row and 2140 columns.

  Header:

  03 1b 43 48 43 0a 00 01 00     Fixed header
  CC                             Number of copies
  WW WW                          Number of columns, big endian. (Fixed at 1844 on 6800)
  HH HH                          Number of rows, big endian.
  DD                             0x00 (4x6) 0x06 (8x6) 0x07 (5x7 on 6850)
  LL                             Laminate, 0x00 (off) or 0x01 (on)
  00

  ************************************************************************

   Kodak 6800 Printer Comms:

   [[file header]] 03 1b 43 48 43 0a 00 01  00 CC WW WW HH HH MT LL 00

->  03 1b 43 48 43 03 00 00  00 00 00 00 00 00 00 00  [status query]
<-  [51 octets]

    01 02 01 00 00 00 00 00  00 00 a2 7b 00 00 a2 7b
    00 00 02 f4 00 00 e6 b1  00 00 00 1a 00 03 00 e8
    00 01 00 83 00 00 00 00  00 00 00 00 00 00 00 00
    00 00 00

->  03 1b 43 48 43 1a 00 00  00 00 00 00 00 00 00 00  [get ready]
<-  [58 octets]

    01 XX 00 00 00 00 00 04  06 WW WW MM MM 01 00 00  [MM MM == max printable size of media, 09 82 == 2434 for 6x8!]
    00 00 06 WW WW 09 ba 01  02 00 00 00 06 WW WW HH  [09 ba == 2940 == cut area?]
    HH 01 01 00 00 00 06 WW  WW MM MM 01 03 00 00 00  [XX == media type?; 0b/03]
    00 00 00 00 00 00 00 00  00 00

->  03 1b 43 48 43 0a 00 01  00 01 WW WW HH HH 06 01  [ image header, modified (trailing 0x01, '0x06' as media type) ]
    01 

<-  [51 octets]

    01 02 01 00 00 00 00 00  00 00 a2 7b 00 00 a2 7b
    00 00 02 f4 00 00 e6 b1  00 00 00 1a 00 03 00 e8
    00 01 00 83 01 00 00 01  00 00 00 01 00 00 00 00 [ note the "01" after "83", and the extra two "01"s ]
    00 00 00

->  [4K of plane data]
->  ...
->  [4K of plane data]
->  [remainder of plane data + 17 bytes of 0xff]

->  03 1b 43 48 43 03 00 00  00 00 00 00 00 00 00 00 [status query]
<-  [51 octets]

    01 02 01 00 00 00 00 00  00 00 a2 7c 00 00 a2 7c [ note a2 7c vs a2 7b ]
    00 00 01 7a 00 00 e6 b3  00 00 00 1a 00 03 00 e8 [ note 01 7a vs 02 f4, e6 b3 vs e6 b1 ]
    00 01 00 83 01 00 00 00  00 01 00 01 00 00 00 00 [ note the moved '01' in the middle ]
    00 00 00

->  03 1b 43 48 43 03 00 00  00 00 00 00 00 00 00 00 [ status query ]
<-  [51 octets, repeats]

  Other stuff seen:

->  03 1b 43 48 43 12 00 00  00 00 00 00 00 00 00 00
<-  [32 octets]

    00 20 20 20 20 20 20 20  20 20 20 20 20 20 20 20  [[ Pascal string? ]]
    20 20 20 20 20 20 20 20  36 30 34 33 4d 32 38 31  [[ ..."  6043M281" ]]

->  03 1b 43 48 43 0c 54 4f  4e 45 65 00 00 00 00 00
<-  [51 octets]

    [[ typical status response ]]
    [[ Followed by reset. ]]

  Read tone curve data:  

->  03 1b 43 48 43 0c 54 4f  4e 45 72 01 00 00 00 00
<-  [51 octets]

    [[ typical status response ]]

->  03 1b 43 48 43 0c 54 4f  4e 45 20
<-  [64 octets]

    81 01 07 07 27 07 72 07  c8 07 f8 07 22 07 48 08
    68 08 88 08 b3 08 db 08  f7 08 09 09 2e 09 49 09
    65 09 80 09 aa 09 ca 09  e2 09 fa 09 12 0a 32 0a
    42 0a 66 0a 81 0a 9a 0a  c3 0a d9 0a ee 0a 04 0b

->  03 1b 43 48 43 0c 54 4f  4e 45 20
<-  [64 octets]

  [[ repeats for total of 24 packets.  total of 1.5KiB. ]]

  Write tone curve data:

->  03 1b 43 48 43 0c 54 4f  4e 45 77 01 00 00 00 00
<-  [51 octets]

    [[ typical status response ]]

->  03 00 00 46 06 53 06 c0  06 07 07 37 07 5d 07 87 
    07 a1 07 c8 07 08 08 08  08 08 08 48 08 68 08 88
    08 a9 08 b9 08 d9 08 f9  08 12 09 2e 09 49 09 70
    09 89 08 99 09 ba 09 ca  08 da 09 0a 0a 24 0a 38
<-  [51 octets]

    [[ typical status response ]]

->  03 0a 53 0a 66 0a 81 0a ...
   ....
->  03 cf 38 0a 39 3d 39 79  39 96 39 b6 39 fb 39 01
    34 0a 34 08 3a 0c 1a 10  3a
<-  [51 octets]

    [[ typical status response ]]

  [[ total of 24 packets * 64, and then one final packet of 25: 1562 total. ]]
  [[ It apepars the extra 25 bytes are to compensate for the leading '03' on 
     each of the 25 URBs. ]]

   ***********************************************************************

   Kodak 6850 Printer Comms:

   [[file header]] 03 1b 43 48 43 0a 00 01  00 CC WW WW HH HH MT LL 00

->  03 1b 43 48 43 03 00 00  00 00 00 00 00 00 00 00  [status query]
<-  [51 octets]

    01 02 01 00 00 00 00 00  00 00 21 75 00 00 08 52
    00 00 01 29 00 00 3b 0a  00 00 00 0e 00 03 02 90
    00 01 02 1d 03 00 00 00  00 01 00 01 00 00 00 00
    00 00 00

->  03 1b 43 48 43 4c 00 00  00 00 00 00 00 00 00 00  [???]
<-  [51 octets]

    01 01 43 48 43 4c 00 00  00 00 00 00 00 00 00 00
    00 00 01 29 00 00 3b 0a  00 00 00 0e 00 03 02 90
    00 01 02 1d 03 00 00 00  00 01 00 01 00 00 00 00
    00 00 00

->  03 1b 43 48 43 03 00 00  00 00 00 00 00 00 00 00  [status query]
<-  [51 octets -- same as status query before ]

->  03 1b 43 48 43 1a 00 00  00 00 00 00 00 00 00 00  [get ready]
<-  [68 octets]

    01 XX 00 00 00 00 00 06  06 WW WW MM MM 01 00 00  [MM MM == max printable size of media, 09 82 == 2434 for 6x8!]
    00 00 06 WW WW 09 ba 01  02 01 00 00 06 WW WW HH  [09 ba == 2940 == cut area?]
    HH 01 01 00 00 00 06 WW  WW MM MM 01 03 00 00 00  [XX == media type? 03/0b ]
    06 WW WW 09 ba 01 05 01  00 00 06 WW WW HH HH 01
    04 00 00 00

->  03 1b 43 48 43 0a 00 04  00 01 07 34 04 d8 06 01 [ image header, modified ] 
    01       [ note we use '04' for 4x6, '05' for 6x8. last octet is always 0x01 when 4x6. ]

<-  [51 octets]

    01 02 01 00 00 00 00 00  00 00 21 75 00 00 08 52
    00 00 01 29 00 00 3b 0a  00 00 00 0e 00 03 02 90
    00 01 02 1d 04 00 00 01  00 00 00 01 00 00 00 00 [ note the "04" after "1d", and the moved '01' ]
    00 00 00

->  [4K of plane data]
->  ...
->  [4K of plane data]
->  [remainder of plane data]

->  03 1b 43 48 43 03 00 00  00 00 00 00 00 00 00 00 [status query]
<-  [51 octets]

    01 02 01 00 00 00 00 00  00 00 21 76 00 00 08 53 [ note 21 76, 08 53, 01 2a incremented by 1 ]
    00 00 01 2a 00 00 3b 0c  00 00 00 0e 00 03 02 90 [ note 3b 0c incremeted by 2 ]
    00 01 02 1d 04 00 00 01  00 00 00 01 00 00 00 00
    00 00 00

  Other stuff seen:

->  03 1b 43 48 43 12 00 00  00 00 00 00 00 00 00 00  
    00 
<-  [32 octets]

    00 20 20 20 20 20 20 20  20 20 20 20 20 20 20 20  [[ Pascal string? ]]
    20 20 20 20 20 20 20 20  36 30 39 37 4b 53 34 39  [[ ..."  6097KS49" ]]

  Read tone curve data:  

->  03 1b 43 48 43 0c 54 4f  4e 45 72 01 00 00 00 00
<-  [51 octets]

    [[ typical status response ]]

->  03 1b 43 48 43 0c 54 4f  4e 45 20
<-  [64 octets]

    81 01 07 07 27 07 72 07  c8 07 f8 07 22 07 48 08
    68 08 88 08 b3 08 db 08  f7 08 09 09 2e 09 49 09
    65 09 80 09 aa 09 ca 09  e2 09 fa 09 12 0a 32 0a
    42 0a 66 0a 81 0a 9a 0a  c3 0a d9 0a ee 0a 04 0b

->  03 1b 43 48 43 0c 54 4f  4e 45 20
<-  [64 octets]

  [[ repeats for total of 24 packets.  total of 1.5KiB. ]]

->  03 1b 43 48 43 0c 54 4f  4e 45 65 00 00 00 00 00
<-  [51 octets]

    [[ typical status response ]]

  Maybe this resets the calibration table:

->  03 1b 43 48 43 05 00 00  00 00 00 00 00 00 00 00 [???]
<-  [34 octets]

    01 00 04 00 00 00 01 00  01 00 02 00 00 00 01 00
    01 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
    00 00 

  Write tone curve data:

->  03 1b 43 48 43 0c 54 4f  4e 45 77 01 00 00 00 00
<-  [51 octets]

    [[ typical status response ]]

->  03 00 00 46 06 53 06 c0  06 07 07 37 07 5d 07 87 
    07 a1 07 c8 07 08 08 08  08 08 08 48 08 68 08 88
    08 a9 08 b9 08 d9 08 f9  08 12 09 2e 09 49 09 70
    09 89 08 99 09 ba 09 ca  08 da 09 0a 0a 24 0a 38
<-  [51 octets]

    [[ typical status response ]]

->  03 0a 53 0a 66 0a 81 0a ...
   ....
->  03 cf 38 0a 39 3d 39 79  39 96 39 b6 39 fb 39 01
    34 0a 34 08 3a 0c 1a 10  3a
<-  [51 octets]

    [[ typical status response ]]

  [[ total of 24 packets * 64, and then one final packet of 25: 1562 total. ]]
  [[ It apepars the extra 25 bytes are to compensate for the leading '03' on 
     each of the 25 URBs. ]]

  Also seen on the 6850:

DEBUG: readback: 01 02 03 00 00 00 01 00 00 01 5f 6f 00 01 5f 6f 00 00 00 09 00 02 90 44 00 00 00 55 00 03 02 90 00 01 02 1d 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
INIT/???
DEBUG: readback: 01 02 03 00 00 00 00 00 00 01 5f 6f 00 01 5f 6f 00 00 00 09 00 02 90 44 00 00 00 55 00 03 02 90 00 01 02 1d 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
??? 6x8c 
DEBUG: readback: 01 02 01 00 00 00 00 00 00 01 5f 6f 00 01 5f 6f 00 00 00 09 00 02 90 44 00 00 00 55 00 03 02 90 00 01 02 1d 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 



*/