CRM IV - Display data protocol

General The microprocessor receives messages on the asynchronous serial input. First, the message is checked for errors in transmission using the checksum. Then the processor decides whether the message is addressed to this station. Last the data bytes in the message are sent to the display, the synchronous output, the asynchronous output or as digits back to the exchange, depending on the command type. Serial format The serial format is 8 bit, no parity, 2 stop bits, 9600 baud. Message format The message consists of the following items:

• A start of record mark, one byte. Always 0xa5.
• Byte count. One byte giving the number of bytes in the rest of the record. The count starts at the next byte and includes the checksum byte at the end of the record.
• Address. Two bytes telling for who this record is intended. The most significant byte comes first.
• Command type. One byte telling what the message is about.
• Data. Up to 18 bytes of data.
• Checksum. One byte checksum of record, obtained by adding count byte, address bytes, command byte and data bytes, ignoring any carry.

Addresses The processor has three different address registers that it tries to match against the address of the incoming message:

• The 16 bit main address register that is loaded by a message. The register may be loaded by a message that requires a double pulse on the polarity of the cd wire. The register is set to 0xff00 after full reset.
• The 8 bit K-group address register that can be loaded by a message.

The address range of the incoming messages is divided as follows:

Address	Interpretation
0x0000 - 0xfbff	The address is compared directly with the 16 bit main address register.
0xfc00 - 0xfcff	The lower 8 bits are compared with the short address register.
0xfd00 - 0xfdff	The lower 8 bits are compared with the K-group address register.
0xfe00 - 0xfeff	The lower 8 bits are compared with the upper 8 bits of the main address register. The processor have 0xff00 in the main address register after reset so that 0xfeff is group broadcast to all processors whose main address register is not yet loaded.
0xfffe	Maskable broadcast to all processors.
0xffff	Unmaskable broadcast to all processors.

Commands

The command byte tell the processor what to do. Not all commands will be supported by all systems, refer to individual product specifications for details.

NOTE: special use on CRM III

Command	Action description
0x01	Write data in message to low address (control register of display). Wait for display to become ready for each byte.
0x02	Write data to high address (display RAM and character generator of display). Wait for display to become ready for each byte.
0x03	Write data in message to high address, but interpret values in the range 0x10 .. 0x1f as control codes. Wait for display to become ready for each byte.
0x04	Load the main address register with the two first data bytes of message if the processor has received two pulses on the PD7 pin within a short time (less than one second). This is a double flash in the station LED and the sequence on the PD7 pin is 1-0-1-0-1. The first 1 must be present when the message is processed, meaning that the LED must be off. Most significant byte is first data byte.
0x05	Load the first data byte as the K-group address.
0x06	Write data bytes in message to low address.
0x07	Write data bytes in message to high address.
0x08	HC05/HC04 specific command: Load the short address register from port A (PA0..PA7).
0x09	Mask broadcast. Messages with address 0xfffe is ignored.
0x0a	Unmask broadcast. Messages with address 0xfffe is recognised.
0x0b	HC05/HC04 specific command: Shift 0xff out to SPI address 0x02. This command is for compatibility with old version of display station processor only.
0x0c	HC05/HC04 specific command: Shift 0x00 out to SPI address 0x02. This command is for compatibility with old version of display station processor only.
0x0d	HC05/HC04 specific command: Shift first data byte out to address 0x00. This command is for compatibility with old version of display station processor only.
0x0e	HC05/HC04 specific command: Shift first data byte out to address 0x01. This command is for compatibility with old version of display station processor only.
0x20	HC05/HC04 specific command: Shift data in message out to specified SPI addresses. Data and addresses comes in pairs, first one byte of address then one byte of data. Since at most 18 bytes may be sent in one message, one message can load up to 9 external registers.
0x21	Transmit data bytes in message on asynchronous output (9600 baud, 2 stop bit, no parity, 8 bit data).
0x22	Use the data bytes in message as key presses, send them as digits on the CD wires. Key value 20 gives ID+specified current, key values 21-30 gives current pulse only, 31 gives C-key pulse.
0x23	Activate handset and volume override.
0x24	Deactivate handset and volume override.
0x25	Load the main address register with the two first data bytes of the message without looking for any pulses on CD-wire. Most significant byte is first data byte.
0x26	Activate RCO-pin (HC05: Active = PD1/TDO going low).
0x27	Deactivate RCO-pin (HC05: Inactive = PD1/TDO going high).
0x28	Activate RCO-pin with time-out given by data byte. Time-out is given by hex value times 100 ms. (HC05: Active = PD1/TDO going low).
0x29	Start pulse train on RCO-pin. First data byte gives on-time, second data byte gives off-time, and third data byte gives number of pulses (max 127 = 0x7f). Times are given by hex value times 100 ms. (HC05: on = PD1/TDO going low).
0x2a	HC05/HC04 specific command: Same as 0x22, but four-digit version number is appended.
0x2e	HC05/HC04 specific command: Activate watchdog reset, processor dials own identity (directory number) if programmed, when coming alive.
0x2f	Stop activities in microcontroller to start watchdog reset.
0x31	Multiple display version of command 0x01. Display address is first byte after command. Address 0x00 is default display (for back compatibility use command 0x01) and address 0xff is all displays.
0x32	Multiple display version of command 0x02. Display address is first byte after command. Address 0x00 is default display (for back compatibility use command 0x02) and address 0xff is all displays
0x33	Multiple display version of command 0x03. Display address is first byte after command. Address 0x00 is default display (for back compatibility use command 0x03) and address 0xff is all displays
0x41	Set indicator status command; will set status on one indicator as off, on, slow blink or fast blink. It will refer to KEY number(K), indicator number(I) and status selector with state(S). Many indicator can be set with one command: Example: 0x41+ KIS+KIS+….+KIS+ checksum (up to 9 KIS) Message ID: 0x41 : 1 byte Message size: 16 bits - Key number: 10 bits - Indicator number: 3 bits indicator 0 (binary 000): red LED indicator 1 (binary 001): green LED indicators 2-7: for future use - Status selector (*): 2 bits status 0, binary 00, low priority: on status 1, binary 01, medium priority: slow blink status 2, binary 10, high priority: fast blink status 3, binary 11, no priority for future use - Status state: 1 bit state off, binary 0 off state on, binary 1 on (*): Status with higher the priority will override the lower.<br\> NOTE: special indicator use on keys # 1000-1023
0x42	A station indicator reset command: <br\> It will reset all the indicators on the station to state 0. <br\> Message ID: 0x42<br\> The command has no parameters.
0x43	A station indicator test command (lamptest): <br\> It will divide the lamps into sections that will be sequentially set to state 1 (on) so that no more than ¼ of the lamps will light up at the same time. The function will stay active for a period set by a parameter.<br\> Message ID: 0x43 <br\> Parameter: time in seconds; 0-255.<br\> Example: “0x43+0x10+checksum” will stay active for 16 seconds

Special commands/usage

0x20 / 0x00 / 0b00ab cdef	CRM III special outputs:<br\> a,b,c,d,e: available extra outputs on CRM III display driver board (A100C01454), write ‘0’ if not used<br\> f : external buzzer (0=off, 1=on)
0x20 / 0x02 / 0b0000 abcd	CRM III special outputs: a : backlight control inverted (0=on, 1=off)<br\> b : internal buzzer (0=off, 1=on)<br\> c : do not use always write ‘0’<br\> d : do not use always write ‘0’ (display select)
0x41-43	Special indicator and status usage for keys 1000-up: key 1023: LCD backlight control - Indicator: indicator 0 (binary 000): backlight LCD 0 indicator 1 (binary 001): backlight LCD 1 indicator 2 (binary 010): backlight LCD 2 indicator 3 (binary 011): backlight LCD 3 indicator 4 (binary 100): backlight LCD 4 indicator 5 (binary 101): backlight LCD 5 indicator 6 (binary 110): backlight LCD 6 indicator 7 (binary 111): backlight LCD 7 -Indicator status as ordinary indicators. key 1022: Buzzer control - Indicator: indicator 0 (binary 000): internal buzzer indicator 1 (binary 001): external buzzer (relay) indicators 2-7: not used - Status selector (*): 2 bits status 0, binary 00, low pri: 1 blip every 5 sec status 1, binary 01, medium pri: 1 blip every 2 sec status 2, binary 10, high pri: on status 3, binary 11, no pri: for future use - Status state: 1 bit state off, binary 0 off state on, binary 1 on

Control codes as used in command 0x03

When sending a message with command 0x03, the processor writes the data bytes to the display high address. However, bytes in the range 0x10 to 0x1f is interpreted as control codes. The codes have the following meaning:

0x10	Clear display.
0x11	Move cursor to start of first line.
0x12	Move cursor to start of second line.
0x13	Position cursor. Use the following byte as the new cursor address. Range is 0x00..0x7f. Refer to HD44780 data sheet for details.
0x14	The following byte is written to low address rather than high address.
0x15	Mask broadcast. Messages with address 0xfffe will be ignored.
0x16	Unmask broadcast. Records with address 0xfffe will be recognised.

Dialling format, frequencies and currents.

The following format is used for key data in command type 0x22, for frequencies and for currents when dialling numbers:

Frequency	Current	Data byte in command 0x22	Name
500 Hz	Handset ON	0x00	Digit 0
700 Hz	Handset ON		Digit 1
900 Hz	Handset ON		Digit 2
1100 Hz	Handset ON		Digit 3
1300 Hz	Handset ON		Digit 4
1500 Hz	Handset ON		Digit 5
1700 Hz	Handset ON		Digit 6
1900 Hz	Handset ON		Digit 7
2100 Hz	Handset ON		Digit 8
2300 Hz	Handset ON		Digit 9
400 Hz	Handset ON	0x0a	Digit 10
2600 Hz	Handset ON		Digit 11
450 Hz	Handset ON		Digit 12
2900 Hz	Handset ON		Digit 13
600 Hz	Handset ON		Digit 14
3200 Hz	Handset ON		Digit 15
800 Hz	Handset ON		Digit 16
3600 Hz	Handset ON		Digit 17
1000 Hz	Handset ON		Digit 18
4000 Hz	Handset ON	0x13	Digit 19
500 Hz	M-key	0x20	M +digit 0
700 Hz	M-key		M +digit 1
900 Hz	M-key		M +digit 2
1100 Hz	M-key		M +digit 3
1300 Hz	M-key		M +digit 4
1500 Hz	M-key		M +digit 5
1700 Hz	M-key		M +digit 6
1900 Hz	M-key		M +digit 7
2100 Hz	M-key		M +digit 8
2300 Hz	M-key		M +digit 9
400 Hz	M-key	0x2a	M +digit 10
2600 Hz	M-key		M +digit 11
450 Hz	M-key		M +digit 12
2900 Hz	M-key		M +digit 13
600 Hz	M-key		M +digit 14
3200 Hz	M-key		M +digit 15
800 Hz	M-key		M +digit 16
3600 Hz	M-key		M +digit 17
1000 Hz	M-key		M +digit 18
4000 Hz	M-key	0x33	M +digit 19
500 Hz	Handset OFF	0x40	Hsoff +digit 0
700 Hz	Handset OFF		Hsoff +digit 1	900 Hz	Handset OFF		Hsoff +digit 2	1100 Hz	Handset OFF		Hsoff +digit 3	1300 Hz	Handset OFF		Hsoff +digit 4	1500 Hz	Handset OFF		Hsoff +digit 5	1700 Hz	Handset OFF		Hsoff +digit 6	1900 Hz	Handset OFF		Hsoff +digit 7	2100 Hz	Handset OFF		Hsoff +digit 8	2300 Hz	Handset OFF		Hsoff +digit 9	400 Hz	Handset OFF	0x4a	Hsoff +digit 10	2600 Hz	Handset OFF		Hsoff +digit 11	450 Hz	Handset OFF		Hsoff +digit 12	2900 Hz	Handset OFF		Hsoff +digit 13	600 Hz	Handset OFF		Hsoff +digit 14	3200 Hz	Handset OFF		Hsoff +digit 15	800 Hz	Handset OFF		Hsoff +digit 16	3600 Hz	Handset OFF		Hsoff +digit 17	1000 Hz	Handset OFF		Hsoff +digit 18	4000 Hz	Handset OFF	0x53	Hsoff +digit 19	500 Hz	C-key	0x60	C +digit 0	700 Hz	C-key		C +digit 1	900 Hz	C-key		C +digit 2	1100 Hz	C-key		C +digit 3	1300 Hz	C-key		C +digit 4	1500 Hz	C-key		C +digit 5	1700 Hz	C-key		C +digit 6	1900 Hz	C-key		C +digit 7	2100 Hz	C-key		C +digit 8	2300 Hz	C-key		C +digit 9	400 Hz	C-key	0x6a	C +digit 10	2600 Hz	C-key		C +digit 11	450 Hz	C-key		C +digit 12	2900 Hz	C-key		C +digit 13	600 Hz	C-key		C +digit 14	3200 Hz	C-key		C +digit 15	800 Hz	C-key		C +digit 16	3600 Hz	C-key		C +digit 17	1000 Hz	C-key		C +digit 18	4000 Hz	C-key	0x73	C +digit 19	(no tone)	M-key + ID	0x34	M+ID-pulse	(no tone)	Handset ON + ID	0x14	ID-pulse	(no tone)	Handset OFF + ID	0x54	Hsoff +ID-pulse	(no tone)	C-key + ID	0x74	C+ID-pulse	(no tone)	M-key	0x35	M-pulse	(no tone)	C-key	0x5f	C-pulse