Precautions - Citizen CBM-1000 User Manual

13.2.3 Precautions

1) The Negotiation phase is triggered when the IEEE 1284 Active signal sent by the
host becomes High.
2) In Compatibility mode, the time when the negotiation process begins is, as a
general rule, after the host sets nStrobe to High and then the printer outputs an
nAck pulse.
Once the nStrobe signal is set to High, however, the printer immediately moves
into the Negotiation phase when the high state of IEEE 1284 Active is detected,
even if the nAck pulse has yet to be output or is being output. In this case, if the
printer has returned to Compatibility mode after Termination, no nAck pulse will
be output.
3) Negotiations can be entered from the Busy or Error state of the Compatibility
mode. In this case, the printer will not return to the Busy or Error state before
the negotiations, but still remains in the printer state just after Termination.
4) If the host requested a communication mode that is not supported by the
printer, it must move into the Termination phase and return to the Compatibility
mode.
Table 2.4.1 Definitions of Request Bits in IEEE 1284 Communication Mode
Bit
7 Request Extensibility Link
6 Request EPP Mode
5 Request ECP Mode with RLE
4 Request ECP Mode
3 Reserve
Request Device ID: Return Data Using
Nibble Mode Rev Channel Transfer
2 Byte Mode Rev Channel Transfer
ECP Mode Transfer without RLE
ECP Mode Transfer with RLE
1 Reserve
0 Byte Mode Reverse Channel Transfer
None Nibble Mode Reverse Channel Transfer 00000000
Illegal or Contradictory Request
Note: The printer only supports the Nibble and Byte modes. For a request for any
other mode, Xflag is set to Low.
Definition
—163 —
Bit Values
Hex.
(76543210)
10000000 80H
01000000 40H
00110000 30H
00010000 10H
00001000 08H
00000100 04H
00000101 05H
00010100 14H
00110100 34H
00000010 02H
00000001 01H
00H
Other than Other than
above above
Xflag
When In the
supported printer
High Low
High Low
High Low
High Low
High Low
High High
High High
High Low
High Low
High Low
High High
Low Low
— Low