Table of Contents
Advertisement
7
PRINTER OPERATION AND PROGRAMMING
The Ap863 has an EPSON M-T102 printer mechanism, with a fixed (parallel) print head with 384
horizontally-arranged thermal elements. The paper is advanced by a stepper motor, and printing
takes place in a single dot row for each step of the paper. Each printed dot is approximately 1/8 mm
square. The printing speed and dot density are controlled according to the battery voltage and the
head temperature.
Alternative printing modes, including graphics, are invoked by 'Escape' sequences. Control codes
and status report protocols are described in detail in the Programmers' Guide, available as a separate
document.
7.1
DATA BUFFER
The Ap863 has a nominal 20k byte buffer to optimise throughput: this enables data to be received into
the buffer while previous lines are being printed. Printing will be initiated on receipt of a valid logical
line of data or a complete graphics pattern.
The buffer may be cleared by data command or by a hardware reset. A partially full line will be
printed on receipt of an appropriate control code, or after a programmable timeout delay.
7.2
SPOOLING MODE
Spooling mode can be entered under command from the host. It can also be programmed to be
entered automatically when the paper runs low, or completely out. This makes it easier to change the
roll without losing data (refer to Section 5).
In spooling mode, the buffered data are stored without being printed until the mode is exited by:
Ÿ
a command from the host;
Ÿ
the paper feed button being double-clicked.
7.3
SERIAL INTERFACE (STANDARD RS-232 VERSION)
The serial interface Baud rate is factory set to 9,600 Baud, and the data format should be 8 data bits,
1 or 2 stop bits, and no parity (see Section 8 for connection details); other baud rates can be
programmed by control codes. Serial data is expected in standard RS-232C format with -12V
meaning 'mark' or '1' and +12V a logical '0', with reference to the common ground. The serial data
output line, TxD, transmits XON/XOFF and status information to the host at the same Baud rate and
in the same format as the serial data input. The hardware busy line is true (nominal -12V) when busy.
Both serial output lines will relax to approximately 0V when the Ap863 is in sleep mode, and the user
must allow a short period after awakening before relying on the values of these signals.
Some host equipment use a constant space condition (+12V) to indicate a reset condition or wait
state. Some battery powered host equipment present the same output signal when they go to sleep.
The Ap863 can be set to ignore this condition as detailed in the Programmer's Guide, but even then
this type of host behaviour may result in one or more spurious characters being received by the
Ap863, or the Ap863 may be prevented from going to sleep.
7.4
SERIAL INTERFACE (TTL VERSION)
As an option the Ap863 may be ordered with a TTL serial interface. In this version, the data format is
identical to the RS-232 version described above. However, the voltage levels are different.
Serial data is expected on RxD in TTL format with +5V meaning 'mark' or logical '1', and 0V meaning
'space' or logical '0', with reference to the common ground. The serial data output line, TxD, transmits
XON/XOFF and status information to the host at the same baud rate and format as the serial data
input. The hardware busy line, Busy, is true (nominally +5V) when busy. Both serial output lines will
relax to approximately 0V when the Ap863-TTL is in sleep mode, and the user must allow a short
period after awakening before relying on the values of these signals.
Some host equipment use a constant space condition (0V) to indicate a reset condition or wait state.
Some battery powered host equipment present the same output signal when they go to sleep. The
Ap863-TTL can be set to ignore this condition as detailed in the Programmer's Guide, but even then
this type of host behaviour may result in one or more spurious characters being received by the
Ap863-TTL.
Ap863 Users' Guide Page 13 of 18
Advertisement
Table of Contents
