XJ128 and XJ128 Plus Printhead
XJ128 Guide to Operation
Xaar Document no: D031010302 Version A
Page 25
TEST_0 - TEST_9
All inputs not required for the operation of the XJ128 printhead. Should not be connected.
TEST_10
No function. But, input must be tied high to VDD (+5V).
If there is any risk that TEST_10 may have dropped to a low level state, then the nRESET signal
must immediately be activated (low level) to make the printhead return to correct operating mode.
SCK
Also referred to with other XJ printheads as
‘
data
-strobe
’
. Data is clocked into the shift register on the
leading edge of the SCK, and clocked out of the shift register on the falling edge of the SCK. 128
load operations are required to completely fill a printhead with pixel data. Data clocked into the head
after the 128th DSTB and before nFIRE, will cause the first data loaded to be lost. The maximum
frequency of SCK pulses is 2MHz. Print data can be loaded for the next pixel whilst the previous
pixel is being printed.
nFIRE
Active low. Level sensitive input used to
‘
fire
’
the print head. The nFire signal can be activated
independent of whether print data has been loaded or not.
READY
Active high. An output indication that two of the three-phase firing sequence is complete. Since the
transmission of data is allowed two clock cycles after nFire, this signal does not mean that the head
is busy, but is used as a timing pulse so the system can stay synchronised. nFIRE is sampled while
READY is active (high level).
PHO
Active high. This signal determines the phase order. When active, the phase order is C-B-A and
inactive, the phase order is A-B-C. This signal has the same set-up and hold requirements as nFIRE.
MISO
Master In-Slave Out or Serial out data line. Connected to the most significant bit, i.e. bit 63 of the
internal shift register. This signal is a tri-state output signal. The output is controlled by nSS1 and
nSS2. This is used when daisy-chaining printheads to shift data from one printhead to another.
CLK
A state-machine clock that drives the driver chip state-machine and synchronisation logic. Should be
set to 1MHz. Also referred to with other XJ printheads as
‘
sample clock
’
.
5.4 Electrical connection to the printhead
The electrical interface connector is a 30-pin connector. The printhead interface makes use of an
AMP
™
connector type:
“
AMP
™
30 pin receptacle board
-to-board connector
”
. The AMP
™
part
number for the printhead connector is: 6-176913-0 (female).