Epson 1520 - Stylus Color Inkjet Printer, Service Manual

Page: 23 / 165

Product Description
Rev. A
1-15
1.3 Interfaces
1.3.1 Parallel Interface
1.3.1.1 Forward Channel Specifications
Transmission mode :8 bit parallel , IEEE-P1284 compatibility mode
Synchronization :/STROBE pulse
Handshaking :BUSY and /ACKNLG signal
Signal level :TTL compatible level (IEEE-P1284 Level 1 device)
Parameter Minimum Maximum Condition
VOH* - 5.5 V
VOL* -0.5 V -
IOH* - 0.32 mA VOH = 2.4 V
IOL* - 12 mA VOL = 0.4 V
CO - 50 pf
VIH - 2.0 V
VIL 0.8 V -
IIH - 0.32 mA VIH = 2.0 V
IIL - 12 mA VIL = 0.8 V
CI - 60 pf
Note) * : A low logic level on the Logic H signal is as follows:
2.0 V or less when the printer is powered off.
3.0 V or more when the printer is powered on.
The receiver shall provide an impedance equivalent to 7.5 K ohm top ground.
Adaptable connector :57-30360 (Amphenol) or equivalent
The BUSY signal is set high before setting either /ERROR low or PE high and held high until all these
signals return to the inactive state.
The BUSY signal is at high level in the following cases:
During data entry (see Figure 1-8. Data Transmission Timing below.)
When the input data buffer is full
While /INIT signal is at low level or during hardware initialization
During a printer error condition (See /ERROR signal)
During test printing
When the printer is in default setting mode
When the parallel interface is not selected
The ERROR signal is at low level when one of the following errors has occurred:
Printer hardware error (fatal error)
Paper-out error
Paper-jam error
Ink-out error
The PE signal is high level during paper-out error.
Table 1-15. Signal level of TTL Compatible (IEEE-1284 level 1 device)
DATA (n)
DATA
BUSY
0.5 us (min.) 0 (min.)
0 (min.)
5 us (type.) 0 (min.)
DATA (n+1)
STORBE
ACKNLG
0.5 us (min.)
0.5 us (min.)
Figure 1-8. Data Transmission Timing