
26
PARALLEL DATA SIGNAL
• Parallel input connector port
Signal allocation (Signal : Nibble)
Pin No.
1
2 - 9
10
11
12
13
14
16 • 17
18
19 - 30
31
32
15•
33 - 35
36
Return pin No.
19
20 - 27
28
29
16
Signal
HostClk
Unknown
PtrBusy
PtrBusy
AckDataReq
Xflag
HostBusy
GND
High
GND
Init
DataAvail
NC
1284 Active
From/To
PC/VCP
PC/VCP
PC/VCP
PC/VCP
PC/VCP
PC/VCP
PC/VCP
PC/VCP
PC/VCP
PC/VCP
PC/VCP
Function
High
Unknown
Sends data in “Low” when HostBusy is “Low”. After HostBusy
turns “High”, this signal becomes “High”.
Data4, Data8 (MSB)
Data3, Data7
Data2, Data6
High : VCP is on BUSY status.
Low : VCP can send data.
Earth
PeripheralLogicHigh
Earth
Clears sending data to this unit. (Low) Incoming pulse width
should be 100
µ
s minimum.
Data1(LSB), Data5
Unused
Becomes “High” when VCP requests each mode of IEEE1284.