Canon Color Bubble Jet BJC-5000 Series, Service Manual

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2.1.3 ECP mode
In the ECP mode, the printer transfers 8-bit data all at once and therefore it can send
and receive data in high speed. This mode is suitable for sending and receiving large
volumes of data.
When the AckReverse signal goes from HIGH to LOW in response the ReverseReq
signal going from HIGH to LOW, the data bus direction changes from forward data
transfer (which sends data from host computer to printer) to reverse data transfer
(which sends data from printer to host computer).
During the reverse data transfer phase, the printer makes HostAck go from HIGH to
LOW when it detects the rising edge of PeriphClk.
When the host computer is able to receive data from the printer, HostAck goes from
HIGH to LOW; and when it receives data, HostAck goes from LOW to HIGH.
(The falling edge indicates a LOW and the rising edge indicates a HIGH.)
4-9
BJC-5000
Part 4: Technical Reference
0001 0000
1284 Active
Host Ack
Host Clk
Periph Clk
Xflag
TP
TP TP
Byte0
Byte1
nCmd nCmd
TP
TP: Minimum setting
ECP mode support
Data(1~8)
Ack Reverse
Periph Ack
Periph Req
Figure 4-9 Interface Timing (ECP Mode)