Sony UP-D2600, Service Manual

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4-3
UP-D2600/V1(E)
[IEEE-1284 (Be-directional Parallel=Bi-Centronics) Interface Circuit]
(UP-D2600 only)
IC209 controls the operation modes of the IEEE-1284 interface. It performs such operations as shifting to
the mode required for communication according to the setting of the register from system controller
IC204 and data transmission/reception.
IC205 and IC206 is a bi-directional driver IC which conforms to the IEEE-1284 standards, while IC207 is
the buffer IC of the control line.
The data input from the host computer via CN201 is inputted to IC209 via the IC205 through IC207
buffer. IC209 activates the interrupt signal (pins 1 through 3, the role differs according to the mode) for
every 1 byte of data, and notifies the system controller IC204 if the data is the command data, and notifies
the memory controller IC102 if the data is the image data. Upon receiving this interrupt signal, IC204
and IC102 read the data using the RD signal. IC204 also writes the data in IC209 according to the earlier
mentioned interrupt signal even when sending the data from the printer to the host computer.
4-1-3. DRAM and Memory Control Circuit
IC102 is a memory control gate array. Its main functions are as follows:
UP-D2600S
.
Image data is written in DRAMs IC107, IC108 and IC111 by one byte to one byte should the DMA bus
(pins 2 to 8 of IC102) input from IC209. The handshake with IC209 is performed at DREQ and DACK
(pins 156 through 158). Receiving control line DMAEN (pin 111) from IC204, DMA transmission is
performed while DMABSY (pin 115) is active.
UP-D2600
.
The data bus input from IC209 is assigned to the command data and image data bus by the setting from
system control CPU IC204. For the command data, the data bus is directly connected to IC204. Under
control line DMAEN (pin 111) from IC204, it is set to the image data bus while DMABSY (pin 115) is
active. In this case, under the interrupt operation (pins152 to 154) from IC209, the image data is
written in DRAMs IC107 and IC108 one byte at a time by external synchronization. (DMA transfer)
.
During printing, the data is read one byte at a time from the DRAM IC107 and IC108 by the internal
synchronization, arranged to 3 bytes for R, G, and B, and sent to the color adjustment IC. (Pins 51
through 58, 61 through 68, and 71 through 78.)
.
The test pattern set for the register is written in the DRAM by the internal synchronization.
.
DRAM refresh operations (RAS only refresh) are performed by the cycle set by the register.
IC110 assigns each image plane of R, G, and B to IC107, IC108, and IC111, respectively.