Figure 2-26. Dma Controller Operation - Epson 4003353 Service Manual

Operating Prhcip/es
Stylus Color Service Manual
2.3.2.6
Data from the host computer is received automatically by the /STB signal via the external
Centronics interface. The data is input into the input buffer on the D-RAM (IC5). At this time,
sends a bus request to the bus controller in the CPU, and then the CPU releases the bus line. Due to
this, the external data is transported into the memory, bypassing the CPU.
CPU H8 (ICI)
132 9
STBDMA
, --------------- .--------------,
4
ACK
Memory
BAC
'. . . . . . . .
BUSY

Figure 2-26. DMA Controller Operation

Rev. A
2-21