Samsung MSYS 5150, Руководство по обслуживанию

Страница: 53 / 210

Circuit Description
Fig.5-5 Compatibility Hardware handshaking Timing
1. Write the data to the data register.
2. Program reads the status register to check that the printer is not BUSY.
3. If not BUSY, then Write to the Control Register to assert the STROBE line.
4. Write to the Control register to de-assert the STROBE line.
Fig.5-6 ECP Hardware Handshaking Timing (forward)
1. The host places data on the data lines and indicates a data cycle by setting nAUTOFD.
2. Host asserts nSTROBE low to indicate valid data.
3. Peripheral acknowledges host by setting BUSY high.
4. Host sets nSTROBE high. This is the edge that should be used to clock the data into the Peripheral.
5. Peripheral sets BUSY low to indicate that it is ready for the next byte.
6. The cycle repeats, but this time it is a command cycle because nAUTOFD is low.
Samsung Electronics 5-5