Hp 220 Uživatelský manuál stáhnout pdf (Strana 57)

5Ć25 Functional OverviewC3187Ć90000

  The main processor controls the DTR (Data Terminal Ready) signal using

a bit in the parallel I/O control register. Whenever the power to the plotter is on, RTS

(Request To Send) is set active. No other modem signals are controlled or monitored.

   The reset state of the DTR signal is undefined. During

initialization, the main processor first sets the DTR control bit to 1, which signals the host

that the interface cannot accept data. Later the processor sets the UART configuration



Two MBytes of DRAM for system use and I/O data storage reside permanently on the Main

PCA. In addition, a 72Ćpin socket for the industryĆstandard DRAM SIMM is provided for

optional memory. The socket supports a DRAM SIMM of 2 MB, 4 MB, or 8 MB.

   

PowerĆon reset signals are used to initialize the processorĆsupport ASIC, shuffler ASIC and

servo processor. The processor support ASIC generates a reset signal to initialize the main

processor. A powerĆon reset signal disables the EEROM to prevent loss of data during power

transitions. The components that generate the reset signals guarantee valid signals once the

logic supply (+5V) exceeds 2.0 V.

1 2 ... 52 53 54 55 56 57 58 59 60 61 62 ... 245 246

Žádné komentáře

Hp 220 Uživatelský manuál Strana 57