MC68340 datasheet(391/441 Pages) FREESCALE

391 / 441 page

10-4

MC68340 USER’S MANUAL

MOTOROLA

load capacitance on the chip-select (

≈) signal is not exceeded. (Address buffers may

be needed, however.)

10.1.4 ROM Interface

Using the programmable chip selects creates a very straightforward ROM interface. As

shown in Figure 10-6, no external circuitry is needed. Care must be used, however, not to

overload the address bus. Address buffers may be required to ensure that the total system

input capacitance on the address signals does not exceed the CL specification.

MC68340

A16–A1

D15–D0

CS0

16-BIT

ROM

Figure 10-6. ROM Interface

10.1.5 Serial Interface

The necessary circuitry to create an RS-232 interface with the MC68340 includes an

external crystal and an RS-232 receiver/driver (see Figure 10-7). The resistor and

capacitor values shown are typical; the crystal manufacturer's documentation should be

consulted for specific recommendations on external component values. The circuit shown

does not include modem support (ready-to-send (RTS) and clear-to-send (CTS) are not

shown); however, these signals can be connected to the receiver/driver and to the

connector in a similar manner as the connections for TxDx and RxDx.

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

MC68340 Datasheet(PDF) 391 Page - Freescale Semiconductor, Inc