MC68SC302 PRODUCT INFORMATION

• Other System Integration Features

— Flexible Pin Configuration Allows Trade-Offs between 16-Bit Wide ISA/PC Card Interface and Extra

I/O Pins.

• Up to 16 Parallel I/O Pins for Controlling Other Functions.

— On-Chip Interrupt Controller

• 8 Internal Interrupt Sources

• 7 External Pin Sources for External Devices.

— 2 Low-Power Modes

• Wait - Oscillator Keeps Running ~5 mA

• Stop - Oscillator Stops - <100uA

— Operating Speed: 0-20.48 Mhz

— Operating Voltage: 5V

— 100 pin TQFP (14mm x 14mm)

MC68SC302 OVERVIEW

The block diagram for the MC68SC302 is shown in Figure 1. The MC68SC302 architecture is based on a

microcoded RISC communications processor that services the three main high speed serial channels (SCC),

two serial management channels (SMC) and a serial communications port (SCP). The three SCC channels

support simultaneous operation of the three channels specified by the ISDN basic rate interface (2B+D). Each

SCC can support onboard HDLC processing as well as totally transparent operation. The dual-port RAM

provides 1536 bytes of memory. A maximum of 1280 bytes can be allocated for serial channel buffer space,

which, when allocated evenly for a basic rate interface, allows 256 bytes per B channel per direction and 64

bytes per direction for the D channel. This provides 32msec worth of basic rate data to be stored in the buffers,

allowing ample interrupt latency time for host platform operating systems. The IDL or GCI interface provides

direct connection to the Freescale MC145572 U interface transceiver, the MC145574 S/T interface transceiver,

and other popular ISDN transceivers. A non-multiplexed serial interface (NMSI) is also provided for SCC2.

The MC68SC302 has an ISA Plug and Play interface which supports the ISA Plug and Play specification

version 1.0a. The ISA bus interface can be configured for either I/O mode accesses or memory mode

accesses. The ISA interface can be either an 8- or 16-bit wide data bus allowing pin usage trade-offs to be

made. I/O mode accesses are based on a self-incrementing pointer, allowing the PC to write or read data from

a fixed ISA I/O address. Memory mode access allows the PC to write or read data into a predefined ISA

window. In addition to supporting access to the internal MC68SC302 register and memory map, an additional

chip-select is provided for an external device, and can be programmed for either memory or I/O and either 8

or 16 bit bus independent of internal space.

The MC68SC302 can also be configured to provide a PC Card interface based on the PC Card 95

specification. Either 8- or 16-bit wide memory cards can be implemented. There are two options available for

supporting the Card Information Structure (CIS): 1)The CIS can be stored in external serial EEPROM which is

downloaded on reset into the Dual Port RAM (DPRAM) space. 2) To save DPRAM space, the CIS can be

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com