Datasheet

Registers

56F8357 Technical Data, Rev. 15

Freescale Semiconductor 41

Preliminary

3.2.3 External Clock Source

The recommended method of connecting an external clock is given in Figure 3-4. The external clock

source is connected to XTAL and the EXTAL pin is grounded. When using an external clock source, set

the OCCS_COHL bit high as well.

Figure 3-4 Connecting an External Clock Signal

3.3 Registers

When referring to the register definitions for the OCCS in the 56F8300 Peripheral User Manual, use the

contain this oscillator.

Part 4 Memory Map

4.1 Introduction

The 56F8357 and 56F8157 devices are 16-bit motor-control chips based on the 56800E core. These parts

use a Harvard-style architecture with two independent memory spaces for Data and Program. On-chip

RAM and Flash memory are used in both spaces.

This chapter provides memory maps for:

• Program Address Space including the Interrupt Vector Table

• Data Address Space including the EOnCE Memory and Peripheral Memory Maps

On-chip memory sizes for each device are summarized in Table 4-1. Flash memories’ restrictions are

identified in the “Use Restrictions” column of Table 4-1.

Note: Data Flash and Program RAM are NOT available on the 56F8157 device.

Table 4-1 Chip Memory Configurations

On-Chip Memory 56F8357 56F8157 Use Restrictions

Program Flash 256KB 256KB Erase / Program via Flash interface unit and word writes to CDBW

Data Flash 8KB — Erase / Program via Flash interface unit and word writes to CDBW.

Data Flash can be read via one of CDBR or XDB2, but not both

simultaneously

Program RAM 4KB — None

Data RAM 16KB 16KB None

Program Boot Flash 16KB 16KB Erase / Program via Flash Interface unit and word to CDWB

XTAL

EXTAL

External

Clock

Note: When using an external clocking source with

this configuration, the input “CLKMODE” should be

high and the COHL bit in the OSCTL register

should be set to 1.