Datasheet

56F8346 Technical Data, Rev. 15
42 Freescale Semiconductor
Preliminary
Figure 3-3 Connecting a Ceramic Resonator
Note: The OCCS_COHL bit must be set to 0 when a ceramic resonator is used. The reset condition on the
OCCS_COHL bit is 0. Please see the COHL bit in the Oscillator Control (OSCTL) register, discussed
in the 56F8300 Peripheral User Manual.
3.2.3 External Clock Source
The recommended method of connecting an external clock is illustrated in Figure 3-4. The external clock
source is connected to XTAL and the EXTAL pin is grounded. Set OCCS_COHL bit high when using an
external clock source as well.
Figure 3-4 Connecting an External Clock Register
3.3 Registers
When referring to the register definitions for the OCCS in the 56F8300 Peripheral User Manual, use the
register definitions without the internal Relaxation Oscillator, since the 56F8346/56F8146 devices do
NOT contain this oscillator.
Part 4 Memory Map
4.1 Introduction
The 56F8346 and 56F8146 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 memories are used in both spaces.
EXTAL XTAL
R
z
Sample External Ceramic Resonator Parameters:
R
z
= 750 KΩ
EXTAL XTAL
R
z
C1
CL1
CL2
C2
Resonator Frequency = 4 - 8MHz (optimized for 8MHz)
3 Terminal
2 Terminal
CLKMODE = 0
XTAL
EXTAL
External
V
SS
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.