TMS470R1A288PGEA Datasheet, PDF (34/62 Pages) Texas Instruments – 16/32-Bit RISC Flash Microcontroller

TMS470R1A288
16/32-Bit RISC Flash Microcontroller
SPNS106B – SEPTEMBER 2005 – REVISED AUGUST 2006
www.ti.com
External Reference Resonator/Crystal Oscillator Clock Option
The oscillator is enabled by connecting the appropriate fundamental 4-10 MHz resonator/crystal and load
capacitors across the external OSCIN and OSCOUT pins as shown in Figure 6a. The oscillator is a single-stage
inverter held in bias by an integrated bias resistor. This resistor is disabled during leakage test measurement
and HALT mode. TI strongly encourages each customer to submit samples of the device to the
resonator/crystal vendors for validation. The vendors are equipped to determine what load capacitors will
best tune their resonator/crystal to the microcontroller device for optimum start-up and operation over
temperature/voltage extremes.
An external oscillator source can be used by connecting a 1.8-V clock signal to the OSCIN pin and leaving the
OSCOUT pin unconnected (open) as shown in Figure 6b.
OSCIN
OSCOUT
OSCIN
OSCOUT
C1^(A)
Crystal
C2^(A)
External
Clock Signal
(toggling 0-1.8 V)
(a)
(b)
A. The values of C1 and C2 should be provided by the resonator/crystal vendor.
Figure 6. Crystal/Clock Connection
34
Submit Documentation Feedback