II CORE BLOCK: CLG (Clock Generator)

I/O Pins of Clock Generator

Table 6.1 lists the I/O pins of the clock generator.

 

 

 

 

 

Table 6.1 I/O Pins of Clock Generator

 

Pin name

I/O

 

 

 

 

Function

 

OSC3

I

High-speed (OSC3) oscillation input pin

 

 

 

 

 

Crystal/ceramic oscillation or external clock input

 

OSC4

O

High-speed (OSC3) oscillation output pin

 

 

 

 

 

Crystal/ceramic oscillation (open when external clock is used)

 

PLLC

–

Capasitor connecting pin for PLL

 

 

 

PLLS[1:0]

I

PLL set-up pins

 

 

 

 

 

 

 

PLLS1

PLLS0

fin (fOSC3)

fout (fPSCIN)

 

 

 

 

 

1

1

10–25MHz

20–50MHz

 

∗ 1

 

 

 

0

1

10–12.5MHz

40–50MHz

 

∗ 1

 

 

0

0

PLL is not used

L

∗ 2

 

 

∗ 1: ROM-less model with 3.3 V ± 0.3 V operating voltage

 

 

 

∗ 2: When the PLL is not used, the OSC3 clock is used directly.

 

High-Speed (OSC3) Oscillation Circuit

The high-speed (OSC3) oscillation circuit generates the main clock for the CPU and internal peripheral circuits (e.g., DMA, serial interface, programmable timer, and A/D converter).

This circuit can be a crystal or a ceramic oscillation circuit. Optionally an external clock source can be used. Figure 6.2 shows the structure of the high-speed (OSC3) oscillation circuit.

CG2

OSC3

 

OSC3

 

 

VDD

 

 

X'tal2

fOSC3

VSS

fOSC3

Rf

 

External

 

or

 

clock

 

 

Ceramic

 

 

 

 

 

Oscillation circuit

N.C.

Oscillation circuit

 

OSC4

control signal

control signal

CD2

OSC4

 

SLEEP status

SLEEP status

VSS

 

 

 

 

 

 

(1) Crystal/ceramic oscillation circuit

 

(2) External clock input

Figure 6.2 High-Speed (OSC3) Oscillation Circuit

When using a crystal or a ceramic oscillation for this circuit, connect a crystal (X'tal2) or ceramic (Ceramic) resonator and feedback resistor (Rf) between the OSC3 and OSC4 pins, and two capacitors (CG2, CD2) between the OSC3 pin and VSS and the OSC4 pin and VSS, respectively.

When an external clock is used, leave the OSC4 pin open and input a square-wave clock to the OSC3 pin.

The range of oscillation frequencies is 10 MHz to 33 MHz. This frequency range also applies when an external clock is used.

Note: When using the PLL, the oscillation frequency range changes according to the PLL setting. See Table 6.2.

For details on oscillation characteristics and the external clock input characteristics, refer to "Electrical Characteristics".

B-II-6-2

EPSON

S1C33L03 FUNCTION PART