HMS87C13042A Datasheet, PDF (42/88 Pages) Hynix Semiconductor – 8-BIT SINGLE-CHIP MICROCONTROLLERS

HMS87C130XA/120XA/110XA
oscillator frequency is a function of the supply voltage, the
external resistor (R_EXT) and capacitor (C_EXT) values, and
the operating temperature.
The user needs to take into account variation due to toler-
ance of external R and C components used.
Figure 10-4 shows how the RC combination is connected
to the HMS87C1X0XA.
Vdd
R_EXT
X_IN
C_EXT
Cint ≈ 6pF
f_XIN÷4
X_OUT
Figure 10-4 RC Oscillator Connections
External capacitor (C_EXT) can be omitted for more cost
saving. However, the characteristics of external R only os-
cillation are more variable than external RC oscillation.
V_DD
R_EXT
X_IN
C_INT ≈ 6pF
f_XIN÷4
X_OUT
Figure 10-5 R Oscillator Connections
The oscillator frequency, divided by 4, is output from the
Xout pin, and can be used for test purpose or to synchroze
other logic.
To set the RC oscillation, it should be programmed
RCOPT bit to "1" to CONFIG (707F_H). ( Refer to Section
"20.1". )
Apr. 2001 ver1.0
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