ST72C334N2B6 STMicroelectronics, ST72C334N2B6 Datasheet - Page 30

• Manufacturer Part Number: ST72C334N2B6
• Description: Microcontrollers (MCU) Flash 8K SPI/SCI
• Manufacturer: STMicroelectronics

Specifications of ST72C334N2B6

• Data Bus Width: 8 bit
• Program Memory Type: Flash
• Program Memory Size: 8 KB
• Data Ram Size: 384 B
• Interface Type: SCI, SPI
• Maximum Clock Frequency: 8 MHz
• Number Of Programmable I/os: 44
• Number Of Timers: 16 bit
• Operating Supply Voltage: 3.2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• Package / Case: SDIP-56
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8 bit
• Lead Free Status / Rohs Status: No

ST72334J/N, ST72314J/N, ST72124J
MULTI-OSCILLATOR (MO)
The main clock of the ST7 can be generated by 7
different sources coming from the multi-oscillator
block:
Each oscillator is optimized for a given frequency
range in terms of consumption and is selectable
through the OPTION BYTE.
External Clock Source
The default OPTION BYTE value selects the Ex-
ternal Clock in the MO block. In this mode, a clock
signal (square, sinus or triangle) with ~50% duty
cycle has to drive the OSC1 pin while the OSC2
pin is tied to ground (see Figure 19).
Figure 19. MO External Clock
30/125
an external source
4 crystal or ceramic resonator oscillators
1 external RC oscillator
1 internal high frequency RC oscillator
EXTERNAL
SOURCE
OSC1
ST7
OSC2
Crystal/Ceramic Oscillators
This family of oscillators has the advantage of pro-
ducing a high accuracy on the main clock of the
ST7. The selection within a list of 4 oscillators with
different frequency ranges has to be done by OP-
TION BYTE in order to reduce the consumption. In
this mode of the MO block, the resonator and the
load capacitances have to be connected as shown
in Figure 20 and have to be mounted as close as
possible to the oscillator pins in order to minimize
output distortion and start-up stabilization time.
The loading capacitance values must be adjusted
according to the selected oscillator.
These oscillators, when selected via the OPTION
BYTE, are not stopped during the RESET phase
to avoid losing time in the oscillator start-up phase.
Figure 20. MO Crystal/Ceramic Resonator
C
L0
OSC1
CAPACITANCES
LOAD
ST7
OSC2
C
L1