ST72F621J4B1 STMicroelectronics, ST72F621J4B1 Datasheet - Page 115

• Manufacturer Part Number: ST72F621J4B1
• Description: IC MCU 8BIT LS 16K 42-PDIP
• Manufacturer: STMicroelectronics
• Series: ST7r

Specifications of ST72F621J4B1

• Core Processor: ST7
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: SCI, SPI, USB
• Peripherals: DMA, LVD, POR, PWM, WDT
• Number Of I /o: 31
• Program Memory Size: 16KB (16K x 8)
• Program Memory Type: FLASH
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 42-DIP (0.600", 15.24mm)
• Processor Series: ST72F6x
• Core: ST7
• Data Bus Width: 8 bit
• Data Ram Size: 768 B
• Interface Type: SCI, SPI, USB
• Maximum Clock Frequency: 12 MHz
• Number Of Programmable I/os: 31
• Number Of Timers: 2
• Operating Supply Voltage: 4 V to 5.5 V
• Maximum Operating Temperature: + 70 C
• Mounting Style: Through Hole
• Minimum Operating Temperature: 0 C
• On-chip Adc: 10 bit
• For Use With: 497-5046 - KIT TOOL FOR ST7/UPSD/STR7 MCU
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: In Transition
• Other names: 497-2110-5

CONTROL PIN CHARACTERISTICS (Cont’d)
Figure 75. RESET pin protection when LVD is enabled.
Figure 76. RESET pin protection when LVD is disabled.
Note 1:
Note 2: When the LVD is enabled, it is recommended not to connect a pull-up resistor or capacitor. A 10nF pull-down
capacitor is required to filter noise on the reset line.
Note 3: In case a capacitive power supply is used, it is recommended to connect a 1MΩ pull-down resistor to the RESET
pin to discharge any residual voltage induced by the capacitive effect of the power supply (this will add 5µA to the power
consumption of the MCU).
Note 4: Tips when using the LVD:
EXTERNAL
Required
– The reset network protects the device against parasitic resets.
– The output of the external reset circuit must have an open-drain output to drive the ST7 reset pad. Otherwise the
– Whatever the reset source is (internal or external), the user must ensure that the level on the RESET pin can go
– Because the reset circuit is designed to allow the internal RESET to be output in the RESET pin, the user must en-
– 1. Check that all recommendations related to the reset circuit have been applied (see notes above).
– 2. Check that the power supply is properly decoupled (100nF + 10µF close to the MCU). Refer to AN1709 and
– 3. The capacitors connected on the RESET pin and also the power supply are key to avoid any start-up marginality.
EXTERNAL
RESET
CIRCUIT
device can be damaged when the ST7 generates an internal reset (LVD or watchdog).
below the V
internally.
sure that the current sunk on the RESET pin is less than the absolute maximum value specified for I
section 12.2.2 on page
AN2017. If this cannot be done, it is recommended to put a 100nF + 1MΩ pull-down on the RESET pin.
In most cases, steps 1 and 2 above are sufficient for a robust solution. Otherwise: replace 10nF pull-down on the
RESET pin with a 5µF to 20µF capacitor.”
RESET
USER
Required
IL
max. level specified in
0.01μF
0.01μF
102.
1MΩ
Optional
(note 3)
section 12.9.1 on page
V
V
Doc ID 6996 Rev 5
DD
DD
R
R
ON
ON
Filter
Filter
113. Otherwise the reset will not be taken into account
1)2)3)4)
1)
GENERATOR
PULSE
GENERATOR
PULSE
WATCHDOG
WATCHDOG
ILLEGAL OPCODE
LVD RESET
ILLEGAL OPCODE
INTERNAL
RESET
INTERNAL
RESET
INJ(RESET)
ST72XXX
ST72XXX
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5)
5)
in