ST7263BK4 STMicroelectronics, ST7263BK4 Datasheet - Page 44

• Manufacturer Part Number: ST7263BK4
• Description: LOW SPEED USB 8-BIT MCU FAMILY WITH UP TO 32K FLASH/ROM, DFU CAPABILITY, 8-BIT ADC, WDG, TIMER, SCI and I2C
• Manufacturer: STMicroelectronics

Specifications of ST7263BK4

• 4, 8, 16 Or 32 Kbytes Program Memory: high density Flash (HDFlash), FastROM or ROM with Read-Out and Write protection

I/O ports
Note:
Note:
Caution:
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Output mode
The pin is configured in output mode by setting the corresponding DDR register bit (see
Table 7).
In this mode, writing “0” or “1” to the DR register applies this digital value to the I/O pin
through the latch. Therefore, the previously saved value is restored when the DR register is
read.
The interrupt function is disabled in this mode.
Digital alternate function
When an on-chip peripheral is configured to use a pin, the alternate function is automatically
selected. This alternate function takes priority over standard I/O programming. When the
signal is coming from an on-chip peripheral, the I/O pin is automatically configured in output
mode (push-pull or open drain according to the peripheral).
When the signal is going to an on-chip peripheral, the I/O pin has to be configured in input
mode. In this case, the pin’s state is also digitally readable by addressing the DR register.
Input pull-up configuration can cause an unexpected value at the input of the alternate
peripheral input.
When the on-chip peripheral uses a pin as input and output, this pin must be configured as
an input (DDR = 0).
The alternate function must not be activated as long as the pin is configured as an input with
interrupt in order to avoid generating spurious interrupts.
Analog alternate function
When the pin is used as an ADC input the I/O must be configured as a floating input. The
analog multiplexer (controlled by the ADC registers) switches the analog voltage present on
the selected pin to the common analog rail which is connected to the ADC input.
It is recommended not to change the voltage level or loading on any port pin while
conversion is in progress. Furthermore it is recommended not to have clocking pins located
close to a selected analog pin.
Warning:
The analog input voltage level must be within the limits
stated in the absolute maximum ratings.
Doc ID 7516 Rev 8
ST7263Bxx