ST10F272B_12 STMICROELECTRONICS [STMicroelectronics], ST10F272B_12 Datasheet - Page 20

• Manufacturer Part Number: ST10F272B_12
• Description: 16-bit MCU with 256 Kbyte Flash memory and 12/20 Kbyte RAM
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Pin data
Table 1.
20/188
P0L.0 -P0L.7,
EA / V
Symbol
P0H.1 -
P0H.0
P0H.7
STBY
Pin description (continued)
100-107,
111-117
108,
Pin
99
Type
I/O
I
External access enable pin.
A low level applied to this pin during and after Reset forces the ST10F272 to start
the program from the external memory space. A high level forces ST10F272 to
start in the internal memory space. This pin is also used (when Stand-by mode is
entered, that is ST10F272 under reset and main V
kHz oscillator amplifier circuit and to provide a reference voltage for the low-
power embedded voltage regulator which generates the internal 1.8V supply for
the RTC module (when not disabled) and to retain data inside the Stand-by
portion of the XRAM (16Kbyte).
It can range from 4.5 to 5.5V (6V for a reduced amount of time during the device
life, 4.0V when RTC and 32 kHz on-chip oscillator amplifier are turned off). In
running mode, this pin can be tied low during reset without affecting 32 kHz
oscillator, RTC and XRAM activities, since the presence of a stable V
guarantees the proper biasing of all those modules.
Two 8-bit bidirectional I/O ports P0L and P0H, bit-wise programmable for input or
output via direction bit. Programming an I/O pin as input forces the corresponding
output driver to high impedance state. The input threshold of Port 0 is selectable
(TTL or CMOS).
In case of an external bus configuration, PORT0 serves as the address (A) and
as the address / data (AD) bus in multiplexed bus modes and as the data (D) bus
in demultiplexed bus modes.
Demultiplexed bus modes
Multiplexed bus modes
Data path width
P0L.0 – P0L.7:
P0H.0 – P0H.7:
Data path width
P0L.0 – P0L.7:
P0H.0 – P0H.7:
Doc ID 11917 Rev 3
8-bit
D0 – D7
I/O
8-bit
AD0 – AD7
A
8 – A15
Function
16-bi
D0 - D7
D8 - D15
16-bi
AD0 - AD7
A
D8 - AD15
DD
turned off) to bias the 32
ST10F272B/ST10F272E
DD