Special pins

AN2595 - Application note

14/20

There are two ways of disabling the BHE alternate function on P3.12:

–

–

Disable it via bit BYTDIS of the SYSCON register.

4

Special pins

4.1

External access enable/standby voltage supply pin

A low level applied to this pin during and after reset forces the ST10F27xZx to start the

program execution from the external memory space. A high level will start the program

execution from internal memory.

reference voltage for the low-power embedded voltage regulator which generates the

internal 1.8 V supply for the XRTC module (when not disabled) and to retain data inside the

Standby portion of the XRAM (16 Kbyte). It can range from 4.5 to 5.5 V.

4.2

RPD pin

The RPD pin (return from power-down) generates the proper internal timing sequence when

interruptible power-down mode is used.

If the interruptible power-down mode is not used, the RPD pin can be connected to the

ground (directly or via a resistor of 1 M

Ω (maximum). In this configuration, the device always

performs asynchronous resets.

5

Reset

For information on ST10F27x reset, please refer to the product user manual.