Short-Circuit Protection Function - Holtek BS86DH12C Manual

VDD
Reference
VCC2
VCC1
VDD VCC1
Level
CWSEL1
Shift
R11=12kΩ
R12=3kΩ
Note: The CWSEL1 and CWSEL2 are generated by the internal A/D converter input channel selection. When the
A/D converter selects the V
rise CWSEL1=1 or CWSEL2=1.

Short-circuit Protection Function

All high voltage I/O pins share the same short-circuit protection circuit which contains a 2-bit clock
counter. The counter, with an initial value of 0, has a clock source derived from f
which is selected by the SFRTC bit in the PWRDET register.
The high voltage I/O short-circuit protection circuit compares the output signal PDn_DOUT with the
input signal, PDn_DIN. If the PDn_DOUT has the same value as the PDn_DIN, it indicates the high
voltage I/O is in a normal condition, and then the clock counter will be cleared. If the comparison
result of any high voltage I/O pins is different, the common clock counter will not be cleared.
When the comparison result is different and the count value of the clock counter is more than 2~3,
the short-circuit protection circuit will determine it as a short-circuit condition. After the short-
circuit condition occurs, the high voltage short circuit interrupt flag, HVSCF, will be set high.
The short-circuit protection circuits use the same interrupt vector for all high voltage I/O pins. When
a short-circuit situation occurs on any one of the high voltage I/O pins, a high voltage short circuit
interrupt will be triggered. When this condition appears, if the global interrupt enable bit and its
corresponding interrupt control bit are enabled and the stack is not full, a subroutine call to the high
voltage short circuit interrupt vector will take place.
However, it must be noted that the short-circuit protection function is only available when the
voltage detector detects the condition of PWRRDYF=1.
Rev. 1.00
High Voltage Touch A/D Flash MCU with HVIO
V
DD
Voltage Detector
DP
V
CC2
Voltage Detector
CWSEL2
V
CC1O
(To A/D Converter)
HVSS
or V signal as its internal input, then CWSEL1=0 or CWSEL2=0, othe-
CC1O CC2O
Voltage Detector Circuit
76
BS86DH12C
VCC2 VDD
Level
Shift
VDD VCC2
Level
Shift
R21=12kΩ
V
CC2O
(To A/D Converter)
R22=3kΩ
HVSS
/32 or f
LIRC
October 26, 2018
PWRRDY
PWRRDYF
/16,
LIRC