
Rev. 1.20
136
November 20, 2019
Rev. 1.20
137
November 20, 2019
HT66F2740
12V High Current Flash MCU
HT66F2740
12V High Current Flash MCU
Start
SCL
SDA
SCL
SDA
1
0
ACK
Slave Address
SRW
Stop
1
1
0
1
0
1
0
1
0
0
1
0
1
0
0
I
2
C time-out
counter start
I
2
C time-out counter reset
on SCL negative transition
I
2
C Time-out
When an I
2
C time-out counter overflow occurs, the counter will stop and the SIMTOEN bit will
be cleared to zero and the SIMTOF bit will be set high to indicate that a time-out condition has
occurred. The time-out condition will also generate an interrupt which uses the USIM interrupt
vector. When an I
2
C time-out occurs, the I
2
C internal circuitry will be reset and the registers will be
reset into the following condition:
Registers
After I
2
C Time-out
SIMD, SIMA, SIMC0
No change
SIMC1
Reset to POR condition
I
2
C Registers after Time-out
The SIMTOF flag can be cleared by the application program. There are 64 time-out periods which
can be selected using SIMTOS bit field in the SIMTOC register. The time-out time is given by the
formula: ((1~64)×32)/f
SUB
. This gives a time-out period which ranges from about 1ms to 64ms.
• SIMTOC Register
Bit
7
6
5
4
3
2
1
0
Name
SIMTOEN SIMTOF SIMTOS5 SIMTOS4 SIMTOS3 SIMTOS2 SIMTOS1 SIMTOS0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7
SIMTOEN
: USIM I
2
C Time-out control
0: Disable
1: Enable
Bit 6
SIMTOF
: USIM I
2
C Time-out flag
0: No time-out occurred
1: Time-out occurred
This bit is set high when time-out occurs and can only be cleared by application
program.
Bit 5~0
SIMTOS5~SIMTOS0
: USIM I
2
C Time-out period selection
I
2
C time-out clock source is f
SUB
/32.
I
2
C time-out time is equal to (SIMTOS[5:0]+1)×(32/f
SUB
).