
Rev. 1.20
134
November 20, 2019
Rev. 1.20
135
November 20, 2019
HT66F2740
12V High Current Flash MCU
HT66F2740
12V High Current Flash MCU
Start
SIMTOF=1?
SET SIMTOEN
CLR SIMTOF
RETI
HAAS=1?
HTX=1?
SRW=1?
Read from SIMD to
release SCL Line
RETI
RXAK=1?
Write data to SIMD to
release SCL Line
CLR HTX
CLR TXAK
Dummy read from SIMD
to release SCL Line
RETI
RETI
SET HTX
Write data to SIMD to
release SCL Line
RETI
CLR HTX
CLR TXAK
Dummy read from SIMD
to release SCL Line
RETI
Yes
No
No
Yes
Yes
No
Yes
No
No
Yes
I
2
C Bus ISR Flow Chart
I
2
C Time-out Control
In order to reduce the problem of I
2
C lockup due to reception of erroneous clock sources, a time-out
function is provided. If the clock source to the I
2
C is not received for a while, then the I
2
C circuitry
and registers will be reset after a certain time-out period. The time-out counter starts counting on an
I
2
C bus “START” & “address match” condition, and is cleared by an SCL falling edge. Before the
next SCL falling edge arrives, if the time elapsed is greater than the time-out setup by the SIMTOC
register, then a time-out condition will occur. The time-out function will stop when an I
2
C “STOP”
condition occurs.