Automatic Low-Hold Function For Scl; Function To Prevent Wrong Transmission Of Transmit Data - Renesas RX100 Series User Manual

RX13T Group
24.8

Automatic Low-Hold Function for SCL

24.8.1

Function to Prevent Wrong Transmission of Transmit Data

If the shift register (ICDRS) is empty when data have not been written to the I
the RIIC in transmission mode (ICCR2.TRS bit is 1), the SCL0 line is automatically held at the low level over the
intervals shown below. This low-hold period is extended until data for transmission have been written, which prevents
the unintended transmission of erroneous data.
Master transmit mode
 Low-level interval after a start condition or restart condition is issued
 Low-level interval between the ninth clock cycle of one transfer and the first clock cycle of the next
Slave transmit mode
 Low-level interval between the ninth clock cycle of one transfer and the first clock cycle of the next
[Master transmit mode]
Automatic low-hold (to prevent wrong transmission)
S 1
SCL0
SDA0
BBSY
Transmit data (7-bit address + W)
AASy
TRS
TDRE
RDRF
Write data to ICDRT register
(7-bit address + W)
[Slave transmit mode]
S 1 2
SCL0
7-bit slave address
SDA0
BBSY
AASy
TRS
TDRE
RDRF
Figure 24.30 Automatic Low-Hold Operation in Transmit Mode
R01UH0822EJ0100 Rev.1.00
Jul 31, 2019
2 3 4 5 6 7 8
7-bit slave address
W
3 4 5 6 7 8 9
R ACK
Address match
Write data to ICDRT register
2
Automatic low-hold (to prevent wrong transmission)
9 1 2 3 4
Data (DATA 1)
ACK
Transmit data (DATA 1)
Write data to ICDRT register
(DATA 1)
Automatic low-hold (to prevent wrong transmission)
1 2 3 4 5
Data (DATA 1)
Transmit data (DATA 1)
(DATA 1)
2
24. I C-bus Interface (RIICa)
C-bus transmit data register (ICDRT) with
5 6 7 8 9
ACK
Transmit data (DATA 2)
Write data to ICDRT register
(DATA 2)
Automatic low-hold
(to prevent wrong
transmission)
6 7 8 9 1
ACK
Transmit data (DATA 2)
Write data to ICDRT register
(DATA 2)
Page 781 of 1041
Automatic low-hold
(to prevent wrong
transmission)
1 2
2 3