Datasheet

Section 15 Serial Communication Interface (SCI, IrDA)
R01UH0309EJ0500 Rev. 5.00 Page 893 of 1408
Sep 24, 2012
H8S/2456, H8S/2456R, H8S/2454 Group
Bit Bit Name Initial Value R/W Description
2
1
0
ACS2
ACS1
ACS0
0
0
0
R/W
R/W
R/W
Asynchronous clock source selection (valid when
CKE1 = 1 in asynchronous mode)
Selects the clock source for the average transfer
rate.
The basic clock can be automatically set by
selecting the average transfer rate in spite of the
value of ABCS.
000: External clock input
001: Selects 115.152 kbps which is the average
transfer rate dedicated for φ= 10.667 MHz.
(Operates on a basic clock with a frequency
of 16 times the transfer rate.)
010: Selects 460.606 kbps which is the average
transfer rate dedicated for φ= 10.667 MHz.
(Operates on a basic clock with a frequency
of 8 times the transfer rate.)
011: Selects 720 kbps which is the average
transfer rate dedicated for φ = 32 MHz.
(Operates on a basic clock with a frequency
of 16 times the transfer rate.)
100: Reserved
101: Selects 115.196 kbps which is the average
transfer rate dedicated for φ = 16 MHz
(Operates on a basic clock with a frequency
of 16 times the transfer rate.)
110: Selects 460.784 kbps which is the average
transfer rate dedicated for φ = 16 MHz
(Operates on a basic clock with a frequency
of 16 times the transfer rate.)
111: Selects 720 kbps which is the average
transfer rate dedicated for φ = 16 MHz
(Operates on a basic clock with a frequency
of 8 times the transfer rate.)
Note that the average transfer rate does not
correspond to the frequency other than 10.667,
16, or 32 MHz.