Datasheet

Table Of Contents
Section 13 Serial Communication Interface
Page 406 of 846 REJ09B0140-0900 Rev. 9.00
Sep 16, 2010
H8S/2215 Group
1 2 3 4 5 6 7 8 9 10111213141516171819 2021 2322 2425 1 2 5 6 7 8 9 101112131415 161718 1920212223242534
12 MHz
5.76 MHz
123
3 MHz
1.8421 MHz
4 5 6 7 8 9 10 11 12 13 14 15 16 17
1
18 19 20 21 2322 24 25 26
2 3 4 5 6 7 8 9 10 11 12 1413 15 16
27 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 1 228 29
123
12 MHz
7.3684 MHz
4 5 6 7 8 9 10 11 12 13 14 15 16 17
1
18 19 20 21 2322 24 25 26
2 3 4 5 6 7 8 9 10 11 12 1413 15 16
27 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 1 228 29
123
12 MHz
7.3684 MHz
4 5 6 7 8 9 10 11 12 13 14 15 16 17
1
18 19 20 21 2322 24 25 26
23 45 67 8
1 2345678
27 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 1 228 29
Base clock
24 MHz/2 = 12 MHz
12 MHz × (12/25)
= 5.76 MHz
(Average)
Base clock with 720-kbps average transfer rate (ACS3 to ACS0 = B'1010)
Average transfer rate = 5.76 MHz/8= 720 kbps
Average error with 720 kbps = ±0%
Base clock
24 MHz/2 = 12 MHz
12 MHz × (35/57)
= 7.3684 MHz
(Average)
Base clock with 921.053-kbps average transfer rate (ACS3 to ACS0 = B'1011)
Average transfer rate = 7.3684 MHz/8= 921.053 kbps
Average error with 921.1 kbps = -0.059%
Note: * The lengh of one bit varies according to the base clock synchronization.
Base clock
24 MHz/2 = 12 MHz
12 MHz × (35/57)
= 7.3684 MHz
(Average)
1 bit = base clock × 16*
1 bit = base clock × 8*
1 bit = base clock × 8*
Base clock with 460.526-kbps average transfer rate (ACS3 to ACS0 = B'1001)
Average transfer rate = 7.3684 MHz/16 = 460.526 kbps
Average error with 460.6kbps = -0.059%
1 bit = base clock × 16*
Base clock
24 MHz/8 = 3 MHz
3 MHz × (35/57)
= 1.8421 MHz
(Average)
When φ = 24 MHz
Base clock with 115.132-kbps average transfer rate (ACS3 to ACS0 = B'1000)
Average transfer rate =1.8421 MHz/16 = 115.132 kbps
Average error with 115.2 kbps = -0.0059%
Figure 13.4 Examples of Base Clock when Average Transfer Rate Is Selected (2)