D12320VF25V Datasheet, PDF (488/1146 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 12 Serial Communication Interface (SCI)
The BRR setting is found from the following formulas.
Asynchronous mode:
N=
φ
× 10⁶ – 1
64 × 2^2n–1 × B
Synchronous mode:
N=
φ
× 10⁶ – 1
8 × 2^2n–1 × B
Where B: Bit rate (bits/s)
N: BRR setting for baud rate generator (0 ≤ N ≤ 255)
φ: Operating frequency (MHz)
n: Baud rate generator input clock (n = 0 to 3)
(See the table below for the relation between n and the clock.)
SMR Setting
n
Clock
CKS1
CKS0
0
φ
0
0
1
φ/4
0
1
2
φ/16
1
0
3
φ/64
1
1
The bit rate error in asynchronous mode is found from the following formula:
φ × 10⁶
Error (%) = {
– 1} × 100
(N + 1) × B × 64 × 2^2n–1
Rev.7.00 Feb. 14, 2007 page 454 of 1108
REJ09B0089-0700