RL78/F13, F14 CHAPTER 15 SERIAL ARRAY UNIT
R01UH0368EJ0210 Rev.2.10 891
Dec 10, 2015
15.5.7 Calculating transfer clock frequency
The transfer clock frequency for 3-wire serial I/O (CSI00, CSI01, CSI10, CSI11) communication can be calculated by the
following expressions.
(1) Master
(Transfer clock frequency) = {Operation clock (fMCK) frequency of target channel} ÷ (SDRmn[15:9] + 1) ÷ 2 [Hz]
(2) Slave
(Transfer clock frequency) = {Frequency of serial clock (fSCK) supplied by master}
Note
[Hz]
Note The permissible maximum transfer clock frequency is fMCK/6.
Remark The value of SDRmn[15:9] is the value of bits 15 to 9 of serial data register mn (SDRmn) (0000000B to
1111111B) and therefore is 0 to 127.
The operation clock (f
MCK) is determined by serial clock select register m (SPSm) and bit 15 (CKSmn) of serial mode
register mn (SMRmn).