Datasheet
RL78/L12    CHAPTER 12 SERIAL ARRAY UNIT 
R01UH0330EJ0200 Rev.2.00      389 
Dec 13, 2013 
12.3.2 Serial clock select register m (SPSm) 
The SPSm register is a 16-bit register that is used to select two types of operation clocks (CKm0, CKm1) that are 
commonly supplied to each channel. CKm1 is selected by bits 7 to 4 of the SPSm register , and CKm0 is selected by bits 
3 to 0. 
Rewriting the SPSm register is prohibited when the register is in operation (when SEmn = 1). 
The SPSm register can be set by a 16-bit memory manipulation instruction. 
The lower 8 bits of the SPSm register can be set with an 8-bit memory manipulation instruction with SPSmL. 
Reset signal generation clears the SPSm register to 0000H. 
Figure 12-4. Format of Serial Clock Select Register m (SPSm) 
Address: F0126H, F0127H After reset: 0000H R/W 
Symbol 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 
SPSm  0 0 0 0 0 0 0 0 
PRS
m13
PRS
m12
PRS
m11
PRS
m10
PRS
m03 
PRS
m02 
PRS
m01
PRS
m00
PRS
mk3 
PRS
mk2 
PRS
mk1
PRS
mk0 
Section of operation clock (CKmk)
 Note 1
 fCLK = 2 MHz fCLK = 5 MHz fCLK = 10 MHz fCLK = 20 MHz  fCLK = 24 MHz
0 0 0 0 fCLK  2 MHz  5 MHz  10 MHz  20 MHz  24 MHz 
0 0 0 1 fCLK/2  1 MHz  2.5 MHz  5 MHz  10 MHz  12 MHz 
0 0 1 0 fCLK/2
2
  500 kHz  1.25 MHz  2.5 MHz  5 MHz  6 MHz 
0 0 1 1 fCLK/2
3
  250 kHz  625 kHz  1.25 MHz  2.5 MHz  3 MHz 
0 1 0 0 fCLK/2
4
  125 kHz  313 kHz  625 kHz  1.25 MHz  1.5 MHz 
0 1 0 1 fCLK/2
5
  62.5 kHz  156 kHz  313 kHz  625 kHz  750 kHz 
0 1 1 0 fCLK/2
6
  31.3 kHz  78.1 kHz  156 kHz  313 kHz  375 kHz 
0 1 1 1 fCLK/2
7
  15.6 kHz  39.1 kHz  78.1 kHz  156 kHz  187.5 kHz 
1 0 0 0 fCLK/2
8
  7.81 kHz  19.5 kHz  39.1 kHz  78.1 kHz  93.8 kHz 
1 0 0 1 fCLK/2
9
  3.91 kHz  9.77 kHz  19.5 kHz  39.1 kHz  46.9 kHz 
1 0 1 0 fCLK/2
10
  1.95 kHz  4.88 kHz  9.77 kHz  19.5 kHz  23.4 kHz 
1 0 1 1 fCLK/2
11
  977 Hz  2.44 kHz  4.88 kHz  9.77 kHz  11.7 kHz 
1 1 0 0 fCLK/2
12
  488 Hz  1.22 kHz  2.44 kHz  4.88 kHz  5.86 kHz 
1 1 0 1 fCLK/2
13
  244 Hz  610 Hz  1.22 kHz  2.44 kHz  2.93 kHz 
1 1 1 0 fCLK/2
14
  122 Hz  305 Hz  610 Hz  1.22 kHz  1.46 kHz 
1 1 1 1 fCLK/2
15
  61 Hz  153 kHz  305 Hz  610 Hz  732 Hz 
Note  When changing the clock selected for fCLK (by changing the system clock control register (CKC) 
value), do so after having stopped (serial channel stop register m (STm) = 000FH) the operation of 
the serial array unit (SAU). 
Caution  Be sure to clear bits 15 to 8 to “0”. 
Remarks 1. f
CLK: CPU/peripheral hardware clock frequency 
 f
SUB: Subsystem clock frequency 
 2.  m: Unit number (m = 0) 
  3.  k = 0, 1 










