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RL78/G1A CHAPTER 12 SERIAL ARRAY UNIT
R01UH0305EJ0200 Rev.2.00 412
Jul 04, 2013
12.3.3 Serial mode register mn (SMRmn)
The SMRmn register is a register that sets an operation mode of channel n. It is also used to select an operation clock
(f
MCK), specify whether the serial clock (fSCK) may be input or not, set a start trigger, an operation mode (CSI, UART, or
simplified I
2
C), and an interrupt source. This register is also used to invert the level of the receive data only in the UART
mode.
Rewriting the SMRmn register is prohibited when the register is in operation (when SEmn = 1). However, the MDmn0
bit can be rewritten during operation.
The SMRmn register can be set by a 16-bit memory manipulation instruction.
Reset signal generation sets the SMRmn register to 0020H.
Figure 12-6. Format of Serial Mode Register mn (SMRmn) (1/2)
Address: F0110H, F0111H (SMR00) to F0116H, F0117H (SMR03), After reset: 0020H R/W
F0150H, F0151H (SMR10), F0152H, F0153H (SMR11)
Note 1
Symbol 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
SMRmn
CKS
mn
CCS
mn
0 0 0 0 0
STS
mn
Note 2
0
SIS
mn0
Note 2
1 0 0
MD
mn2
MD
mn1
MD
mn0
CKS
mn
Selection of operation clock (f
MCK) of channel n
0 Operation clock CKm0 set by the SPSm register
1 Operation clock CKm1 set by the SPSm register
Operation clock (fMCK) is used by the edge detector. In addition, depending on the setting of the CCSmn bit and the
higher 7 bits of the SDRmn register, a transfer clock (f
TCLK) is generated.
CCS
mn
Selection of transfer clock (f
TCLK) of channel n
0 Divided operation clock fMCK specified by the CKSmn bit
1 Clock input fSCK from the SCKp pin (slave transfer in CSI mode)
Transfer clock fTCLK is used for the shift register, communication controller, output controller, interrupt controller, and
error controller. When CCSmn = 0, the division ratio of operation clock (f
MCK) is set by the higher 7 bits of the
SDRmn register.
STS
mn
Note 2
Selection of start trigger source
0 Only software trigger is valid (selected for CSI, UART transmission, and simplified I
2
C).
1 Valid edge of the RXDq pin (selected for UART reception)
Transfer is started when the above source is satisfied after 1 is set to the SSm register.
Notes 1. SMR00 to SMR03: All products
SMR10, SMR11: 32, 48, and 64-pin products
2. The SMR01, SMR03, and SMR11 registers only.
Caution Be sure to clear bits 13 to 9, 7, 4, and 3 (or bits 13 to 6, 4, and 3 for the SMR00, SMR02, or SMR10
register) to “0”. Be sure to set bit 5 to “1”.
Remark m: Unit number (m = 0, 1), n: Channel number (n = 0 to 3), p: CSI number (p = 00, 01, 10, 11, 20, 21),
q: UART number (q = 0 to 2), r: IIC number (r = 00, 01, 10, 11, 20, 21)
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