M16C80 Datasheet, PDF (175/358 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/80 SERIES

M16C/80 Group
20. UARTi Special Mode Register (i = 2 to 4)
Clock Phase Setting
With bit 1 of UARTi special mode register 3 (addresses 032516 and 02F516 [i = 3 or 4]) and bit 6 of
UARTi transmission-reception control register 0 (addresses 032C16 and 02FC16 [i = 3 or 4]), four
combinations of transfer clock phase and polarity can be selected.
Bit 6 of UARTi transmission-reception control register 0 (addresses 032C16 and 02FC16 [i = 3 or 4])
sets transfer clock polarity, whereas bit 1 of UARTi special mode register 3 (addresses 032516 and
02F516 [i = 3 or 4]) sets transfer clock phase.
Transfer clock phase and polarity must be the same between the master and slave involved in the
transfer.
< Master (Internal Clock) (DINC = 0) >
Figure 20.7 shows the transmission and reception timing.
< Slave (External Clock) (DINC = 1) >
• With “0” for bit 1 (CKPH) of UARTi special mode register 3 (addresses 032516 and 02F516 [i = 3 or
4]), when an SSi input pin is H level, output data is high impedance. When an SSi input pin is L level,
the serial transmission start condition is satisfied, though output is indeterminate. After that, serial
transmission is synchronized with the clock. Figure 20.8 shows the timing.
• With “1” for bit 1 (CKPH) of UARTi special mode register 3 (addresses 032516 and 02F516 [i = 3 or
4]), when an SSi input pin is H level, output data is high impedance. When an SSi input pin is L level,
the first data is output. After that, serial transmission is synchronized with the clock. Figure 20.9
shows the timing.
"H"
Master SS input
"L"
Clock output
"H"
(CKPOL=0, CKPH=0) ^"L"
Clock output
"H"
(CKPOL=1, CKPH=0) _"L"
Clock output
"H"
(CKPOL=0, CKPH=1) _"L"
Clock output
"H"
(CKPOL=1, CKPH=1) "L"
Data output timing ^"H"
"L"
Data input timing
D0
D1
D2
D3
D4
D5
D6
D7
Figure 20.7 The transmission and reception timing in master mode (internal clock)
Rev.1.00 Aug. 02, 2005 ^{Page 164} of 329
REJ09B0187-0100