M16C1N Datasheet, PDF (126/238 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/10 SERIES

M16C/1N Group
13. Serial I/O
UARTi transmit/receive mode registers
b7 b6 b5 b4 b3 b2 b1 b0
0
001
Symbol
UiMR (i=0,1)
Address
00A016, 00A816
When reset
0016
Bit symbol
Bit name
Function
RW
SMD0
SMD1
Serial I/O mode select bit
b2 b1 b0
0 0 1 : Clock synchronous serial
RW
I/O mode
RW
SMD2
RW
CKDIR
Internal/external clock
select bit
0 : Internal clock
1 : External clock (Note 1)
RW
STPS Invalid in clock synchronous serial I/O mode
RW
PRY
RW
PRYE
RW
Reserved bit
Set to "0"
RW
Note 1: Set the corresponding port direction register to "0".
Figure 13.6 UARTi transmit/receive mode register in clock synchronous serial I/O mode
Table 13.2 lists the functions of the input/output pins during clock synchronous serial I/O mode. This table
shows the pin functions when the transfer clock output from multiple pins is not selected. Note that for a
period from when the UARTi operation mode is selected to when transfer starts, the TxDi pin outputs an
"H". (If the N-channel open-drain is selected, this pin is in floating state.)
Table 13.2 Input/output pin functions in clock synchronous serial I/O mode
Function
Pin name
Method of selection
Remarks
Serial data output TxD0 (P14)
Port P14 cannot be used as an I/O port even when
performing only serial data input but not serial data output.
TxD1 (P37)
RxD1 input pin select bit
(bit 6 at address 00B016)="1"
Port P37 cannot be used as an I/O port even when
performing only serial data input but not serial data output.
Serial data input RxD0 (P15)
Port P15 direction register
(bit 5 at address 00E316)="0"
Port P15 can be used as an I/O port when performing only
serial data output but not serial data input.
RxD1 (P35)
Port P35 direction register
(bit 5 at address 00E716)="0"
RxD1 input pin select bit
(bit 6 at address 00B016)="1"
Port P35 can be used as an I/O port when performing only
serial data output but not serial data input.
RxD1 (P37)
Port P37 direction register
(bit 7 at address 00E716)="0"
RxD1 input pin select bit
(bit 6 at address 00B016)="0"
When setting Port P37 as RxD1, serial data output cannot
be performed.
Port P35 can be used as an I/O port.
Transfer clock output CLKi (P16, P36) Internal/external clock select bit
(bit 3 at addresses 00A016 and
00A816)="0"
Transfer clock input
CLKi (P16, P36)
Internal/external clock select bit
(bit 3 at address 00A016 and
00A816)="1"
Ports P16 and P36 direction
register (bit 6 at address 00E316
and 00E716)="0"
Rev.1.00 Oct 20, 2004 page 114 of 222
REJ09B0007-0100Z