Clock Synchronous Serial I/O Mode - von Gunthard Kraus

R8C/10, R8C/11, R8C/12, R8C/13 Group
Serial I/O Operation (Clock Synchronous Serial I/O Mode)
/************************************************************************************
Name: sfr_init
Parameters: None
Returns: None
Description: Initial setting of SFR registers
************************************************************************************/
void sfr_init(void){
/* Setting port registers */
p1 = p1 | 0x50; /* TxD0, CLK0 port off */
/* Setting port direction registers */
pd1 = pd1 | 0x50; /* TxD0, CLK0 port direction = output */
pd1 = pd1 & 0xdf; /* RxD0 port direction = input */
txck0 = 1; /* Timer X count source = f8 */
txck1 = 0;
/* 16MHz* 1/8 * 50 * 10 = 250us */
prex = 50-1; /* Setting Prescaler X register */
tx = 10-1; /* Setting timer X register */
txmr = 0x00; /* Timer X : timer mode */
txs = 1; /* Timer X count start flag = start */
}
/* Clock synchronous serial I/O setting */
u0mr = 0x01; /* Set clock synchronous serial I/O mode */
/* Internal Clock */
u0c0 = 0x01; /* f8 is selected */
/* Data present in transmit register */
/* (during transmission) */
/* TXD0 pin is CMOS output */
/* Transmit data is output at falling edge of */
/* transfer clock and receive data */
/* is input at rising edge */
/* LSB first */
u0rrm = 0; /* Continuous receive mode disabled */
u0brg = 8-1; /* Set baud rate:1 clock 8us */
re_u0c1 = 1; /* Reception enabled */
REJ05B0452-0110Z/Rev.1.10 August 2004 Page 7 of 11