Clock Synchronous Serial I/O Mode - von Gunthard Kraus

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R8C/10, R8C/11, R8C/12, R8C/13 Group Serial I/O Operation (Clock Synchronous Serial I/O Mode) 3.5ms 250µs 250µs 1ms CLK0 1 2 3 4 10 1 TXD0 1 2 3 4 10 1 RXD0 1 2 3 4 10 1 8µs CLK0 TxD0 D0 D1 D2 D3 D4 D5 D6 D7 RxD0 D0 D1 D2 D3 D4 D5 D6 D7 Figure 1. Transmit Format 3.1 Pins Used Table 1. List of Pins Used and Their Functions Pin name I/O Function P14/TxD0 Output Serial data output P15/RxD0 Input Serial data input P16/CLK0 Output Transfer clock output 3.2 Memory Usage Table 2. Memory Usage Memory Usage Size Remarks ROM 167 bytes In only the main.c module RAM 21 bytes In only the main.c module Maximum user stack used 6 bytes sfr_init function: 3 bytes Cs_sral function: 3 bytes Maximum interrupt stack used 0 byte Unused The size of the used memory differs with the C compiler version and compile options. The above applies to the conditions given below. • C compiler: M3T-NC30WA V.5.20 Release 1 • Compile option: -g -O -finfo Note - R8C Note: Unusable in the R8C/Tiny-only free version. Table 4. RAM Usage and Definition Symbol Type Size Content serial_cnt unsigned char 1 byte Transmit/receive data counter rcv_buf[10] unsigned char 10 bytes Receive buffer trn_buf[10] unsigned char 10 bytes Transmit buffer REJ05B0452-0110Z/Rev.1.10 August 2004 Page 2 of 11
R8C/10, R8C/11, R8C/12, R8C/13 Group Serial I/O Operation (Clock Synchronous Serial I/O Mode) 4. Flow Chart 4.1 Initial Operation and Main Loop main asm("FCLR I") prc0 = 1 cm13 = 1 cm15 = 1 cm05 = 0 cm16 = 0 cm17 = 0 cm06 = 0 ; Interrupt disabled ; System clock control register protect cancellation ; XIN-XOUT pin ; XIN-XOUT drive capability : HIGH ; Main clock : oscillation ; No division mode ; Main clock division CM16, CM17 enabled asm("nop") asm("nop") asm("nop") ; Wait for stability (Main clock) asm("nop") ocd2 = 0 prc0 = 0 SFR INITIAL SETTING sfr_init ; Select main clock ; System clock control register protect ; SFR initial setting (port initial setting, timer setting) Main period process No ; Timer X wait for request (250µs) Yes ir_txic = 0 ; Timer X request flag clear SERIAL TRANSMIT/RECEIVE Cs_sral ; Serial transmit/receive process (clock synchronized) REJ05B0452-0110Z/Rev.1.10 August 2004 Page 3 of 11
Page 1: APPLICATION NOTE R8C/10, R8C/11, R8
Page 5 and 6: R8C/10, R8C/11, R8C/12, R8C/13 Grou
Page 11: R8C/10, R8C/11, R8C/12, R8C/13 Grou

Clock Synchronous Serial I/O Mode - von Gunthard Kraus

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