H8SSLASH2224 datasheet(692/1071 Pages) RENESAS

692 / 1071 page

Section 15 Serial Communication Interface (SCI)

Rev. 5.00 Aug 08, 2006 page 606 of 982

REJ09B0054-0500

15.6.4

Serial Data Reception (Clocked Synchronous Mode)

Figure 15.21 shows an example of SCI operation for reception in clocked synchronous mode. In

serial reception, the SCI operates as described below.

1. The SCI performs internal initialization synchronous with a synchronous clock input or output,

starts receiving data, and stores the received data in RSR.

2. If an overrun error occurs (when reception of the next data is completed while the RDRF flag

in SSR is still set to 1), the ORER bit in SSR is set to 1. If the RIE bit in SCR is set to 1 at this

time, an ERI interrupt request is generated, receive data is not transferred to RDR, and the

RDRF flag remains to be set to 1.

3. If reception is completed successfully, the RDRF bit in SSR is set to 1, and receive data is

transferred to RDR. If the RIE bit in SCR is set to 1 at this time, an RXI interrupt request is

generated. Continuous reception is possible because the RXI interrupt routine reads the

receive data transferred to RDR before reception of the next receive data has finished.

Bit 7

Serial data

Synchronization

clock

1 frame

RDRF

ORER

ERI interrupt request

generated by overrun

error

RXI interrupt

request generated

RDR data read and

RDRF flag cleared

to 0 in RXI interrupt

RXI interrupt

request

generated

Bit 0

Bit 7

Bit 0

Bit 1

Bit 6

Bit 7

Figure 15.21 Example of SCI Operation in Reception

Reception cannot be resumed while a receive error flag is set to 1. Accordingly, clear the ORER,

FER, PER, and RDRF bits to 0 before resuming reception. Figure 15.22 shows a sample flow

chart for serial data reception.

An overrun error occurs or synchronous clocks are output until the RE bit is cleared to 0 when an

internal clock is selected and only receive operation is possible. When a transmission and

reception will be carried out in a unit of one frame, be sure to carry out a dummy transmission

with only one frame by the simultaneous transmit and receive operations at the same time.

H8S/2224 Scheda tecnica(PDF) 692 Page - Renesas Technology Corp

H8S/2224 Scheda tecnica(HTML) 692 Page - Renesas Technology Corp

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Scheda tecnica Scarica

Link URL