Section 15 Serial Communication Interface (SCI)
Rev. 1.00 Apr. 28, 2008 Page 462 of 994
REJ09B0452-0100
15.9 Usage
Notes
15.9.1 Module
Stop Mode Setting
SCI operation can be disabled or enabled using the module stop control register. The initial setting
is for SCI operation to be halted. Register access is enabled by clearing module stop mode. For
details, see section 26, Power-Down Modes.
15.9.2
Break Detection and Processing
When framing error detection is performed, a break can be detected by reading the RxD pin value
directly. In a break, the input from the RxD pin becomes all 0s, and so the FER flag in SSR is set,
and the PER flag may also be set. Note that, since the SCI continues the receive operation even
after receiving a break, even if the FER flag is cleared to 0, it will be set to 1 again.
15.9.3
Mark State and Break Sending
When the TE bit in SCR is 0, the TxD pin is used as an I/O port whose direction (input or output)
and level are determined by DR and DDR of the port. This can be used to set the TxD pin to mark
state (high level) or send a break during serial data transmission. To maintain the communication
line at mark state until TE is set to 1, set both DDR and DR to 1. Since the TE bit is cleared to 0 at
this point, the TxD pin becomes an I/O port, and 1 is output from the TxD pin. To send a break
during serial transmission, first set DDR to 1 and DR to 0, and then clear the TE bit to 0. When the
TE bit is cleared to 0, the transmitter is initialized regardless of the current transmission state, the
TxD pin becomes an I/O port, and 0 is output from the TxD pin.
15.9.4
Receive Error Flags and Transmit Operations (Clocked Synchronous Mode Only)
Transmission cannot be started when a receive error flag (ORER, FER, or RER) is SSR is set to 1,
even if the TDRE flag in SSR is cleared to 0. Be sure to clear the receive error flags to 0 before
starting transmission. Note also that the receive error flags cannot be cleared to 0 even if the RE
bit in SCR is cleared to 0.
15.9.5
Relation between Writing to TDR and TDRE Flag
Data can be written to TDR irrespective of the TDRE flag status in SSR. However, if the new data
is written to TDR when the TDRE flag is 0, that is, when the previous data has not been
transferred to TSR yet, the previous data in TDR is lost. Be sure to write transmit data to TDR
after verifying that the TDRE flag is set to 1.
Содержание H8S/2100 Series
Страница 2: ...Rev 1 00 Apr 28 2008 Page ii of xxvi...
Страница 54: ...Section 1 Overview Rev 1 00 Apr 28 2008 Page 28 of 994 REJ09B0452 0100...
Страница 92: ...Section 2 CPU Rev 1 00 Apr 28 2008 Page 66 of 994 REJ09B0452 0100...
Страница 158: ...Section 5 Interrupt Controller Rev 1 00 Apr 28 2008 Page 132 of 994 REJ09B0452 0100...
Страница 244: ...Section 8 8 Bit PWM Timer PWMU Rev 1 00 Apr 28 2008 Page 218 of 994 REJ09B0452 0100...
Страница 330: ...Section 10 16 Bit Timer Pulse Unit TPU Rev 1 00 Apr 28 2008 Page 304 of 994 REJ09B0452 0100...
Страница 354: ...Section 11 16 Bit Cycle Measurement Timer TCM Rev 1 00 Apr 28 2008 Page 328 of 994 REJ09B0452 0100...
Страница 380: ...Section 12 16 Bit Duty Period Measurement Timer TDP Rev 1 00 Apr 28 2008 Page 354 of 994 REJ09B0452 0100...
Страница 416: ...Section 13 8 Bit Timer TMR Rev 1 00 Apr 28 2008 Page 390 of 994 REJ09B0452 0100...
Страница 494: ...Section 15 Serial Communication Interface SCI Rev 1 00 Apr 28 2008 Page 468 of 994 REJ09B0452 0100...
Страница 612: ...Section 18 I 2 C Bus Interface IIC Rev 1 00 Apr 28 2008 Page 586 of 994 REJ09B0452 0100...
Страница 706: ...Section 20 LPC Interface LPC Rev 1 00 Apr 28 2008 Page 680 of 994 REJ09B0452 0100...
Страница 752: ...Section 21 FSI Interface Rev 1 00 Apr 28 2008 Page 726 of 994 REJ09B0452 0100...
Страница 774: ...Section 23 RAM Rev 1 00 Apr 28 2008 Page 748 of 994 REJ09B0452 0100...
Страница 1008: ...Section 28 Electrical Characteristics Rev 1 00 Apr 28 2008 Page 982 of 994 REJ09B0452 0100...
Страница 1020: ...Rev 1 00 Apr 28 2008 Page 994 of 994 REJ09B0452 0100...
Страница 1023: ......
Страница 1024: ...H8S 2117R Group Hardware Manual...