15-44
MSM66591/ML66592 User's Manual
Chapter 15 Serial Port Functions
[3]
SCI3 Transmit/Receive Buffer Register (S3BUF0)
S3BUF0 is an 8-bit register that holds transmit/receive data during a serial port trans-
mit/receive operation. S3BUF0 has a double structure, in which the contents are
different in read/write. If in read, S3BUF0 functions as a receive buffer, and if in write,
S3BUF0 functions as a transmit buffer.
When a receive operation ends, the content of the receive register is transferred to the
S3BUF0 receive buffer, and a receive interrupt request is generated at the same time.
The content of the S3BUF0 receive buffer is held until the next receive operation ends.
When receive mode is in UART multiprocessor communication mode, and if receive
data is ignored, the content of S3BUF0 is not updated even at completion of the receive
operation, and a receive interrupt request is not generated.
At reset (when the
RES
signal is input, the BRK instruction is executed, the watchdog
timer is overflown, or an operation code trap is generated), S3BUF0 becomes unde-
fined.
[4]
SCI3 Receive Buffer Registers (S3BUF1, S3BUF2, S3BUF3)
S3BUF1, S3BUF2, and S3BUF3 are 8-bit registers that store valid received data when
the SR3EXP bit of SR3CON is set to "1" (4-stage buffer mode).
These registers are read-only and cannot be written to. During the 4-stage buffer mode,
at the completion of each 1-byte reception, the contents of the receive register is
transferred to a receive buffer register in the order of S3BUF0, S3BUF1, S3BUF2,
S3BUF3, S3BUF0, etc. At the same time, a receive interrupt request is generated.
(Ring Buffer Type)
When the receive mode is the UART multiprocessor communication mode and the
received data is ignored, even after completion of a receive operation, the contents of
S3BUF1, S3BUF2, and S3BUF3 will not be updated and a receive interrupt request will
not be generated.
At reset (when the
RES
signal is input, the BRK instruction is executed, the watchdog
timer is overflown, or an operation code trap is generated), the contents of S3BUF1,
S3BUF2, and S3BUF3 are undefined.
[5]
SCI3 Transmit and Receive Registers
The SCI3 transmit and receive registers are two 8-bit shift registers that actually per-
form shift operations during a transmit/receive operation.
The transmit and receive registers and the transmit/receive buffer registers have a
double structure. If a receive operation ends, the data received by the receive register
is transferred to S3BUF, and a receive interrupt request is generated.
The transmit and receive registers cannot be read/written by the program.
Summary of Contents for MSM66591
Page 15: ...Contents 12...
Page 17: ......
Page 18: ...Overview Chapter 1 1...
Page 19: ......
Page 30: ...Description of Pins Chapter 2 2...
Page 31: ......
Page 44: ...CPU Architecture Chapter 3 3...
Page 45: ......
Page 101: ...3 56 MSM66591 ML66592User sManual Chapter 3 CPU Architecture...
Page 102: ...CPU Control Functions Chapter 4 4...
Page 103: ......
Page 111: ...4 8 MSM66591 ML66592User sManual Chapter 4 CPU Control Functions...
Page 112: ...Memory Control Functions Chapter 5 5...
Page 113: ......
Page 117: ...5 4 MSM66591 ML66592User sManual Chapter 5 Memory Control Functions...
Page 118: ...Port Functions Chapter 6 6...
Page 119: ......
Page 152: ...Output Pin Control Pin OE Chapter 7 7...
Page 153: ......
Page 155: ...7 2 MSM66591 ML66592User sManual Chapter 7 Output Pin Control Pin OE...
Page 156: ...Clock Generation Circuit Chapter 8 8...
Page 157: ......
Page 160: ...Time Base Counter TBC Chapter 9 9...
Page 161: ......
Page 164: ...Watchdog Timer WDT Chapter 10 10...
Page 165: ......
Page 170: ...Flexible Timer FTM Chapter 11 11 11...
Page 171: ......
Page 213: ...11 42 MSM66591 ML66592User sManual Chapter 11 Flexible Timer FTM...
Page 214: ...General Purpose 8 Bit Timer Function Chapter 12 12...
Page 215: ......
Page 223: ...12 8 MSM66591 ML66592User sManual Chapter 12 General Purpose 8 Bit Timer Function...
Page 224: ...PWM Functions Chapter 13 13...
Page 225: ......
Page 244: ...Baud Rate Generator Functions Chapter 14 14...
Page 245: ......
Page 263: ...14 18 MSM66591 ML66592User sManual Chapter 14 Baud Rate Generator Functions...
Page 264: ...Serial Port Functions Chapter 15 15...
Page 265: ......
Page 348: ...A D Converter Functions Chapter 16 16...
Page 349: ......
Page 381: ...16 32 MSM66591 ML66592User sManual Chapter 16 A D Converter Functions...
Page 382: ...Transition Detector Functions Chapter 17 17...
Page 383: ......
Page 387: ...17 4 MSM66591 ML66592User sManual Chapter 17 Transition Detector Functions...
Page 388: ...Peripheral Functions Chapter 18 18...
Page 389: ......
Page 392: ...External Interrupt Request Function Chapter 19 19...
Page 393: ......
Page 396: ...Interrupt Request Processing Function Chapter 20 20...
Page 397: ......
Page 407: ...20 10 MSM66591 ML66592User sManual Chapter 20 Interrupt Request Processing Function...
Page 408: ...Bus Port Functions Chapter 21 21...
Page 409: ......
Page 413: ...21 4 MSM66591 ML66592User sManual Chapter 21 Bus Port Functions...
Page 414: ...Expansion Port Chapter 22 22...
Page 415: ......
Page 420: ...Serial Port with FIFO SCI5 Chapter 23 23...
Page 421: ......
Page 431: ...23 10 MSM66591 ML66592User sManual Chapter 23 Serial Port with FIFO SCI5...
Page 432: ...RAM Monitor Function Chapter 24 24...
Page 433: ......
Page 441: ...24 8 MSM66591 ML66592User sManual Chapter 24 RAM Monitor Function...
Page 442: ...25 Electrical Characteristics Chapter 25...
Page 443: ......
Page 458: ...Package Dimensions Chapter 26 26...
Page 459: ......
Page 461: ...26 2 MSM66591 ML66592User sManual Chapter 26 Package Dimensions...
Page 462: ...Revision History Chapter 27 27...
Page 463: ......
Page 465: ...27 2 MSM66591 ML66592User sManual Chapter 27 Revision History...