ML63611 User’s Manual
Chapter 12 Serial Port (SIO)
12 – 5
OPTION B (D): 1.5 V (3.0 V), With regulator
circuit for LCD bias
OPTION A (C): 1.5 V (3.0 V), Without regulator
circuit for LCD bias
(2) Send buffer registers (STBUFL, STBUFH)
STBUFL and STBUFH are 4-bit special function registers (SFRs) that set send data for serial port send
operation.
LSB/MSB selection (described later) allows the data send direction (LSB or MSB first) to be specified. Both
STBUFL and STBUFH are initialized to “0” at system reset.
Send operation begins when send data is set to STBUFH. Be sure to set send data to STBUFL before
setting data to STBUFH.
Also set the baud rate and send mode before beginning send operation.
If send operation is already under way when send data is set to STBUFH, send for the new data begins when
the prior send has ended, and at the same time an interrupt request signal (STINT) is generated. In the STINT
interrupt routine the program should first write the send data to STBUFL and STBUFH to assure no pauses
in the send sequence.
(3) Send register
The send register is a shift register that handles the shift operation in send. At system reset it is cleared to
00H. The send register cannot be directly accessed from the CPU.
The hardware send flow is indicated in Figure 12-2, to explain the timing for transfer of data from
STBUFL/H to the send register.
First set the send mode and baud rate. When send data is set to STBUFH, the status (SSTAT) buffer full flag
(BFULL) is set to “1”, and unless send operation is already under way the content of STBUFL/H is
transferred to the send register and send operation begins. When send operation begins the BFULL flag is
reset to “0”, and the next send data can be set to STBUFL/H.
If prior data send operation is not complete, the send data is held in STBUFL/H until send is completed. In
this case BFULL remains set to “1”. When the prior send operation is complete the send data will be
transferred from STBUFL/H to the send register, and send begins.
Note:
When BFULL is “1” it is possible to set data to STBUFL/H, but prior data set to STBUFL/H that is being held
there is overwritten and lost. Always set data after verifying that the BFULL flag is “0”.
TB3
TB2
TB1
TB0
STBUFL (0A4H)
(R/W)
bit 3
bit 2
bit 1
bit 0
TB7
TB6
TB5
TB4
STBUFH (0A5H)
(R/W)
bit 3
bit 2
bit 1
bit 0
!
Содержание ML63611
Страница 9: ...Chapter 1 Overview...
Страница 33: ...Chapter 2 CPU and Memory Spaces...
Страница 42: ...Chapter 3 CPU Control Functions...
Страница 49: ...Chapter 4 Interrupt INT...
Страница 62: ...Chapter 5 Clock Generator Circuit OSC...
Страница 71: ...Chapter 6 Time Base Counter TBC...
Страница 75: ...Chapter 7 Timers TIMER...
Страница 99: ...Chapter 8 100 Hz Timer Counter 100HzTC...
Страница 103: ...Chapter 9 Watchdog Timer WDT...
Страница 108: ...Chapter 10 Ports INPUT I O PORT...
Страница 140: ...Chapter 11 Melody Driver MELODY...
Страница 152: ...Chapter 12 Serial Port SIO...
Страница 179: ...Chapter 13 LCD Driver LCD...
Страница 200: ...Chapter 14 Battery Low Detect Circuit BLD...
Страница 204: ...Chapter 15 Power Supply Circuit POWER...
Страница 215: ...Chapter 16 A D Converter ADC...
Страница 238: ...Appendixes...
Страница 271: ...ML63611 User s Manual First Edition May 2001 Second Edition June 2001 2001 Oki Electric Industry Co Ltd PEUL63611 02...