Philips P89LPC908, P89LPC906, P89LPC907 Serial Port Mode 0 Double Buffering Must Be Disabled

Page 64

Philips Semiconductors

User’s Manual - Preliminary -

 

 

 

UART

P89LPC906/907/908

 

 

 

 

 

S1...

S16

S1...

S16

...S1

S16

S1...

S16

S1...

S16

S1...

S16

S1...S16

S1...S16

S1...

S16

S1...

S16

S1...

S16

S1

...S16

...S1

S16

 

 

Write to SBUF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Shift

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RxD (Data Out)

 

 

 

 

 

D0

D1

D2

D3

 

D4

 

D5

D6

D7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TxD (Shift

Clock)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TI

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Write to SCON (Clear RI)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RI

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Shift

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RxD

 

 

 

 

 

 

 

 

D0

 

 

D1

 

 

D2

 

 

D3

 

 

D4

 

 

D5

 

 

D6

 

 

 

D7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(Data In)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TxD (Shift

Clock)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Transmit

Receive

Figure 8-5: Serial Port Mode 0 (Double Buffering Must Be Disabled)

MORE ABOUT UART MODE 1

Reception is initiated by detecting a 1-to-0 transition on RxD. RxD is sampled at a rate 16 times the programmed baud rate. When a transition is detected, the divide-by-16 counter is immediately reset. Each bit time is thus divided into 16 counter states. At the 7th, 8th, and 9th counter states, the bit detector samples the value of RxD. The value accepted is the value that was seen in at least 2 of the 3 samples. This is done for noise rejection. If the value accepted during the first bit time is not 0, the receive circuits are reset and the receiver goes back to looking for another 1-to-0 transition. This provides rejection of false start bits. If the start bit proves valid, it is shifted into the input shift register, and reception of the rest of the frame will proceed.

The signal to load SBUF and RB8, and to set RI, will be generated if, and only if, the following conditions are met at the time the final shift pulse is generated: RI = 0 and either SM2=0 or the received stop bit =1. If either of these two conditions is not met, the received frame is lost. If both conditions are met, the stop bit goes into RB8, the 8 data bits go into SBUF, and RI is activated.

TX Clock

 

 

 

 

 

 

 

 

 

 

 

Write to SBUF

 

 

 

 

 

 

 

 

 

 

 

Shift

 

 

 

 

 

 

 

 

 

 

Transmit

TxD

 

 

 

 

 

 

 

 

 

 

 

Bit

D0

D1

D2

D3

D4

D5

D6

D7

Stop Bit

 

 

TI

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

INTLO = 0

INTLO = 1

RX Clock

 

 

 

 

 

 

 

 

 

 

 

RxD

÷ 16 Reset

Start Bit

D0

D1

D2

D3

D4

D5

D6

D7

Stop Bit

Shift

 

 

 

 

 

 

 

 

 

 

Receive

 

 

 

 

 

 

 

 

 

 

 

RI

 

 

 

 

 

 

 

 

 

 

 

Figure 8-6: Serial Port Mode 1 (Only Single Transmit Buffering Case Is Shown)

2003 Dec 8

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Page 63 Page 65
Contents User Manual Table of Contents Brownout Detection Power-On Detection Power Reduction Modes Power-On reset code execution103 List of Figures List of Figures PIN Configurations P89LPC906Logic Symbols Product ComparisonBlock Diagram P89LPC906 KB Code FlashCPU Oscillator DividerBlock Diagram P89LPC907 UartByte Data RAM ClockBlock Diagram P89LPC908 Data RAM PortPIN Descriptions P89LPC906 PIN Descriptions P89LPC907 P1.0TxD P1.2PIN Descriptions P89LPC908 Keyboard Input P1.0 P1.5P1.1 RxDSpecial function registers Special function registers table P89LPC906MSB LSB Hex Special function registers table P89LPC907 CMP1 Cmpref TRIM.5 TRIM.4 TRIM.3 TRIM.2 TRIM.1 TRIM.0 WDCON# Special function registers table P89LPC908 KB2 KB6 KB5 KB4 TL0 Memory Organization DataSFR CodeEnhanced CPU Clock DefinitionsCPU Clock Oscclk LOW Speed Oscillator Option P89LPC906Oscillator Option SELECTION- P89LPC906 Clock Output P89LPC906ON-CHIP RC Oscillator Option Watchdog Oscillator OptionCPU Clock Cclk Wakeup Delay BIT Symbol FunctionExternal Clock Input Option P89LPC906 CPU Clock Cclk Modification Divm RegisterLOW Power Select P89LPC906 High freqMed freq Low freqCPU Clocks Flag Bits Address Enable Bits Priority Ranking Interrupt Priority StructureSummary of Interrupts P89LPC906 Description Interrupt ArbitrationExternal Interrupt Inputs External Interrupt PIN Glitch SuppressionSummary of Interrupts P89LPC907,P89LPC908 Description TI & RIBopd EBO Rtcf Kbif Interrupts Port Configurations QUASI-BIDIRECTIONAL Output ConfigurationNumber of I/O Pins Available Clock Source Reset Option RSTOpen Drain Output Configuration Port latch dataINPUT-ONLY Configuration PUSH-PULL Output ConfigurationPort 0 Analog Functions Strong Port latch data Port pin Input data Glitch rejectionPort Output Configuration P89LPC907 Port Output Configuration P89LPC906Port Output Configuration P89LPC908 Ports Ports Tmod TMOD.7TMOD.6 TMOD.3Overflows. Mode ModeTamod P89LPC907 TAMOD.7-1Tcon Pclk T0C/T = Overflow TLn THn TFn Interrupt T0 PinT0C/T = Overflow THn TFnPclk TL0 Timer Overflow Toggle Output P89LPC907TR0 ENT0 Pclk TH0 Timers 0 REAL-TIME Clock Source FOSC2 FOSC1 FOSC0 RTCS10 UCFG1.2 UCFG1.1 UCFG1.0 Cclk Frequency RTC Clock FrequencyXclk Divm CclkRC Oscillator/DIVM WDT Oscillator/DIVMUndefined External clock/DIVMChanging RTCS1-0 Reset Sources Affecting the REAL-TIME ClockREAL-TIME Clock INTERRUPT/WAKE UP Rtccon REAL-TIME CLOCK/SYSTEM Timer Brownout Detection Power Reduction Modes POWER-ON DetectionBrownout Options Power Reduction Modes Pcon Pcona Power Monitoring Functions Uart ModesSFR Space Baud Rate Generator and SelectionUpdating the BRGR1 and BRGR0 Sfrs SFR Locations for UARTs Break Detect Framing Error Brgcon Scon More about Uart Mode SstatSerial Port Mode 0 Double Buffering Must Be Disabled Framing Error and RI in Modes 2 and 3 with SM2 = FE and RI when SM2 = 1 in Modes 2More about Uart Modes 2 PCON.6 RB8 SMOD0Double Buffering Double Buffering in Different Modes9TH BIT BIT 8 in Double Buffering Modes 1, 2 Transmission with and without Double BufferingMultiprocessor Communications Automatic Address RecognitionUart Uart POWER-ON Reset Code Execution Block Diagram of ResetRstsrc Comparator Configuration Comparator and Power Reduction Modes Internal Reference VoltageComparator Interrupt CIN1A CO1 CMP1 CmprefComparator Configuration Example Analog Comparators Kbpatn KbconKbmask Watchdog Function Watchdog timer configurationWdte Wdse Function Feed Sequence Wdcon P89LPC906/907/908 Watchdog Timeout Values PRE2-PRE0Watchdog Timer in Timer Mode Prescaler Reset PclkWatchdog Control registerPower Down Operation Watchdog Clock SourcePrescaler CLKWatchdog Timer Watchdog Timer Dual Data Pointers Software ResetAUXR1 MOVCA, @A+DPTR Move code byte relative to Dptr to the accumulatorMOVXA, @DPTR MOVX@DPTR, aFeatures Using Flash AS Data StorageGeneral Description Introduction to IAP-LITEFlash Program Memory Fmcon Accessing Additional Flash Elements Assembly language routine to erase/program all or part of aReading Additional Flash Elements ERASE-PROGRAMMING Additional Flash ElementsUCFG1 Fmadrl Conf UCFG1 User Configuration BytesP89LPC906 User Security Bytes SECxAddress xxxxh Unprogrammed value 00hBootvec BootstatArithmetic LogicalMnemonic Description Bytes Cycles Hex Code Data TransferBoolean BranchingReti B8-BFD8-DF Miscellaneous2003 Dec Initial release 104 Index Dual Data Pointers Port 0 12, 13 SFR 109 P89LPC906/907/908
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