More on MSP430 Programming

1. More on MSP430 Programming

2. Administration • Week 17 (6/8): Term Project workshop • No class, I will be here to help you work on your term project • Deadline for the lab exercises • Demo and turn on your codes before 2008/6/8 23:59

3. Outline • More peripherals • Watchdog Timer • Supply Voltage Supervisor (SVS) • Direct Memory Access (DMA) • Flash Memory Controller • External 8Mbit Flash Memory: M25P80 • Temperature/humidity sensor: SHT11 • Low Power Modes • MSP430 Software Coding Techniques

4. Watchdog Timer • Most embedded systems need to be self-reliant • watchdog timer is a hardware • that can watch for system hang • reset the processor if any occur • It is a counter • counts down from some initial value to zero • must select a counter value • periodically restarts the counter • before it counts to zero • If it counts to zero • trigger a system reset

5. Watchdog timer on MSP430 • 16-bit timer, four software-selectable time intervals • (clock source)/32768, (clock source)/8192, (clock source)/512, (clock source)/64 • Can be configured into watchdog mode or interval mode • Watchdog mode: generate a reset when timer expired • Interval mode: generate a interrupt when timer expired • When power up, it is automatically configured in the watchdog mode • Initial ~32-ms reset interval using the DCOCLK. • Must halt or setup the timer at the beginning

6. Usage • Stop watchdog timer • WDTCTL = WDTPW + WDTHOLD; • Change watchdog timer interval • WDTCTL = WDTPW+WDTCNTCL+(interval) • Periodically clear an active watchdog • WDTCTL |= WDTPW+WDTCNTCL ClockSource/32768: ClockSource/8192: WDTIS0 ClockSource/512: WDTIS1 ClockSource/64: WDTIS0 + WDTIS1 Password-protected: must include the write password

7. Example Select clock source: ACLK Select timer interval: (clock source)/8192 = 32768Hz/8192 = 4Hz Reset watchdog counter Reset watchdog counter

8. Supply Voltage Supervisor • Monitor the AVCC supply voltage or an external voltage • Can be configured to set a flag or generate a reset when the supply voltage or external voltage drops below a user-selected threshold • Comparison • 14 threshold levels for AVCC • External input: SVSIN • compared to an internal level of approximately 1.2 V

9. SVS Register This bit will set to 1 if the voltage is below threshold • SVSCTL • VLDx

10. Example

11. Direct Memory Access • Transfers data from one address to another, without CPU intervention • Increase throughput and decrease power consumption • DMA on MSP430 • Three independent transfer channels • Configurable transfer trigger selections • Timer, UART, SPI, ADC, ….. • Byte or word and mixed byte/word transfer capability • Single, block, or burst-block transfer modes • Block sizes up to 65535 bytes or words

12. DMA Addressing Modes Source/destination address can be configured to be unchange/increment/decrement after each transfer

13. DMA Transfer Modes • Six transfer modes • Single transfer, block transfer, burst-block transfer, repeated single transfer, repeated block transfer, repeated burst-block transfer • Single transfer • Each transfer requires a separate trigger, DMA is disable after transfer • Must re-enable DMA before receive another trigger • Repeated single transfer: DMA remains enable • Another trigger start another transfer • Block transfer • Transfer of a complete block after one trigger, DMA is disable after transfer • Repeated block transfer: DMA remains enable, • Another trigger start another transfer • Burst-block transfer • Block transfers with CPU activity interleaved, • Repeated burst-block transfer: DMA remains enable • Keep transferring • CPU executes at 20% capacity

14. DMA Triggers A transfer is triggered when the CCIFG flag is set A transfer is triggered when USART0 receives new data A transfer is triggered when USART0 is ready to transmit new data A transfer is triggered by an ADC12IFGx flag.

15. Initialization And Usage • Example (DMACTL0) Configure transfer trigger (DMA0SA) Configure source address (DMA0DA) Configure destination address (DMACTL1) Select transfer mode, addressing mode, and/or other setting, and enable DMA (DMA0SZ) Configure block size Use DMA to transfer a string to UART buffer, send it out through UART Repeated single transfer Source address is incremented source byte to destination byte DMA enable

16. Others About DMA • DMA Transfer Cycle Time • DMA transfers are not interruptible by system interrupts

17. Flash Memory Controller • MSP430 flash memory is bit-, byte-, and word-addressable and programmable • Segment erase and mass erase • Minimum VCC voltage during a flash write or erase operation is 2.7 V • Program code are stored in the flash • Unused flash memory can be use to store other data

18. Flash Memory Characteristics • Write in bit-, byte-, or word; erase in segment • MSP430F1611 segment size • Information memory: 128 bytes • Main memory: 512 bytes • Erase • Make every bit in the segment as logic 1 • Write • Generate logic 0 in the memory • Flash endurance • Maximum erase/write cycles • In MSP430 datasheet • Minimum: 10000 cycles • Typical: 100000 cycles

19. Flash Memory Operation • Read, write, erase mode • Default mode is read mode • Write/erase modes are selected with the BLKWRT, WRT, MERAS, and ERASE bits • Flash Memory Timing Generator • Sourced from ACLK, SMCLK, or MCLK • Must be in the range from ~ 257 kHz to ~ 476 kHz • Incorrect frequency may result in unpredictable write/erase operation

20. Flash Memory Erase • Example Disable all interrupts and watchdog (FCTL2) Setup timing generator (FCTL3) Unlock flash memory (FCTL1) Configure the operation Re-enable interrupt and watchdog (FCTL3) lock flash memory Wait until erase complete Dummy write Password protected

21. Flash Memory Write • Example Disable all interrupts and watchdog (FCTL2) Setup timing generator (FCTL3) Unlock flash memory (FCTL1) Configure the operation Re-enable interrupt and watchdog (FCTL3) lock flash memory Wait until write complete Write to specific memory address Password protected

22. Outline • More peripherals • Watchdog Timer • Supply Voltage Supervisor (SVS) • Direct Memory Access (DMA) • Flash Memory Controller • External 8Mbit Flash Memory: M25P80 • Temperature/humidity sensor: SHT11 • Low Power Modes • MSP430 Software Coding Techniques

23. M25P80 • External Flash storage on Taroko • 8 Mbit Flash Memory • SPI Bus Compatible Serial Interface • Memory organization • 16 sectors • Each sector containing 256 pages • Each page is 256 bytes • Operations • Erase: set all bit to 1 • Program(write): reset some bits to 0 • Read: read the content of the flash

24. Signals And Connections

25. SPI • Master–Slave mode • Synchronous protocol • All transmissions are referenced to a common clock • Clock generated by the master (MCU) • Four main signals • Master Out Slave In (MOSI): data from master to slave • Master In Slave Out (MISO): data from slave to master • Serial Clock (SCLK or SCK): clock • Chip Select (CS): select particular peripheral when multiple peripherals are connected to master

26. Memory organization

27. Instruction Set

28. Operation • Read Data Bytes (READ) • Read data from memory • Page Program • Write bytes to a page • Up to 256 bytes each time • Sector Erase • sets all bits to 1 inside the chosen sector • Bulk Erase • Erase (sets to 1) all memory data

29. Device Driver • Download here • http://nslab.ee.ntu.edu.tw/courses/wsn-labs-spring-09/labs/m25p80Driver.rar • Important functions in hal_m25p80.c • void halM25p80Init(void) • void m25p80PowerUp(void); • void m25p80PowerDown(void); • void m25p80PageWrite(UINT16 add, UINT8 *buff, UINT8 size); • void m25p80PageRead(UINT16 add, UINT8 *buff, UINT8 size); • void m25p80SectorErase(UINT8 add); • void m25p80BulkErase(void);

30. Functions • void m25p80PageWrite(UINT16 add, UINT8 *buff, UINT8 size); • address range from 0x0000 to 0x0fff (4096 pages in total) • At most 256 bytes • Always write from the beginning of the page • void m25p80PageRead(UINT16 add, UINT8 *buff, UINT8 size); • address range from 0x0000 to 0x0fff (4096 pages in total) • At most 256 bytes • Always read from the beginning of the page • void m25p80SectorErase(UINT8 add); • address range from 0x00 to 0x0f (16 sectors in total) • Each sector is 65536 bytes

31. Example

32. Outline • More peripherals • Watchdog Timer • Supply Voltage Supervisor (SVS) • Direct Memory Access (DMA) • Flash Memory Controller • External 8Mbit Flash Memory: M25P80 • Temperature/humidity sensor: SHT11 • Low Power Modes • MSP430 Software Coding Techniques

33. SHT11 • Relative humidity and temperature sensors • Digital output • Manufacturer defined interface • two wires bi-direction Use a GPIO pin as clock (SCK), it is always output direction Use another GPIO as DATA, dynamic setting it to input(read) or output(write) direction

34. Taroko Connections

35. Start Transmission and Send Command • How to start • What are the commands available

36. An Example: SHT11 Pull-up Data pin in output direction Set data pin to input direction, then SHT11 controls the DATA line • Timing diagram

37. Software Implementation

38. Software Implementation

39. Software Implementation

40. Convert to Physical Values • 12-bit humidity, 14-bit temperature • Temperature • Humidity

41. Device Driver • Download here • http://nslab.ee.ntu.edu.tw/courses/wsn-labs-spring-09/labs/sht11Driver.rar • Important functions in SHT1x_sensirion.c • void sht1xInit(); • void sht1xReset(); • char sht1xMeasure(unsigned char *p_value, unsigned char *p_checksum, unsigned char mode); • void sht1xCalculate(float *p_humidity ,float *p_temperature);

42. Functions • char sht1xMeasure(unsigned char *p_value, unsigned char *p_checksum, unsigned char mode); • mode: { TEMP, HUMI } • Store measured value to *p_value • Store 8-CRC checksum to *p_checksum • void sht1xCalculate(float *p_humidity ,float *p_temperature); • Convert measured value to physical value • Put the measured value in *p_humidity, *p_temperature • Result will also place in *p_humidity, *p_temperature (overwrite)

43. Example

44. Outline • More peripherals • Watchdog Timer • Supply Voltage Supervisor (SVS) • Direct Memory Access (DMA) • Flash Memory Controller • External 8Mbit Flash Memory: M25P80 • Temperature/humidity sensor: SHT11 • Low Power Modes • MSP430 Software Coding Techniques

45. MSP430 Clock System high-frequency oscillator (optional) MSP430 digitally controlled oscillator Clock Signals Clock Modules CPU DCOCLK MCLK: Master Clock XT2CLK SMCLK: Sub-main clock Peripherals: Timer, UART, … LFXT1CLK ACLK: Auxiliary clock 32.768KHz fixed rate Low-frequency/high-frequency oscillator

46. MSP430 Power Consumption Characteristics • Current increase with clock frequency • Current increase with supply voltage • Supply voltage vs frequency • More active peripherals means more current consumption

47. Operating Modes • MSP430 has six operating modes • The operating modes take into account three different needs • Ultralow-power • Speed and data throughput • Minimization of individual peripheral current consumption • Turn off different clocks in different operating mode

48. Operating Modes

49. Typical Current Consumption

50. Low Power Modes • Different low power mode disable different clocks • Peripherals operating with any disabled clock are disabled until the clock becomes active • Wake up is possible through all enabled interrupts • Returns to the previous operating mode if the status register value is not altered during the ISR