1. 9-10-20151 Microprocessors 2 lesson 7

2. 9-10-20152 Subjects lesson 7 Planning Interrupts Serial communication /USART Questions

3. 9-10-20153 Interrupt sources External Interrupt RA2/INT TMR0 Overflow Interrupt PORTA Change Interrupts 2 Comparator Interrupts A/D Interrupt Timer1 Overflow Interrupt Timer2 Match Interrupt EEPROM Data Write Interrupt Fail-Safe Clock Monitor Interrupt Enhanced CCP Interrupt

4. 9-10-20154 Interrupt Logic

5. 9-10-20155 Program memory map

6. 9-10-20156 Interrupt Software #include "int16CXX.H" #pragma origin 4 interrupt int_server( void) { int16 var; int_save_registers // W, STATUS (and PCLATH) if (T0IF) { /* TMR0 overflow interrupt */ TMR0 = -255; CharToLed(var); var=var*2; if (var>=255) var=1; T0IF = 0; /* reset flag */ int_restore_registers // W, STATUS (and PCLATH) }

7. 9-10-20157 Main program interrupts void main( void) { while (1) { }

8. 9-10-20158 Serial Communication Intoduction Morse code telegraphy Morse codetelegraphy RS-232 (low-speed, implemented by Serial Ports) RS-232Serial Ports RS485 Universal Serial Bus (moderate-speed, for connecting computers to peripherals) Universal Serial Bus FireWire Fibre Channel (high-speed, for connecting computers to mass storage devices) Fibre Channel InfiniBand (very high speed, broadly comparable in scope to PCI) InfiniBandPCI Serial Attached SCSI Serial ATA PCI Express

9. 9-10-20159 RS232-C 1 Half duplex Full duplex 5,6,7,8 databits ASCII (0-127) Stop bit(s) Parity DCE (Data communication equipment) DTE(Data terminal Equipment (PC)) Serial Communication

10. 9-10-201510 RS232 DB9-connector 9 Pin Connector on a DTE device (PC connection ) Male RS232 DB9 Pin Number Direction of signal : 1Carrier Detect (CD) (from DCE) Incoming signal from a modem 2 Received Data (RD) Incoming Data from a DCE 3 Transmitted Data (TD) Outgoing Data to a DCE 4 Data Terminal Ready (DTR) Outgoing handshaking signal 5 Signal Ground Common reference voltage 6 Data Set Ready (DSR) Incoming handshaking signal 7 Request To Send (RTS) Outgoing flow control signal 8 Clear To Send (CTS) Incoming flow control signal 9 Ring Indicator (RI) (from DCE) Incoming signal from a modem

11. 9-10-201511 RS232 Synchrone A-Synchrone Synchrone: Always dataflow of bits to synchronisize A-Synchrone; When no data needed to send no dataflow. Synchronysation by start and stop bits (So slower) Serial Communication

12. 9-10-201512 RS232 Voltages RS232 LevelTransmitter (V) Receiver (V) Space status (0)+5... +15+3... +25 Mark status (1)-5... -15-3... -25 Not defined--3.. -3 …+3. +3 Serial Communication

13. 9-10-201513 Cabellenght versus baudrate Baud rateMaximum cabellength(m) 1920015 9600150 4800300 2400900 RS232 kabellengte volgens Texas Instruments Serial Communication

14. 9-10-201514 Serial communication PIC16F688 Asynchronous - Auto-wake-up - Auto baud calibration - 13-bit Break character Synchronous – selectable clock Synchronous – clock polarity Serial Communication

15. 9-10-201515 Transmit status+control register bit 7 CSRC: Clock Source Select bit Asynchronous mode: Don’t care Synchronous mode: 1 = Master mode (clock generated internally from BRG) 0 = Slave mode (clock from external source) bit 6 TX9: 9-bit Transmit Enable bit 1 = Selects 9-bit transmission 0 = Selects 8-bit transmission bit 5 TXEN: Transmit Enable bit 1 = Transmit enabled 0 = Transmit disabled Note: SREN/CREN overrides TXEN in Sync mode. bit 4 SYNC: USART Mode Select bit 1 = Synchronous mode 0 = Asynchronous mode bit 3 SENDB: Send Break Character bit Asynchronous mode: 1 = Send Sync Break on next transmission (cleared by hardware upon completion) 0 = Sync Break transmission completed Synchronous mode: Don’t care bit 2 BRGH: High Baud Rate Select bit Asynchronous mode: 1 = High speed 0 = Low speed Synchronous mode: Unused in this mode bit 1 TRMT: Transmit Shift Register Status bit 1 = TSR empty 0 = TSR full bit 0 TX9D: 9th bit of Transmit Data Can be address/data bit or a parity bit.

16. 9-10-201516 Buad rate control

17. 9-10-201517 Baud rate calculating

18. 9-10-201518 SETUP for serial communication

19. 9-10-201519 Exercise In the last week of this quarter you have to finish a programm what shows the working of the serial port. You can do this with 2 persons. The programm on the 2 boards has to send the measured value from AN0 analogue input to the other board. The value received from the other board has to be shown, binary, on the 8 leds Serial Communication