peripheral device - Microcomputer Applications - Exam, Exams of Microcomputers

Download peripheral device - Microcomputer Applications - Exam and more Exams Microcomputers in PDF only on Docsity! Cork Institute of Technology Bachelor of Engineering in Applied Electronic Design - Stage 3 Bachelor of Engineering in Electronic Automation and Robotics - Stage 3 Bachelor of Engineering in Communication Systems - Stage 3 (NFQ Level 7) Autumn 2006 Microcomputer Applications (Time: 2 Hours) Answer THREE questions. Examiners: Mr. F. O’Reilly Mr. P. Watson Mr. J. Berry Dr. R. O Dubhghaill Q1 (a) Compare and contrast microprocessors and micro-controllers. What advantages, disadvantages does each have? [8 marks] (b) For the following applications identify, (i) Approximate no of Input & Outputs (ii) Estimate of speed/performance required. (iii) Complexity/Range of algorithms/programmes to execute. Applications • Handheld Remote Control for TV/Video. • Microwave Oven with digital timer and programmer. • PlayStation Portable (PSP) handheld games console. From the following micro-controller/microprocessors, suggest suitable models and why for each of the above applications. Embedded 8051 Low Cost IC, Motorola 68000 processor, Intel Pentium 3 family, Microchip PIC. [15 marks] (c) As a member of an 8-bit micro-processor usage team, you are tasked to devise a scheme to vary the number of special registers from 200(basic model) to 800(advanced model), while being restricted to using only 8 bits(max of 256) to describe which register is in use. Can you suggest a scheme to do this? Which micro-processors/micro-controller currently use such a technique? [10 marks] [Total: 34 marks] Q2 (a) Interrupt handling is important for embedded systems. Explain what happens when an interrupt occurs in the PIC and how the interrupt should be handled. Explain what memory addresses are used, the different types of interrupts available and how they can be differentiated. [12 marks] (b) Explain the operation and configuration of Timer 2 on the PIC micro-controller. Derive the following formula for the preload value. [10 marks] Pre-load Value = Time * FOSC (Using Internal Clock) Prescalar * 4 (c) Calculate the pre-load value for the 16c74 micro-controller to generate a 4.0 kHz square wave using Timer2, showing in code how the value would be loaded in. Assume a clock of 4MHz. [12 marks] [Total: 34 marks] TABLE 1 1-1: BAUD RATE FORMULA SYNC BRGH = 0 (Low Speed) BRGH = 1 (High Speed) 0 1 (Asynchronous) Baud Rate = Fosci(64(SPBRG*1)) Baud Rate = Fosci(16(SPBRG*1)) (Synchronous) Baud Rate = Fosc/(4(SPBRG+1)) N/A TABLE 1 1-2: REGISTERS ASSOCIATED WITH BAUD RATE GENERATOR Address Name Value on: Value on Bir? | Bité | Bid | Bird | Bind | Bit2 | Bitt | Bito POR, all other BOR RESETS 38h TXSTA CSRC | 1X9 | TXEN | SYNC | — | BRGH | TRMT | TX9D | 0000 -010| 0000 -010 18h RCSTA SPEN | RX9 [ SREN| CREN | — | FERR | OERR | RX9D | 0000 -oox | 0000 -o0x 99h) ‘SPBRG Baud Rate Generator register 0000 0000 | 0000 0000 Legend REGISTE! ‘x = unknown, - = unimplemented, read as ‘0. Shaded cells are not used by the BRG. R 12-1: bit 7-6 bit 5-3 bit 2 bit 1 bit 0 ADCONO REGISTER (ADDRESS 1Fh) RWw-0 Riw-o RiW-0 RIW-0 RiW-0 RW-0 U-0 AW-O apcst | apcso | cHs2 [ cHsi [ cHso [GODONE] — ADON bit 7 bit O ADCS1:ADCSO: A/D Conversion Clock Select bits 00 = Fosc/2 ) Fosc/s 10 = Fosc/a2 11 = FRc (clock derived from the internal A/D module RC oscillator) CHS$2:CHSO: Analog Channel Select bits 000 = channel 0, (RAO/ANO) 901 = channel 1, (RAI 010 = channel 2, (RA2: 011 = channel 3, (RA3 100 = channel 4, (RA5/ 101 = channel 5, (REO/ 110 = channel 6, (REI 111 = channel 7, (RE2/AN7)(1 GO/DONE: A/D Conversion Status bit If ADON = 1 1 = AID conversion in progress (setting this bit starts the A/D conversion) 0 = A/D conversion not in progress (this bit is automatically cleared by hardware when the A/D conversion is complete) Unimplemented: Read as '0' ADON: A’D On bit 1= AID converter module is operating 0 = A/D converter module is shut-off and consumes no operating current Note 1: A/D channels 5, 6 and 7 are implemented on the PIC16C74B only. Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as 0) -n = Value at POR 1’ = Bitis set O' = Bit is cleared x = Bitis unknown REGISTER 12-2: ADCON1 REGISTER (ADDRESS 9Fh) u-0 u-0 u-0 u-0 u-0 RW-0 RW-O0 _-R/W-0 = =—7T- 7-7 = PcrG2 | PCFGt | PCFGO bit 7 bit 0 bit7-3 _ Unimplemented: Read as '0' bit 2-0 PCFG2:PCFG0: A/D Port Configuration Control bits PCFG2:PCFGO| RAO | RA1 | RAZ | RAS | RAS | REO /RE1)|RE2\)| Vrer coo A A A A A A A A_| Vow o01 A A A A_| Veer [A A A_| RAs 10 A A A A A D D D_ | Voo ot A A A A_| Veer [ D D D_ | Ras 100 A A D D A D D D_ | voo 101 A A D D | ver | D D D | RAS 11x D D D D D D D D_ | Voo A= Analog input = Digital I/O Note 1: REO, RE1 and RE2 are implemented on the PIC16C74B only. Legend: R = Readable bit W = Writable bit U = Unimplemented bt, read as ‘0° -n= Value at POR ‘1 = Bitis set ‘0 = Bitis cleared x = Bit s unknown