University of Kashan Faculty of Electrical and Computer Engineering Department of Computer Engineering. Lecture note 2

Transcription

1 University of Kashan Faculty of Electrical and Computer Engineering Department of Computer Engineering Lecture note 2 Memory and IO Interfacing to & An Introduction to AVR Microcontrollers Hossein Sabaghian-Bidgoli hsabaghianb@gmail.com Fall 2014 Outlines Memory Connections (continue) Address Bit Map Memory Map Full and Partial Decoding IO Connections The AVR Microcontrollers: History and Features (Chapter 1) 2 Microprocessors University of Kashan 1

2 Memory and IO Connections How to Connect,, IO and the other peripherals Data BUS General Purpose Micro processor Address BUS Timer Serial COM Port IO Port Control BUS Memory Connection Generally should be connected Data to data Address to address Wr to wr Rd to rd Mreq to cs 4 Microprocessors University of Kashan 2

3 Memory connection (cont.) If only one chip Full size (64 kb capacity) ~A0 ~A0 64 kb Memory connection (cont.) If capacity was 32 kb composed with area is from h to 7FFFh ~A0 ~A0 32 kb 3

4 Memory Connection : : : : : : 4000h ~4FFFh 7 Microprocessors University of Kashan Memory connection (cont.) There is two 32 kb Problem: Bus Conflict. The two memory chips will provide data at the same time when microprocessor performs a memory read. Solution: Use address line as an arbiter. If outputs a logic 1 the upper memory is enabled (and the lower memory is disabled) and vice-versa. 4

5 Memory connection (cont.) There is two 32 kb applied to select one chip Two area is from h to 7FFFh (1) and 8000h to (2) ~A0 ~A kb 2 32 kb ~A0 Memory connection (cont.) 32 kb and 32 kb doesn t have wr signal ~A0 ~A0 32 kb 32 kb ~A0 5

6 Memory connection (cont.) There is 4 memory chip and applied to chip selection En S0 S1 Address Bit Map Selects chip Selects location within chips to A0 (HEX) h 4000h AA AA Memory Chip 7FFFh 8000h BFFFh C000h

7 Memory Map Represents the memory type Address area of each memory chip Empty area En S0 S1 h 4000h 7FFFh 8000h BFFFh C000h 16k 1 16k 2 16k 3 16k Memory Map Empty Area cann t write and read Read op. returns FFh value (usualy) Write op. cann t store any value on it h 4000h Empty En S0 S1 7FFFh 8000h BFFFh C000h 2 3 7

8 Memory Map Empty Area cann t write and read Read op. returns FFh value (usualy) Write op. cann t store any value on it h 4000h Empty En S0 S1 7FFFh 8000h BFFFh C000h Empty Full and Partial Decoding Full (exhaust) Decoding All of the address lines are connected to any memory/device to perform selection Absolute address : any memory location has one address Partial Decoding When some of the address lines are connected the memory/device to perform selection Results into roll-over addresses (fold back or shading). Roll-over address : any memory location has more than one address 8

9 Partial Decoding ~A12 has no connection Then doesn t play any role in addressing What is the Memory and Address Bit map? A11~A0 A11~A0 4 kb ~A12 X Partial Decoding Every memory location has more than one address For example first location has addresses: h 1000h 2000h 3000h Roll-over Address.. F000h h 0FFFh 1000h 1FFFh 2000h 2FFFh 3000h F000h to A0 (HEX) Memory Chip A11~A0 ~A12 X 4 kb A11~A0 X000h XFFFh xxxx xxxx 9

10 Partial Decoding A12 only connected to A13 has no connection What is the memory map? A11~A0 4 kb 8 kb A13 X Z80 Partial Decoding 8 roll-over address for 4 roll-over address for A13 X 4 kb A11~A0 8 kb xxx 0xxx X0x0 X0x Memory Chip 10

11 11 Partial Decoding Memory Chip 0xxx 0xxx 4k X0x0 X0x1 8k h 1FFFh h 0FFFh 1000h 1FFFh 2000h 2000h 2FFFh 3000h 4000h 5FFFh 4000h 4FFFh 5000h 5FFFh 6000h 7FFFh 6000h 6FFFh 7000h 7FFFh 8000h 9FFFh F000h A000h BFFFh C000h DFFFh E000h 4 kb Z80 A11~A0 8 kb X A13 Conflict Partial Decoding Memory Chip 0xxx 0xxx 4k X1x0 X1x1 8k h 1FFFh h 0FFFh 1000h 1FFFh 2000h 2000h 2FFFh 3000h 4000h 5FFFh 4000h 4FFFh 5000h 5FFFh 6000h 7FFFh 6000h 6FFFh 7000h 7FFFh 8000h 9FFFh F000h A000h BFFFh C000h DFFFh E000h 4 kb Z80 A11~A0 8 kb X A13 Conflict

12 12 Full (exhaustive) decoding Y0 Y1 Y2 Y3 Y6 Y4 Y7 Y5 C B A G2A G2B G EP 8k 8 CE 6116 RWM 2k 8 A10~A0 A10~A0 A13 A12 A h-07ffh 0800h-0FFFh 1000h-17FFh 1800h-1FFFh 2000h-27FFh Memory Chip Partial decoding Y0 Y1 Y2 Y3 Y6 Y4 Y7 Y5 C B A G2A G2B G EP 8k 8 CE 6116 RWM 2k 8 A10~A0 A10~A0 A13 h-1fffh 2000h Memory Chip x 001x x000 x111 GND VCC

13 A simple output port : A0 D7 D6 D5 D4 D3 D2 D1 D0 OUT (03), A D0 D1 D2 D3 D4 74LS373 D5 D6 D7 Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 LE IORQ IO A 7 A 6 A 5 A 4 A 3 A 2 A 1 A 0 A simple input port : A0 D7 D6 D5 D4 D3 D2 D1 D0 IN A, (02) Y0 Y1 Y2 Y3 Y4 Y5 Y6 Y7 A0 A1 A2 A3 74LS244 A4 G1 G2 A5 A6 A7 5V IORQ IO A 7 A 6 A 5 A 4 A 3 A 2 A 1 A 0 13

14 Microcontroller Microprocessor = on a single chip. ALU + registers + control + Micro-computer = small computer up + I/O + memory + peripheral + Microcontroller (uc) u-computer on a single chip of silicon 27 Microprocessors University of Kashan Microprocessors vs. Microcontrollers Microprocessors General Purpose Data BUS General Purpose Micro processor Address BUS Timer Serial COM Port IO Port Control BUS Microcontrollers Embedded system Fix amount of on-chip,, I/O Lower cost, power and space Single application One application software is burned into Serial Port Timer I/O 28 Microprocessors University of Kashan 14

15 Most common microcontrollers 8-bit microcontrollers H PIC AVR 32-bit microcontrollers PIC32 ARM Classic AVR Mega Tiny Special Purpose 29 Microprocessors University of Kashan AVR internal architecture 40 PIN DIP PROG Program Bus (XCK/T0) PB0 (T1) PB1 (INT2/AIN0) PB2 (OC0/AIN1) PB3 (SS) PB4 (MOSI) PB5 (MISO) PB6 (SCK) PB7 RESET VCC Bus 10 GND 11 XTAL2 12 XTAL1 13 (RXD) PD0 14 (TXD) PD1 15 (INT0) PD2 16 (INT1) PD3 17 (OC1B) PD4 18 (OC1A) PD5 19 (ICP) PD6 20 OSC MEGA32 Interrupt Unit PA0 (ADC0) PA1 (ADC1) EEP PA2 (ADC2) PA3 (ADC3) PA4 (ADC4) PA5 (ADC5) PA6 (ADC6) PA7 (ADC7) AREF AGND AVCC PC7 (TOSC2) PC6 (TOSC1) PC5 (TDI) PC4 (TDO) PC3 (TMS) PC2 (TCK) PC1 (SDA) Ports PC0 (SCL) PD7 (OC2) Timers Other Peripherals I/O PINS 30 15

16 Classic AVR e.g. AT90S2313, AT90S4433 Mega AVR different groups e.g. ATmega8, ATmega32, ATmega128 Tiny e.g. ATtiny13, ATtiny25 Special Purpose AVR e.g. AT90PWM216,AT90USB The AVR part numbers AT90S4433 ATmega1280 Atmel Classic group Flash =4K Atmel group Flash =128K AT90CAN128 ATtiny44 Atmel Special purpose group Flash =4K Atmel Tiny group Flash =4K 33 16

17 Choosing a Microcontroller Meeting the computing needs of the task efficiently and cost effectively Speed, the amount of and, the number of I/O ports and timers, size, packaging, power consumption Easy to upgrade Cost per unit Availability of software development tools Assemblers, debuggers, C compilers, emulator, simulator, technical support Wide availability and reliable sources for the microcontroller. The End Questions? 35 Microprocessors University of Kashan 17