Nuts & Volts - February 2006

➦ Figure 4. 440 Hz Music Tone generator.

The 12V programming high-voltage Vpp is generated by a voltage regulator VR1 (317LZ) through a precision resistor divider made from R1 and R2. These two resistors are specified at 1% tolerance to get accurate voltage output.

Vpp is then applied to the chip

RESET pin only after power-up and chip reset. Transistor pair Q1,Q2 acts as a switch to block or allow Vpp to go through under the control 4051 port pin P1.3. When P1.3 is low, both Q1 and Q2 are cut off, so the pull-down resistor R6 provides a way to reset the ATtiny11 to ground. When P1.3 is high, both Q1 and Q2 are turned on and the 12 Vpp is applied to enable the chip’s programming mode.

Ceramic resonator CR1 clocks the 4051 MCU, allowing it to operate at 9600 bps. LED1 indicates the programming status.

In order to make the programmer more flexible, its power supply is designed to be either 9 VAC or 12. 5 VDC. The bridge rectifier DF01 and low voltage regulator VR2 (78L05) provide +5V power for all chips. Capacitors C2 and C4 are used to smooth the DC output.

With 4K bytes of Flash memory, the programmer can (barely) store the code for all necessary operations: Blank Check, Erase Chip, Read/Write flash, Read Signature bytes, and Verify programming. The lack of any extra room forces the programmer to only accept binary file input. It doesn’t accept Hex format files.

To ease this requirement, we provide a software program named HEX2BIN.EXE to let you convert your Hex file into a binary file, compatible with the programmer. Now let’s see how to use this programmer to do something with ATtiny11.

BLINKING LED

➥ Figure 5. Third Example Circuit.

The simplest application to demonstrate MCU programming is LED ON/OFF control. Figure 3 shows the actual circuit, and Listing 1 is the AVR assembly language source code.

After power-up and completing the chip reset, the LED connected to PB0 (pin 5) is alternately driven high and low, for a half second each, caus-

➦ Listing 1. Single and Double Blinking LED program.

; LED1N2.ASM: Single/Double Blinking LED program
; 1 Hz blinking LED driven by Tiny11/12 AVR working at 1 MHz
; LED is connected to AVR PortB Bit_0 (Pin 5 for ATtiny11/12)

; Double blinking LED is generated by Low-level trigger INT0
; at PortB Bit-1 (Pin 6 for ATtiny11/12)

.include “TN11def.inc”
.cseg
.org 0

; Port definitions here

rjmp
rjmp

RESET
INT0_LED2

; INT0 is used to cause double-blinking LED

RESET:

ldi
out
ldi
out
ldi
out
sbi

r16, $80
SREG, r16  ; Enable any Interrupt
r16, $40
GIMSK, r16 ; Enable INT0
r16, $00
MCUCR, r16 ; INT0 = Low-Level triggered
DDRB, 0    ; config DDRB bit-0 as output for LED

LED1:

        cbi     PORTB, 0   ; LED=ON
        RCALL   DLhalfS
        sbi     PORTB, 0   ; LED=OFF
        RCALL   DLhalfS
        rjmp    LED1      ; repeat again
;——————————————————————————————————————————————
;the delay = 1/2 sec at 1 MHz