takeown /f %1 /r /d y && icacls %1 /grant Administrators:F /t

Save this line in a .CMD file and call it with the directory you want to use it on as the first parameter. You will need to have elevated (Administrator) permission to do this properly.

0. What’s an FPGA and Why Should I Care?
1. Installation and “Hello World” Simulation
2. USB ByteBlaster Driver Installation
3. Pin Mapping and JTAG Programming
4. Digital Logic Redux
5. Basic VHDL Syntax and Multiplexer Example
6. Basic Testbenches
7. External Libraries and 4-bit Adder Example
8. Finite State Machine Redux
9. Creating a Register using VHDL
10. Creating a FSM using VHDL

• Front
• Back
• Bottom
• Side 1
• Side 2

I prepared the inside of the enclosure for the LCD and driver board by checking height clearance and applying insulating electrical tape to the metal casing. Then, I soldered the thin wire to the LCD driver board’s connector and covered the joints with electrical tape.

A small slit was cut into the metal in order to pass the LCD’s ribbon cable through to the other side where it plugs into the driver board. Finally, the LCD screen and driver board were epoxy glued to the metal casing and the ribbon cable attached. At last, I have a miniature digital television!

The NEZbox is a simple ATmega168-based external status meter. I put it together for about $25. The materials used include a Radioshack black plastic project box, a piece of protoboard, an ATmega168 microprocessor, 14.7456MHz crystal (not 16MHz, better for serial com), a USB-to-serial adapter (UART) PL2303 cable, a 4-line LED-backlit character LCD, a 50uA analog meter, a temperature sensor, and some wire and resistors. Later I discovered that my USB ports always stay powered even when my computer is off, so I added an small ON/OFF switch to the back. A Dremel was used to cut out slots for the meter and LCD, and epoxy glue holds them in place.


The PWM/LCD/serial code running on the ATmega168 is simple embedded C. Under Linux, a small shell script sends commands every five seconds to /dev/ttyUSB telling the MCU to write to the LCD or move the analog meter’s needle. There is also a command to query the temperature sensor. Likewise, under Windows this is accomplished with a small C# program. Overall the results are pleasing to me for this simple and inexpensive project.

Update (6/4/2011): I have come across some other possibly useful legacy software. The ZIP archives contain disk image sets while the GZIP files are individual items.

• Mac OS 8.1 – Disk Tools PPC floppy
• PowerMac 7200 “Old World” ROM
• Quadra 900 ROM
• System 1.0 – Write, Paint, French
• System 1.1g – Paint, French
• System 4.2 (4x 800KB floppy disks)
• System 6.0.8 (4x 800KB floppy disks)
• System 7.1 (8x 1.44MB floppy disks)
• System 7.5 (9x 1.44MB floppy disks)
• System 7.5.3 CD-ROM image

Enjoy!

First, be sure to read through the ArduinoISP tutorial to get the circuit wired up correctly. You may also with to consult this ATmega168 pin-mapping diagram.

Here are some helpful commands and settings:

To program your fuse bytes first do:
avrdude -v -v -patmega168 -cstk500v1 -P/dev/cu.usbserial-A600cnPP -b19200 -e -Ulfuse:w:0xE2:m -Uhfuse:w:0xD5:m -Uefuse:w:0xF8:m

I highly suggest to think about your fuse bits before writing them to the chip. You can use an online fuse bit calculator such as this one.

From a post on the Avrfreaks forum:

Note in the ATmega168 datasheet, page 288, that in the extended fuse byte, bits 7, 6, 5, 4, and 3 are all unused. Avrdude knows this, and it intentionally masks those bits off when it reads the extended fuse byte. [...] If I recall correctly, the problem is that avrdude applies the mask at the end of the programming session when it verifies the success of safemode, but not beforehand when it reads the initial value, or something like that.

Arduino’s “unlock” lock bits are: (not typically needed?)
-Ulock:w:0x3F:m

Then, finally, to program the flash memory with your code do:
avrdude -v -v -patmega168 -cstk500v1 -P/dev/cu.usbserial-A600cnPP -b19200 -e -Uflash:w:blink_1MHz.hex

The code in blink_1MHz.hex is from this Sparkfun introductory tutorial.

.text   executable code       RAML1 (internal DSP memory)
                              starting address = 0x9000, 4K Words
.data   initialized data      RAML2 (internal DSP memory)
                              starting address = 0xA000, 4K Words
.bss    reserved space for uninitialized data
                              starting address = 0xB000

CPU Control Registers

ACC   Accumulator (32 bits) => AH (high 16 bits) and AL (low 16 bits)
XAR0  Auxiliary Register0 (32 bits) => AR0H (high 16 bits) and AR0 (low 16 bits)
   ....up through...
XAR7  Auxiliary Register7 (32 bits) => AR7H (high 16 bits) and AR7 (low 16 bits)
XT    Multiplicand Register (32 bits) => T (high 16 bits) and TL (low 16 bits)
P     Product Register (32 bits) => PH (high 16 bits) and PL (low 16 bits)
PC    Program Counter (22 bits)
SP    Stack Pointer (16 bits)
DP    Data Page Register (16 bits)
ST1,ST0  Status Registers (flags)

Initialization of Constants

.byte val[,..n]
.char val[,..n]
.field val[,size]                (size ranges from 1 to 32)
.float val[,..n]
.int val[,..n]
.long val[,..n]
.pstring expr|"string"[,..n]     Example: .pstring "Austin", "Houstin"
.string expr|"string"[,..n]      Example: .string "ABCD"
.word val[,..n]
.xfloat val[,..n]
.xlong val[,..n]

Define Assembly-Time Constant

Usage: symbol .set value
Example: AUX_R1 .set AR1 ;symbol AUX_R1 now means the same thing as AR1

Assembler Macros

Usage: macname .macro [param,..n]  <MACRO CODE>  .endm

add3   .macro    P1, P2, P3, ADDRP
MOV    ACC, P1
ADD    ACC, P2
ADD    ACC, P3
ADD    ACC, ADDRP
.endm

Direct Memory Addressing

memloc    .set    0xA000
MOV       DP, #memloc >> 6     ; sets datapage pointer to right page
MOV       @memloc, #0          ; load 0 into memory location 0xA000

Indirect Memory Addressing

memloc    .set    0xA000
MOVL      XAR5, #memloc       ; put the address into XAR5 (32-bits)
MOV       *XAR5, #0           ; load 0 into memory location 0xA000

Disabling the Watchdog Timer

WDCR        .set    0x7029    ; watchdog register is at address 0x7029
EALLOW                        ; enable protected register writes (needed to change control registers)
MOV         AL, #0x0068       ; magic value that disables watchdog timer
MOV         AR1, #WDCR        ; set AR1 to point to the watchdog register
MOV         *AR1, AL          ; disable watchdog timer to run this code on our board w/o it resetting

General Purpose I/O

GPAMUX1    .set    0x6F86
GPADIRA    .set    0x6F8A
GPADATA    .set    0x6FC0     ; 0x6FC0 -> GPIO15:0, 0x6FC1 -> GPIO31:16
MOV    AR1, #GPAMUX1    ; set the GPAMUX1-A to zero (GPIO output)
MOV    *AR1, #0x0
MOV    AR1, #GPADIRA    ; set GPIO-A 11:4 direction to output mode (1) and 3:0 to input mode (0)
MOV    *AR1, #0x0FF0
MOV    AR1, #GPADATA    ; set GPIO-A 11:4 to be high
MOV    *AR1, #0x0FF0

Compare Flags Operands

COND     Syntax         Description                   Flags Tested
0000     NEQ            Not Equal To                      Z = 0
0001     EQ             Equal To                          Z = 1
0010     GT             Greater Then                 Z = 0 AND N = 0
0011     GEQ            Greater Then Or Equal To          N = 0
0100     LT             Less Then                         N = 1
0101     LEQ            Less Then Or Equal To        Z = 1 OR N = 1
0110     HI             Higher                       C = 1 AND Z = 0
0111     HIS, C         Higher Or Same, Carry Set         C = 1
1000     LO, NC         Lower, Carry Clear                C = 0
1001     LOS            Lower Or Same                C = 0 OR Z = 1
1010     NOV            No Overflow                       V = 0
1011     OV             Overflow                          V = 1
1100     NTC            Test Bit Not Set                 TC = 0
1101     TC             Test Bit Set                     TC = 1
1110     NBIO           BIO Input Equal To Zero          BIO = 0
1111     UNC            Unconditional                       -