One day I’ve got ARM LPC2148 chip in my hands. The Philips LPC2148 is an ARM7TDMI-S based high-performance 32-bit RISC Microcontroller with Thumb extensions 512KB on-chip Flash ROM with In-System Programming (ISP) and In-Application Programming (IAP), 32KB RAM, Vectored Interrupt Controller, Two 10bit ADCs with 14 channels, USB 2.0 Full Speed Device Controller, Two UARTs, one with full modem interface.
Two I2C serial interfaces, Two SPI serial interfaces Two 32-bit timers, Watchdog Timer, PWM unit, Real Time Clock with optional battery backup, Brown out detect circuit General purpose I/O pins. CPU clock up to 60 MHz, On-chip crystal oscillator and On-chip PLL.
Looks like it can be powerful thing in good hands.
I decided to test its power, so I needed development board, which could I use for my experiments. Because I wanted to have more universal board, so I faced few problems â€“ PCB tracing. My purpose was to make this PCB at home, so I didnâ€™t want to waste time while tracing big board with many tracks. There were two ways of making it: make one big board with complicated tracing of PCB tracks, or split it in two parts. I’ve chosen second one. In a first stage I made ARM-mini board where I placed the ARM chip and two resonant clock sources: one for core and another for RTC (Real Time Clock). By doing this I only needed one sided PCB. Also I could reduce the number of pins from 64 to 51. Of course I sacrificed VDDA ad GNDA pins by connecting them to digital pat voltage source.
Schematic and PCB is done by using Eagle software. It can be downloaded from http://www.cadsoft.de/. You can use it freely as it is board size limited – 8Ã—10 cm, and make two layer PCBâ€˜s. Also this tool is available for Windows, Linux or Mac operation systems. .If you want make bigger boards, you should purchase it as this is really good software for intermediate projects.
PCB doesnâ€™t look very good; I think because I used new UV light expose box, so exposure time, o maybe there wasnâ€™t enough of development of photo resist. But as all tracks are OK I decided to leave it as it is.
Completed and soldered mini board. Soldering wasnâ€™t as hard as it seemed so. I used iron, solder and plenty of flux. Results you can see bellow.
Here you can see how I created adequate 3D model of my ARM mini with Eagle3D. You can download Eagle3D from http://www.matwei.de. With it you can create very realistic looking PCB layouts or even animation.
I have also created eagle library element to use ARMmini for future development boards.
I used this ARMmini board for LPC2148 development board manufacturing.
Thats it for now.
Download PCB files here: ARM Mini Eagle files