Published:2011/8/16 21:14:00 Author:Phyllis From:SeekIC
By Tony Dixon
In the first installment of a three-part article we will look at recent developments in 32-bit ARM based microcontrollers, concentrating on those devices that are available, do not cost an arm and a leg or require a major investment in surface mount soldering equipment!
ARM stands for Advanced RISC Machine, where RISC means Reduced Instruction Set Computer. The ARM 32-bit architecture has been around for a number of years and has been used in products where low power consumption is essential such as for mobile phones and PDA’s.
Its 32-bit core is available in several guises including the ARM7, ARM9, ARM 10 and the recently announced ARMl1, each of which offers enhanced levels of computing power.
The ARM was usually only available as a microprocessor device, where it required external program and data memory to complete a system. However several companies are now offering a 32-bit ARM based microcontroller with sufficient memory options for them to be considered worthy microcontroller alternatives. Table 1 shows a selection of ARM based microcontrollers from three companies, Analog Devices, OKI Semiconductors and Philips Semiconductors. Other companies such as Atmel, NetSilicon, Samsung and Tl offer similar devices but these are usually available in larger BGA (ball grid array) packaging only, making them less suitable For hand prototyping. So v/hat’s available on the ARM market we can actually obtain and handle? Let’s have a look what a number of major manufacturers in the ARM arena have on offer.
Analog Devices
Analog Devices (www.analog.com) is not a name normally associated with microcontrollers, however they are about to change this view by creating a microcontroller product with a range of precision analogue interfaces. Elektor Electronics (leading the way!) have already published o series of articles on Analog Devices AduC812 8052 based controllers (Ref. 1). Analog Devices have released an updated range using an ARM7TDMI as the computing engine.
The ADuC702x family of devices from Analog Devices integrates a 32-bit ARM7TDMI core with a 12-bit data converter that can have up to 16 channels supporting one million samples/sec. The ADuC702X devices also feature up to four 12-bit DACs with a precision bandgap reference sensitive to 10 ppm/°C. Other peripherals include a comparator, a small programmable-logic array (PLA) for glue logic, an on-chip temperature sensor (±3°C) and a three-phase 16-bit PWM generator. Of these peripherals the programmable-logic array is the most interesting to find on a microcontroller.
A JTAG interface is provided for debugging the chip, while the UART can be used to program the Flash memory in-situ.
An on-chip oscillator will drive the ADuC702x at speeds of up to 35 MHz and is 2% accurate. An external clock is required to run at speeds up to the 45- MHz limit.
Memory options include both a 32-kByie Flash memory for the ADuC7024 and a 62-kByte Flash memory for the ADuC7026 and all include 8 kBytes of RAM. Packaging options range from a 6x6-mm, 40-lead CSP, a 64-pin LQFP and an 80-pin LQFP. These 3-V devices can operate within a temperature range of -40 to +85, or at extended temperatures up to +105, or +125°C.
Analog Devices offer a low-cost quick start development system called QuickStort, which includes a power supply, cables, evaluation board, JTAG emulator and software-development tools from Keil Software and IAR Systems. The QuickStort Development System sells for $249 and is available directly from Analog Devices.
Of the devices offered, the 64-pin and 80-pin devices are probably the most usable by our readership for their prototyping ease.
Philips
Of all the companies offering ARM microcontrollers Philips (vAvw.semiconductors.philips.com) seem to be the company pushing the ARM microcontroller the most and have already released an extensive range of microcontrollers based on a 32-bit ARM7TDMI-S core (see inset). Philips initially offered the LPC210x which featured 16 to 64 kB of RAM dependant on the device, together with 128 kB of Flash memory and all operating at 60 MHz, Other peripherals include two UARTs, SPI and l2C interfaces, 6-channel PWM and 32-bit digital I/O port. All of which are fitted in a small 48-pin LQFP package!
Reprinted Url Of This Article: http://www.seekic.com/blog/project_solutions/2011/08/16/LPC210x_'ARMEE'_DEVELOPMENT_BOARD__Part_1__an_ARM_processor_survey_(1).html
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