Processors ready for connectivity - Embedded.com

Processors ready for connectivity

National Semiconductor has developed a family of connectivityprocessors which combine embedded cores, analog functions, andsoftware and which are supported by a range of development platforms.

The Device Connectivity Division has been established to developconnectivity processor systems by leveraging the company's existingtechnology, products, processes, manufacturing and channels.

The CP3000 family initially consist of four devices and includes avariety of peripherals with two having Bluetooth baseband processingcapabilities. A Compact RISC core is combined with on-chip SRAM andFlash memory. The devices are based on National's CR16C architectureand the LMX5250 Bluetooth radio interface.

All devices have a number of on-chip communications peripheralsincluding MICROWIRE/PLUS, SPI, UART, ACCESS.bus, and an AdvancedAudio Interface (AAI). Additional on-chip peripherals include DMAcontroller, PCM/CSVD conversion module, timing and watchdog unit,versatile timer unit, multi-function timer, and multi-inputwakeup.

The CP3BT10 and CP3BT13 both have a Bluetooth lower linkcontroller (LCC) with the BT10 also having a USB peripheral while theBT13 has a CAN interface. The LLC has a shared 4.5Kbyte Bluetooth RAMand 1Kbyte Bluetooth sequencer RAM. The full-speed USB node includesseven endpoint-FIFOs conforming to USB 1.1 specification. The CANinterface with 15 message buffers conforms to CAN specification 2.0Bactive.

The CP3CN17 and CP3UB17 do not have the Bluetooth controller – theCN17 is CAN-enabled and the UB17 is USB-enabled.

All the devices have a fully static RISC processor core, capableof operating from 0 to 24MHz with zero wait/hold states. There is aminimum 41.2ns instruction cycle time with a 24MHz internal clockfrequency, based on a 12MHz external input. There are 30independently vectored peripheral interrupts.

On-chip memory includes 256Kbytes reprogrammable Flash programmemory, 8K bytes Flash data memory, 10K bytes of static RAM datamemory, addresses up to 8Mbytes of external memory.

The AAI is used to connect to external 8/13bit PCM Codecs as wellas to ISDN-controllers through the IOM-2 interface (slave only). ThePCM/CVSD converter supports one bidirectional audio connection.

The flexible I/O provides up to 37 general-purpose I/O pins(shared with on-chip peripheral I/O pins), programmable I/O pincharacteristics: TRI-STATE output, push-pull output, weak pull-upinput, high-impedance input, and there are Schmitt triggers on thegeneral purpose inputs. The power and clock management supportincludes on-chip Phase Locked Loop, support for multiple clockoptions, dual clock and reset, power-down modes. The power supply isI/O port operation at 2.5V to 3.3V, core logic operation at 2.5V andon-chip power-on reset.

The Bluetooth protocol stack enables applications to interface tothe high level protocols or directly to the low level host controllerinterface (HCI) while the transport layer support allows HCIcommand-based interface over UART or USB port. The baseband (linkcontroller) minimizes the performance demand on the CPU. All packettypes, piconet, and scatternet are functionality supported.

Application software resides on top of the Bluetooth protocolstack and accesses services by calling the Bluetooth library throughthe Application Programming Interface (API).

The stack consists of the low-level host controller core and thehigh-level host core. Most applications only call the highlevelservices provided by the host core. Applications which deal directlywith low level functions (such as existing applications ported fromother platforms) can bypass the upper layers of the stack and sendcommands directly to the standard HCI.

The µC/OS-II real-time kernel is a portable, ROMable,scalable, preemptive realtime, multitasking kernel that provides anumber of services including semaphores, event f lags, mutualexclusion semaphores (to reduce priority inversions), messagemailboxes, message queues, task management (Create, delete, changepriority, suspend/resume etc.), fixed-sized memory block managementand time management. The execution time for most of the servicesprovided by the µC/OS-II kernel is both constant anddeterministic. This means that execution times do not depend on thenumber of tasks running in the application. The µC/OS-II kernelis open-source software written in C.

The development environment includes pre-integrated hardware andsoftware support. There is a multi-file C source editor, high-level Csource debugger. Products include the IAR Embedded Workbench, iSYSTEMwinIDEA and iC3000 Active Emulator, Bluetooth development board andprotocol stack, and application software.

Published in Embedded Systems (Europe) November2002

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