20 June 2008

Atmel – First ARM7 Based MCU With Direct FPGA Interface

Atmel Corporation has rolled out the AT91CAP7E, claimed to the industry's first ARM7-based MCU with a direct FPGA interface.

The AT91CAP7E is a standard microcontroller with an FPGA interface that makes the FPGA look and work like it is on the internal bus of the MCU. It provides customers with a two-chip, no-NRE, FPGA-plus ARM7 solution and offers an engineering-free migration path to a lower cost, and a lower power customizable MCU, Atmel explained.

The CAP7E includes a six-layer advanced high-speed bus (AHB), peripheral DMA controller and 160 Kbytes of on-chip SRAM. On chip peripherals include USB 2.0 full speed device, SPI master and slave, two USARTs, three 16-bit timer counters, an 8-channel/ 10-bit analog to digital converter, plus a full-functioned system controller including interrupt and power control and supervisory functions. The FPGA interface on the CAP7E provides the FPGA with direct access to the CAP7E's on-chip AHB and peripheral DMA controller. This architecture eliminates FPGA-induced bus contention, off-loads MCU-to-FPGA communications from the CPU, and frees up the external bus interface for external memory access.

Interfacing an ARM7-based MCU to an FPGA has traditionally been done through the external bus interface (EBI) or programmable I/O. Either arrangement requires that the CPU transfer data to and from the FPGA one word-at-a-time. The FPGA interface on Atmel's CAP7E provides the FPGA with two AHB masters, four AHB slaves, a special direct AHB slave interface to an external RAM through the FPGA, and a programmable ROM that remaps the external RAM to emulate and debug the ROM code. Fourteen advanced peripheral bus (APB) slaves, two full-duplex DMA channels and 32-bit programmable I/O may be hardware selected to share I/O. An on-chip priority interrupt controller provides up to 13 encoded interrupts and two additional un-encoded interrupts for DMA transfers.

The same C-compilers, RTOS, ICEs and IDEs used with Atmel's AT91SAM ARM-based MCUs can be used with CAP. Atmel's AT91CAP7E is available immediately, the company confirmed.