The RM48Lx40 device is a high-performance microcontroller family for
safety systems. The safety architecture includes dual CPUs in lockstep, CPU
and memory BIST logic, ECC on both the flash and the data SRAM, parity on
peripheral memories, and loopback capability on peripheral I/Os.
The RM48Lx40 device integrates the ARM Cortex-R4F Floating-Point
CPU. The CPU offers an efficient 1.66 DMIPS/MHz, and has configurations that
can run up to 200 MHz, providing up to 332 DMIPS. The device supports the
little-endian [LE] format.
The RM48L940 device has 3MB of integrated flash and 256KB of data RAM. The
RM48L740 device has 2MB of integrated flash and 256KB of data RAM. The RM48L540
device has 2MB of integrated flash and 192KB of data RAM. Both the flash and
RAM have single-bit error correction and double-bit error detection. The
flash memory on this device is a nonvolatile, electrically erasable, and
programmable memory implemented with a 64-bit-wide data bus interface. The
flash operates on a 3.3-V supply input (same level as I/O supply) for all
read, program, and erase operations. When in pipeline mode, the flash operates
with a system clock frequency of up to 200 MHz. The SRAM supports
single-cycle read and write accesses in byte, halfword, word, and double-word
The RM48Lx40 device features peripherals for real-time control-based
applications, including two Next Generation High-End Timer (N2HET) timing
coprocessors and two 12-bit Analog-to-Digital Converters (ADCs) supporting up
to 24 inputs.
The N2HET is an advanced intelligent timer that provides sophisticated timing
functions for real-time applications. The timer is software-controlled, using
a reduced instruction set, with a specialized timer micromachine and an
attached I/O port. The N2HET can be used for pulse-width-modulated outputs,
capture or compare inputs, or GPIO. The N2HET is especially well suited for
applications requiring multiple sensor information and drive actuators with
complex and accurate time pulses. A High-End Timer Transfer Unit (HTU) can
perform DMA-type transactions to transfer N2HET data to or from main memory.
A Memory Protection Unit (MPU) is built into the HTU.
The device has two 12-bit-resolution MibADCs with 24 channels and 64 words
of parity-protected buffer RAM each. The MibADC channels can be converted
individually or can be grouped by software for sequential conversion
sequences. Sixteen channels are shared between the two MibADCs. There are
three separate groupings. Each sequence can be converted once when triggered or
configured for continuous conversion mode. The MibADC has a 10-bit mode for
use when compatibility with older devices or faster conversion time is
The device has multiple communication interfaces: three MibSPIs, two
SPIs, one LIN, one SCI, three DCANs, one I2C module, and one Ethernet. The
SPIs provide a convenient method of serial high-speed communication between
similar shift-register type devices. The LIN supports the Local Interconnect
standard 2.0 and can be used as a UART in full-duplex mode using the standard
Non-Return-to-Zero (NRZ) format.
The DCAN supports the CAN 2.0 (A and B) protocol standard and uses a
serial, multimaster communication protocol that efficiently supports
distributed real-time control with robust communication rates of up to 1
Mbps. The DCAN is ideal for systems operating in noisy and harsh environments
(for example, automotive vehicle networking and industrial fieldbus) that
require reliable serial communication or multiplexed wiring.
The Ethernet module supports MII, RMII, and MDIO interfaces.
The I2C module is a multimaster communication module providing an
interface between the microcontroller and an I2C-compatible device
through the I2C serial bus. The I2C supports speeds of
100 and 400 Kbps.
The Frequency-Modulated Phase-Locked Loop (FMPLL) clock module is used to
multiply the external frequency reference to a higher frequency for internal
use. There are two FMPLL modules on this device. These modules, when enabled,
provide two of the seven possible clock source inputs to the Global Clock
Module (GCM). The GCM manages the mapping between the available clock sources
and the device clock domains.
The device also has an External Clock Prescaler (ECP) module that when
enabled, outputs a continuous external clock on the ECLK pin (or ball). The
ECLK frequency is a user-programmable ratio of the peripheral interface clock
(VCLK) frequency. This low-frequency output can be monitored externally as an
indicator of the device operating frequency.
The DMA controller has 16 channels, 32 peripheral requests, and parity
protection on its memory. An MPU is built into the DMA to limit the DMA to
prescribed areas of memory and to protect the rest of the memory system from
any malfunction of the DMA.
The Error Signaling Module (ESM) monitors all device errors and determines
whether an interrupt is generated or the external ERROR
pin is toggled when a fault is detected. The ERROR
pin can be monitored externally as an indicator of a fault condition in the
The External Memory Interface (EMIF) provides off-chip expansion
capability with the ability to interface to synchronous DRAM (SDRAM) devices,
asynchronous memories, peripherals, or FPGA devices.
Several interfaces are implemented to enhance the debugging capabilities
of application code. In addition to the built-in ARM Cortex-R4F CoreSight
debug features, an External Trace Macrocell (ETM) provides instruction and
data trace of program execution. For instrumentation purposes, a RAM Trace Port
(RTP) module is implemented to support high-speed tracing of RAM and
peripheral accesses by the CPU or any other master. A Data Modification
Module (DMM) gives the ability to write external data into the device memory.
Both the RTP and DMM have no or only minimum impact on the program execution
time of the application code. A Parameter Overlay Module (POM) can reroute flash
accesses to internal memory or to the EMIF. This rerouting allows the dynamic
calibration against production code of parameters and tables without
rebuilding the code to explicitly access RAM or halting the processor to
reprogram the data flash.
With integrated safety features and a wide choice of communication and
control peripherals, the RM48Lx40 device is an ideal solution for
high-performance real-time control applications with safety-critical