■ DESCRIPTION

The MB91101 and MB91101A are a standard single-chip microcontroller constructed around the 32-bit RISC CPU (FR* family) core with abundant I/O resources and bus control functions optimized for high-performance/high-speed CPU processing for embedded controller applications. To support the vast memory space accessed by the 32-bit CPU, the MB91101 and MB91101A normally operate in the external bus access mode and executes instructions on the internal 1 Kbyte cache memory and 2 Kbytes RAM for enhanced performance.

The MB91101 and MB91101A are optimized for applications requiring high-performance CPU processing such as navigation systems, high-performance FAXs and printer controllers.

■ FEATURES

FR CPU

• 32-bit RISC, load/store architecture, 5-stage pipeline

• Operating clock frequency: Internal 50 MHz/external 25 MHz

(PLL used at source oscillation 12.5 MHz)

• General purpose registers: 32 bits × 16

• 16-bit fixed length instructions (basic instructions), 1 instruction/1 cycle

• Memory to memory transfer, bit processing, barrel shifter processing:

Optimized for embedded applications

• Function entrance/exit instructions, multiple load/store instructions of

register contents, instruction systems supporting high level languages

• Register interlock functions, efficient assembly language coding

• Branch instructions with delay slots: Reduced overhead time in branch executions

• Internal multiplier/supported at instruction level

Signed 32-bit multiplication: 5 cycles

Signed 16-bit multiplication: 3 cycles

• Interrupt (push PC and PS): 6 cycles, 16 priority levels

External bus interface

• Clock doubler: Internal 50 MHz, external bus 25 MHz operation

• 25-bit address bus (32 Mbytes memory space)

• 8/16-bit data bus

• Basic external bus cycle: 2 clock cycles

• Chip select outputs for setting down to a minimum memory block size of 64 Kbytes: 6

• Interface supported for various memory technologies

DRAM interface (area 4 and 5)

• Automatic wait cycle insertion: Flexible setting, from 0 to 7 for each area

• Unused data/address pins can be configured as input/output ports.

• Little endian mode supported (Select 1 area from area 1 to 5)

DRAM interface

• 2 banks independent control (area 4 and 5)

• Normal mode (double CAS DRAM)/high-speed page mode (single CAS DRAM)/Hyper DRAM

• Basic bus cycle: Normally 5 cycles, 2-cycle access possible in high-speed page mode

• Programmable waveform: Automatic 1-cycle wait insertion to RAS and CAS cycles

• DRAM refresh

CBR refresh (interval time configurable by 6-bit timer)

Self-refresh mode

• Supports 8/9/10/12-bit column address width

• 2CAS/1WE, 2WE/1CAS selective

Cache memory

• 1-Kbyte instruction cache memory

• 32 block/way, 4 entry(4 word)/block

• 2 way set associative

• Lock function: For specific program code to be resident in cashe memory

DMA controller (DMAC)

• 8 channels

• Transfer incident/external pins/internal resource interrupt requests

• Transfer sequence: Step transfer/block transfer/burst transfer/continuous transfer

• Transfer data length: 8 bits/16 bits/32 bits selective

• NMI/interrupt request enables temporary stop operation.

UART

• 3 independent channels

• Full-duplex double buffer

• Data length: 7 bits to 9 bits (non-parity), 6 bits to 8 bits (parity)

• Asynchronous (start-stop system), CLK-synchronized communication selective

• Multi-processor mode

• Internal 16-bit timer (U-TIMER) operating as a proprietary baud rate generator: Generates any given baud rate

• External clock can be used as a transfer clock.

• Error detection: Parity, frame, overrun

(Continued)