Here we are constructing a small peripheral which has a 1 bit register. This one bit register is actually indicating the status of the LED. If status is 1 which means LED is glowing and 0 means LED id off. Writing to this bit it will alter the state as per provided. We have "Mini2440 Hardware Essentials" data sheet of mini2440 board and we need pin details of -

  1. System clock pin (hclk)
  2. Address/Chip Select of peripheral
  3. Data Bit 0 pin
  4. Read Enable Pin
  5. Write Enable Pin
  6. Wait Pin
  7. Interrupt Pin
Following section contains descriptions of pin details found in MINI2440 board specification.

MINI2440 FPGA interfacing

GPIO - Mini2440 with a 34 Pin 2.0mm pitch GPIO interface on CON4. CON4 contains the GPIO pins and a number of other CPU-pins, such as AIN0-AIN3, CLKOUT, SPI interface, I2C interface, GPB0 and GPB1.

MINI2440 Board GPIO

System Interface Expansion Bus - The CON5 interface expansion contains a total of 16 data lines (D0-D15), 8 Address Lines (A0-A6, A24) and some control signal lines (chip select, read and write, reset, etc.). CON5 can supply 5V directly from one of the power supply input pins.

MINI2440 Board CON5

We selected these pins for our experiment.

  • 33 - CLKOUT0 (GPH9)
  • 8 - nGCS2 CS2 GPA13 (addr 0x10000000)
  • 25 - LDATAT0 data 0 bit
  • 11 - LnOE read enable
  • 12 - LnWE write enable
  • 13 - nWAIT
  • 5 - EINT3
Kindly note - generally H/W vendors should connect all 32 bit address and 16/32bit data pins to the target and should handle the logic. Here we are using only one Address select(CS) and one data bit for simplifying our understanding.