External I/O Control-Using the GPIO Unit to Control the

External I/O Devices

Speaker: Yu-Ju Cho 卓余儒Advisor: Prof. An-Yeu Wu 吳安宇教授National Taiwan UniversityAdopted from Chang Gung University

Goal of This Lab Understand the operation mechanism of a

GPIO (General Purpose Input/Output) unit Design a GPIO and verify the design on the

Logic Module Learn the method of connecting an external

I/O device to the ARM Integrator Platform Employ the GPIO to control the external I/O

device.

ARM PrimeCell GPIO General Purpose Input/Output (GPIO) The GPIO is an AMBA slave module that connects

to the APB. Which has 16 pins organized into two 8-bit ports.

The block diagram of GPIO

Functional Overview The data direction register is 8 bits wide, and

is programmed to select whether each individual input/output pin is configured as an input or an output.

The data register is 8 bits wide, and is used to read the value input on those pins are configured as input, and program the value output on the output pins.

Data Direction Register GPIOPADDR is the port A data direction

register. Bits set in GPIOPADDR will set the corresponding

pin in PORT A to be an output. Clearing a bit configures the pin to be an input.

GPIOPBDDR is the port B data direction register. Bits cleared in GPIOPBDDR will set the

corresponding pin in PORT B to be an output. Setting a bit configures the pin to be an input

AMBA APB interface The AMBA APB group narrow-bus peripherals to

avoid loading the system bus, and provides an interface using memory-mapped registers.

Memory Address The base address of the PrimeCell

GPIO is not fixed, and may be different for any particular system. But the offset of any particular register is fixed

Programmer’s model

GPIO Operation Write Operation

Setup CycleENABLE Cycle

GPIO Operation (cont.) Read Operation

Setup CycleENABLE Cycle

Connect an external device to the ARM Integrator

Remember to series resistances

The Prototyping Grids on LM

Pin Names of FPGA

Pin Assignment for Port A NET GPIO1XPA<0> LOC=b20; NET GPIO1XPA<1> LOC=a21; NET GPIO1XPA<2> LOC=b21; NET GPIO1XPA<3> LOC=a22; NET GPIO1XPA<4> LOC=b22; NET GPIO1XPA<5> LOC=c22; NET GPIO1XPA<6> LOC=d22; NET GPIO1XPA<7> LOC=e22;

Pin Assignment for Port B NET GPIO1XPB<0> LOC=a23; NET GPIO1XPB<1> LOC=b23; NET GPIO1XPB<2> LOC=c23; NET GPIO1XPB<3> LOC=d23; NET GPIO1XPB<4> LOC=e23; NET GPIO1XPB<5> LOC=a24; NET GPIO1XPB<6> LOC=b24; NET GPIO1XPB<7> LOC=c24;

References ARM PrimeCell General Purpose Input/Output (PL0

60) Technical Reference Manual (ARM DDI 0142B).

Zong-xin Lin, “Design of an ARM-based System-on-Chip for Real-time QRS Detection in Electrocardiogram,” master thesis, Department of Electrical Engineering, Chang Gung University, Taiwan, June 2003.

Xilinx Logic Module Schematics:lm_xcv600e_revc.pdf