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 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.

AMBA APB interface The AMBA APB group narrow-bus peripherals to avoid loading the system bus, and provides an interface using memory-mapped registers.

Programmer’s model

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

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

GPIO Operation Write Operation

GPIO Operation (cont.) Read Operation

Connect an external device to the ARM Integrator

The Prototyping Grids on LM

Pin Names of FPGA

Pin Assignment for Port A GPIO1XPA[0] : LOCATION = Pin_Y24 GPIO1XPA[1] : LOCATION = Pin_AA24 GPIO1XPA[2] : LOCATION = Pin_AB24 GPIO1XPA[3] : LOCATION = Pin_Y23 GPIO1XPA[4] : LOCATION = Pin_AA23 GPIO1XPA[5] : LOCATION = Pin_AB23 GPIO1XPA[6] : LOCATION = Pin_AD23 GPIO1XPA[7] : LOCATION = Pin_AC22

Pin Assignment for Port B GPIO1XPB[0] : LOCATION = Pin_AD22 GPIO1XPB[1] : LOCATION = Pin_AC21 GPIO1XPB[2] : LOCATION = Pin_AD21 GPIO1XPB[3] : LOCATION = Pin_W20 GPIO1XPB[4] : LOCATION = Pin_Y20 GPIO1XPB[5] : LOCATION = Pin_AA20 GPIO1XPB[6] : LOCATION = Pin_AB20 GPIO1XPB[7] : LOCATION = Pin_AC20 GPIO1XPB[8] : LOCATION = Pin_AD20 GPIO1XPB[9] : LOCATION = Pin_Y19 CTRLCLK2[6] : LOCATION = Pin_K18

References ARM PrimeCell General Purpose Input/Output (PL060) 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.