Visible to Intel only — GUID: iga1401394827923
Ixiasoft
Visible to Intel only — GUID: iga1401394827923
Ixiasoft
28.2. Functional Description
Each PIO core can provide up to 32 I/O ports. An intelligent host such as a microprocessor controls the PIO ports by reading and writing the register-mapped Avalon® -MM interface. Under control of the host, the PIO core captures data on its inputs and drives data to its outputs. When the PIO ports are connected directly to I/O pins, the host can tristate the pins by writing control registers in the PIO core. The example below shows a processor-based system that uses multiple PIO cores to drive LEDs, capture edges from on-chip reset-request control logic, and control an off-chip LCD display.
When integrated into an Platform Designer-generated system, the PIO core has two user-visible features:
- A memory-mapped register space with four registers: data, direction, interruptmask, and edgecapture
- 1 to 32 I/O ports
The I/O ports can be connected to logic inside the FPGA, or to device pins that connect to off-chip devices. The registers provide an interface to the I/O ports via the Avalon® -MM interface. See Register Map for the PIO Core table for a description of the registers.