Cyclone® V Hard Processor System Technical Reference Manual

ID 683126
Date 8/28/2023
Public
Document Table of Contents

4.1.3.1. Modules Requiring Software Deassert

The reset manager leaves the reset signal asserted on certain modules even after the rest of the HPS has come out of reset. These modules are likely to require software configuration before they can safely be taken out of reset.

When a module that has been held in reset is ready to start running, software can deassert the reset signal by writing to the appropriate register, shown in the following table.

Table 25.  Module Reset Signals and Registers
HPS Peripheral Reset Register Module Reset Signal Reset Group
MPU mpumodrst mpu_cpu_rst_n[1] MPU
Ethernet MAC permodrst emac_rst_n[1:0] PER
USB 2.0 OTG permodrst usb_rst_n[1:0] PER
NAND permodrst nand_flash_rst_n PER
Quad SPI permodrst qspi_flash_rst_n PER
Watchdog permodrst watchdog_rst_n[1:0] PER
Timer permodrst osc1_timer_rst_n[1:0] PER
Timer permodrst sp_timer_rst_n[1:0] PER
I2C permodrst i2c_rst_n[3:0] PER
UART permodrst uart_rst_n[1:0] PER
SPI Master permodrst spim_rst_n[1:0] PER
SPI Slave permodrst spis_rst_n[1:0] PER
SD/MMC permodrst sdmmc_rst_n PER
CAN permodrst can_rst_n[1:0] PER
GPIO permodrst gpio_rst_n[2:0] PER
DMA permodrst dma_rst_n PER
SDRAM permodrst sdram_rst_n PER
DMA Peripheral Interfaces per2modrst dma_periph_if_rst_n[7:0] PER2
HPS-to-FPGA Bridge brgmodrst hps2fpga_bridge_rst_n Bridge
FPGA-to-HPS Bridge brgmodrst fpga2hps_bridge_rst_n Bridge
Lightweight HPS-to-FPGA Bridge brgmodrst lwhps2fpga_bridge_rst_n Bridge