libdragon
Modules | Files | Data Structures | Macros | Functions
Low Level Hardware Interfaces

Low level hardware interface descriptions and functionality. More...

Modules

 DMA Controller
 DMA functionality for transfers between cartridge space and RDRAM.
 
 Exception Handler
 Handle hardware-generated exceptions.
 
 Interrupt Controller
 N64 interrupt registering and servicing routines.
 
 Joybus Subsystem
 Joybus peripheral interface.
 
 N64 System Interface
 N64 bootup and cache interfaces.
 
 RSP interface
 RSP basic library and command queue.
 

Files

file  joybus.c
 Joybus Subsystem.
 
file  joybus.h
 Joybus Subsystem.
 
file  regsinternal.h
 Register definitions for various hardware in the N64.
 

Data Structures

struct  AI_regs_t
 Register definition for the AI interface. More...
 
struct  MI_regs_t
 Register definition for the MI interface. More...
 
struct  VI_regs_t
 Register definition for the VI interface. More...
 
struct  PI_regs_t
 Register definition for the PI interface. More...
 
struct  SI_regs_t
 Register definition for the SI interface. More...
 
struct  SP_regs_t
 Register definition for the SP interface. More...
 

Macros

#define JOYBUS_BLOCK_SIZE   64
 Size of a Joybus input/output block in bytes.
 
#define JOYBUS_BLOCK_DWORDS   ( JOYBUS_BLOCK_SIZE / sizeof(uint64_t) )
 Size of a Joybus input/output block in double-words.
 

Functions

void joybus_exec (const void *inblock, void *outblock)
 Write a 64-byte block of data to the PIF and read the 64-byte result. More...
 

Detailed Description

Low level hardware interface descriptions and functionality.

The low level hardware interfaces handle several functions in the N64 that would otherwise be handled by a kernel or RTOS. This includes the DMA Controller, the Exception Handler, the Interrupt Controller and the N64 System Interface. The DMA controller handles DMA requests between the cartridge and the N64 RDRAM. Other systems in the N64 have their own DMA controllers that are handled in the relevant subsystems. The exception handler traps any exceptions raised by the N64, including the reset exception. The interrupt handler sets up the MIPS interface (MI) which handles low level interrupt functionality for all other systems in the N64. The N64 system interface provides the ability for code to manipulate cache and boot options.


Data Structure Documentation

◆ AI_regs_t

struct AI_regs_t

Register definition for the AI interface.

Data Fields
volatile void * address Pointer to uncached memory buffer of samples to play.
uint32_t length Size in bytes of the buffer to be played. Should be number of stereo samples * 2 * sizeof( uint16_t )
uint32_t control DMA start register. Write a 1 to this register to start playing back an audio sample.
uint32_t status AI status register. Bit 31 is the full bit, bit 30 is the busy bit.
uint32_t dacrate Rate at which the buffer should be played.

Use the following formula to calculate the value: ((2 * clockrate / frequency) + 1) / 2 - 1

uint32_t samplesize The size of a single sample in bits.

◆ MI_regs_t

struct MI_regs_t

Register definition for the MI interface.

Data Fields
uint32_t mode Mode register.
uint32_t version Version register.
uint32_t intr Current interrupts on the system.
uint32_t mask Interrupt mask.

◆ VI_regs_t

struct VI_regs_t

Register definition for the VI interface.

Data Fields
uint32_t control VI control register. Sets up various rasterization modes.
void * framebuffer Pointer to uncached buffer in memory to rasterize.
uint32_t width Width of the buffer in pixels.
uint32_t v_int Vertical interrupt control register. Controls which horizontal line must be hit to generate a VI interrupt.
uint32_t cur_line Current vertical line counter.
uint32_t timing Timing generation register for PAL/NTSC signals.
uint32_t v_sync Number of lines per frame.
uint32_t h_sync Number of pixels in line and leap pattern.
uint32_t h_sync2 Number of pixels in line, set identically to h_sync.
uint32_t h_limits Beginning and end of video horizontally.
uint32_t v_limits Beginning and end of video vertically.
uint32_t color_burst Beginning and end of color burst in vertical lines.
uint32_t h_scale Horizontal scaling factor from buffer to screen.
uint32_t v_scale Vertical scaling factor from buffer to screen.

◆ PI_regs_t

struct PI_regs_t

Register definition for the PI interface.

Data Fields
volatile void * ram_address Uncached address in RAM where data should be found.
uint32_t pi_address Address of data on peripheral.
uint32_t read_length How much data to read from RAM into the peripheral.
uint32_t write_length How much data to write to RAM from the peripheral.
uint32_t status Status of the PI, including DMA busy.
uint32_t dom1_latency Cartridge domain 1 latency in RCP clock cycles. Requires DMA status bit guards to work reliably.
uint32_t dom1_pulse_width Cartridge domain 1 pulse width in RCP clock cycles. Requires DMA status bit guards to work reliably.

◆ SI_regs_t

struct SI_regs_t

Register definition for the SI interface.

Data Fields
volatile void * DRAM_addr Uncached address in RAM where data should be found.
volatile void * PIF_addr_read Address to read when copying from PIF RAM.
uint32_t reserved1 Reserved word.
uint32_t reserved2 Reserved word.
volatile void * PIF_addr_write Address to write when copying to PIF RAM.
uint32_t reserved3 Reserved word.
uint32_t status SI status, including DMA busy and IO busy.

◆ SP_regs_t

struct SP_regs_t

Register definition for the SP interface.

Data Fields
volatile void * RSP_addr RSP memory address (IMEM/DMEM)
volatile void * DRAM_addr RDRAM memory address.
uint32_t rsp_read_length RDRAM->RSP DMA length.
uint32_t rsp_write_length RDP->RDRAM DMA length.
uint32_t status RSP status.
uint32_t rsp_dma_full RSP DMA full.
uint32_t rsp_dma_busy RSP DMA busy.
uint32_t rsp_semaphore RSP Semaphore.

Function Documentation

◆ joybus_exec()

void joybus_exec ( const void *  input,
void *  output 
)

Write a 64-byte block of data to the PIF and read the 64-byte result.

This function is not a stable feature of the libdragon API and should be considered experimental!

The usage of this function will likely change as a result of the ongoing effort to integrate the multitasking kernel with asynchronous operations.

Parameters
[in]inputSource buffer for the input block to send to the PIF
[out]outputDestination buffer to place the output block from the PIF