— eCos Support for the NXP PNX8330 Processor
The NXP PNX8330 processor is based around a 4KEc MIPS32 core,
complemented by a range of on-chip peripherals. The HAL package
CYGPKG_HAL_MIPS_PNX8330 provides the
It complements the MIPS architectural
CYGPKG_HAL_MIPS, the MIPS32 variant
CYGPKG_HAL_MIPS_MIPS32 and the PNX83xx
contains support for features common to several members of the PNX83xx
family. An eCos configuration should also include a platform HAL
support board-level details like the memory chips and off-chip
The PNX8330 HAL package should be loaded automatically when eCos is configured for appropriate target hardware. It should never be necessary to load this package explicitly. Unloading the package should only happen as a side effect of switching target hardware. The package does not contain any user-settable options.
The HAL Port
This section describes how the PNX8330 HAL package implements parts of the eCos HAL specification. It should be read in conjunction with similar sections from the architectural and variant HAL documentation.
The header file
definitions of the on-chip peripherals used by eCos, except for some
UART definitions which are provided by the PNX83xx support HAL
instead. This header file is automatically included by the
cyg/hal/hal_io.h, so typically
application code and other packages will just include the latter. The
register addresses are all in kseg1 so will be accessed uncached.
The header file
cyg/hal/pnx8330_intr.h provides ISR vector
numbers for all interrupt sources, for example
CYGNUM_HAL_ISR_PIO_1. These vector numbers should
be used for calls like
header file is automatically included by the architectural header
cyg/hal/hal_intr.h, and other
packages and application code will normally just include the latter.
The interrupt vectors come in four groups. There are six vectors
corresponding to the external interrupts available in the CPU SR and
CAUSE registers. Of these, interrupt number 2 is attached to the
on-chip interrupt controller, and interrupt number 5 is attached to
the internal COMPARE register, which is used to supply system time
interrupts. There are 37 vectors for the on-chip peripherals,
managed by the priority interrupt controller. One of these,
CYGNUM_HAL_ISR_PIO is reserved for use by the HAL's
interrupt decoding code to detect PIO interrupts and decode them
into the next 16 vectors. Another peripheral interrupt,
CYGNUM_HAL_ISR_CONFIG is decoded into the final seven
interrupt vectors, which correspond to the interrupt sources available
from the CONFIG unit.
The eCos HAL macros
HAL_INTERRUPT_SET_LEVEL are implemented by the
processor HAL. The implementations depend on the interrupt vector.
HAL_INTERRUPT_ACKNOWLEDGE is only needed for PIO
and CONFIG interrupts, otherwise it is a no-op.
HAL_INTERRUPT_CONFIGURE is only relevant for PIO
Interrupt priorities should be in the range 1 to 14, and correspond to
int_priority fields in the
pic_int_reg registers. 1 is the lowest
priority and 14 the highest. Interrupt priorities are ignored for the
COMPARE interrupt. All PIO and CONFIG interrupt sources operate at the
same priority, which is the highest priority assigned to any of the
PIO or CONFIG vectors.
Interrupt chaining via the common HAL's configuration option
CYGIMP_HAL_COMMON_INTERRUPTS_CHAIN is supported for
PIO interrupts only. This makes it possible to connect several
external peripherals' interrupt lines to a single PIO pin if desired.
The 4kEc core provides standard COUNTER and COMPARE registers which are used for the eCos system clock. The CONFIG unit timer 0 is used for gprof-based profiling if enabled, otherwise it can be used by the application. The CONFIG unit watchdog timer is supported by a watchdog driver.
The PNX8330 has an 8K data cache and a 16k instruction cache, which
are automatically initialized and enabled by the eCos startup
code. All the standard cache control macros are supported through the
cache instruction. However, since all memory is
always available both cached and uncached as part of the architecture,
these are not always necessary.
The PNX8330 HAL provides a profiling timer for use with the gprof
profiling package. This uses the PNX8330 configuration timer 0, so
application code should not manipulate this timer if profiling is
enabled. The MIPS architectural HAL implements the
mcount function so profiling is fully supported
on all PNX8330-based platforms.
HAL_PLATFORM_RESET is implemented via the
PNX8330's system reset unit, and involves a full reset of the core and
all peripherals. Hence, whenever a soft reset is performed by the
application or via a gdb command, the system should start up again in a
clean state, and there is no need for the system to reinitialize all
The PNX8330 HAL does not affect the implementation of data types, stack size definitions, bit indexing, idle thread processing, SMP support, system startup, or debug support.
The PNX8330 processor HAL only implements functionality defined in the eCos HAL specification and does not export any additional functions.
|2022-03-29||eCosPro Non-Commercial Public License|