The HAL Port

Name

HAL Port -- Implementation Details

Overview

This documentation explains how the eCos HAL specification has been mapped onto the phyCORE LPC2294 Board hardware, and should be read in conjunction with that specification. The phyCORE LPC229x platform HAL package complements the ARM architectural HAL and the LPC2xxx variant HAL. It provides functionality which is specific to the target board.

Startup

Following a hard or soft reset the HAL will initialize or reinitialize many of the on-chip peripherals. This includes the PINSEL functions and LED bank. There is an exception for RAM startup applications which depend on a ROM monitor for certain services.

For ROM startup, the HAL will perform additional initialization, programming the various internal registers including PLL (for the clocks); Memory Mapping control registers to map SRAM to 0x0; the memory controller for access to external FLASH, SRAM and ethernet; and the Memory Acceleration Module (MAM). The details of the early hardware startup may be found in the header cyg/hal/hal_platform_setup.h.

Linker Scripts and Memory Maps

The platform HAL package provides the memory layout information needed to generate the linker script. The key memory locations are as follows:

on-chip Flash

This is located at address 0x0 of the memory space, although after hardware initialization, the start of internal SRAM is mapped over locations 0x0 to 0x40. This region ends at 0x40000. The MAM is enabled to accelerate memory reads from this area. A driver is available for using this flash via the eCos flash API.

external Flash

This is located at address 0x80000000 of the memory space. It is not used by default by eCos, although if RedBoot is asked to manage the Flash, it reserves flash addresses 0x801E0000 thru 0x801FF000. If RedBoot stores its configuration data in Flash, then addresses 0x801FF000 thru 0x801FFFFF are reserved by RedBoot. RedBoot also reserves the first block of Flash at 0x80000000 thru 0x80001FFFF to ensure that it remains erased and does not therefore inhibit the execution of RedBoot from the internal Flash. External flash is 32bits wide and accessed with 7 wait states.

internal SRAM

This is located at address 0x40000000 of the memory space, ending at location 0x40004000. The first 64 bytes are mapped to location 0x0000000.

external SRAM

This is located at address 0x81000000 of the memory space, ending at location 0x81100000. For RAM startup, available SRAM starts at location 0x81010000, with the bottom 64Kbytes reserved for use by RedBoot.

on-chip peripherals

These are accessible via location 0xE0000000 onwards. Descriptions of the contents can be found in the LPC2294 User Manual.

Other Issues

The LEDs may be accessed from C with the following function:

#include <cyg/infra/hal_diag.h>
extern void hal_diag_led(int leds);
Values from 0 to 16 will be displayed on the LED bank representing the binary value with 1 being on and 0 being off, and with P0.7 being the MSB, and P0.4 the LSB.

The LEDs are also used during platform initialization and only P0.4 should be illuminated if booting has been successful. Other LED indications represent the stage in the initialization process that failed.

2017-02-09
Documentation license for this page: eCosPro License