Infobox BSP

BSP_name Steroid Stomp 555, ss555
Manufacturer Intec Automation Inc
image Ss555_69px.jpg
caption N/A
Architecture PowerPC
CPU_model Freescale PowerPC MPC555 (Black Oak)
Monitor BDM
Video None.
Aliases brs5l
RAM 512k 2-1-1-1 burst SRAM
NVMEM Flash cartridges ranges from 64 Mbit up to 8 Gbit (Commercial carts range from 32 Mbit to 256 Mbit).
Serial 2 SCI
Other 32 analog inputs with 10 bit resolution, highly programmable

from README,v 1.1 2004/04/12 21:52:13 joel Exp edited by dave erickson

This is a README file for the Intec SS555 of RTEMS 4.6.0

The SS555 port was sponsored by Defence Research and Development Canada - Suffield, and is Copyright (C) 2004, Real-Time Systems Inc.

Please send any comments, improvements, or bug reports to:

David Querbach querbach@…


BSP NAME: ss555 BOARD: Intec Automation Inc. SS555 BUS: None CPU FAMILY: PowerPC CPU: Freescale PowerPC MPC555 (Black Oak) COPROCESSORS: Built-in Motorola TPU3 * 2 MODE: 32 bit mode Little Endian or Big Endian DEBUG MONITOR: BDM


TIMERS: PIT / Timebase RESOLUTION: 1 microsecond (4 MHz crystal / 4) SERIAL PORTS: 2 SCI REAL-TIME CLOCK: On-chip. DMA: None. VIDEO: None. SCSI: None. NETWORKING: None.



On-chip resources

SCI1 serial port SCI2 serial port (console) PIT clock TB timing test support DEC SWT watchdog timer -- enable in startup/iss555.c *CS0 external 512k 2-1-1-1 Burst SRAM *CS1 *CS2 *CS3 CPLD IRQ0 IRQ1 IRQ2 IRQ3 IRQ4 IRQ5 IRQ6 IRQ7 IRQ_LVL0 IRQ_LVL1 IRQ_LVL2 IRQ_LVL3 IRQ_LVL4 IRQ_LVL5 SCI IRQ_LVL6 PIT IRQ_LVL7

Board description

Clock rate: 40 MHz development/embeddable board Bus width: 32-bit on-board RAM, 16-bit off-board I/O FLASH: 512k on-chip RAM: 512k 2-1-1-1 burst SRAM


The ss555 port uses the Intec SS555's external RAM in two different ways, depending on whether or not it is built for debugging by giving the VARIANT=DEBUG switch to make:


  1. In the debugging case, the linker script concanttenates the .text,

.data, and .bss sections starting at location zero, so they all can be loaded into the external RAM for debugging. We assume that the debugger disables the internal Flash ROM and enables the external RAM before loading the code into the external RAM.

  1. In the normal (non-debugging) case, the linker script still places the

.text section near zero, but places the start of the .data and .bss sections at the start location of the MPC555's internal RAM. The system startup code then configures the external RAM just after the internal RAM in memory, forming one large block from the two RAM devices.

Console driver

This BSP includes an termios-capable asynchronous serial line driver that supports SCI1 and SCI2. The RTEMS console is selected at configuration time with the CONSOLE_MINOR variable (see .../ss555/ We default to SCI2 for the console, since SCI1 has some extra features which may be desired for application use.

The BSP console supports three different modes of operation:

  1. polled I/O done with termios support,
  2. polled I/O done without termios support,
  3. interrupt-driven I/O with termios support.

The mode of operation of the serial driver is determined at configure time in part by the value of the UARTS_IO_MODE variable (see .../ss555/

0 - polled I/O. 1 - interrupt-driven I/O.

Also, set the value of UARTS_USE_TERMIOS to select whether termios should be used to perform buffering and input/output processing. Without termios support, input processing is limited to the substitution of LF for a received CR, and output processing is limited to the transmission of a CR following the transmission of a LF. The choices for UARTS_USE_TERMIOS are:

0 - do not use termios 1 - use termios

In most real-time applications, the driver should be configured to use termios and interrupt-driven I/O. Special requirements may dictate otherwise.

Polled I/O must be used when running the timing tests. It must also be used to run some other tests and some samples, such as the cdtest. Some tests change the interrupt mask and will hang interrupt-driven I/O indefinitely. Others, such as cdtest, perform console output from the static constructors before the console is opened, causing the test to hang. Still other tests produce output that is supposed to be in some specific order. For these tests, termios should not be used, as termios buffers output and the transmission of the buffers occur at somewhat unpredictable times.

The real solution is to fix the tests so that they work with interrupt-driven I/O and termios.

printk() and debug output

The implementation of printk() in RTEMS is mostly independent of most system services. The printk() function can therefore be used to print messages to a debug console, particularly when debugging startup code or device drivers, i.e. code that runs before the console driver is opened or that runs with interrupts disabled.

Support is provided to send printk output to either port. Specify the desired port at configure time by setting the value of PRINTK_MINOR to one of SCI1_MINOR or SCI2_MINOR.

printk() always uses polled I/O, and never uses termios.

If the printk() port is opened by RTEMS, then UARTS_IO_MODE must be set for polled I/O, otherwise the I/O functions will be in conflict. Using printk() before the port is initialized is, of course, not possible. This initialization occurs in console_initialize(), which is called by rtems_initialize_executive_early().

Watchdog Timer

The MPC555 watchdog timer can be enabled at configuration time by defining the WATCHDOG_TIMEOUT variable. This variable sets the watchdog timeout period in steps of

2048/Fsystem = 2048/40 MHz = 51.2 usec

or about 1/20 msec. When WATCHDOG_TIMEOUT is left undefined, the watchdog timer is disabled.


Most code came from the mbx8xx port, except for the floating-point handling which came from the mpc8260ads.

Host System

The port was developed on an x86 box running Debian 3.0. The toolchain was built from the sources at, except for the autotools which came from the Debian distribution.

Test Configuration

Board: Intec SS555 v1.1 CPU: Motorola MPC555LFMZP40, mask 1K83H Clock Speed: Crystal 4.0 MHz, CPU 40.0 MHz RAM: 512K bytes of 2-1-1-1 Burst SRAM Times Reported in: Microseconds Timer Source: Timebase clock GCC Flags: -O4 -fno-keep-inline-functions -mcpu=(821/860) Console: Operates in polled mode on SMC2. No I/O through EPPC-Bug.

Test Results

Single processor tests:

All tests passed, except that:

  • sp09 aborts due to memory shortage
  • sp20 needs to be run with output buffering enabled (see buffer_test_io.h)

Multi-processor tests:

Not applicable.

Library tests:

All tests passed. Note that the termios test only works if the system is rebuilt with termios enabled.

Posix tests:

All tests passed, except that:

  • the message queue test failed with "errno (91 - File or path name too long)"

Timing tests:

Due to memory limitations, many of the tests will not run unless you set OPERATION_COUNT=20 at configuration time.

To run tm27 (the interrupt latency timer test), short CN5-48 to CN5-50 on the SS555 board.

All tests run cleanly, except for tm26, which gives a "PANIC 12" after it exits. This doesn't seem to cause a problem otherwise.

See the times file for the results of the timing tests.

Network tests:

Not applicable.

Sample programs:

These run correctly, except that:

  • The "minimum" sample is not designed to run properly on any system.
  • The loopback, fileio, unilimited, and pppd tests fail due to memory limitations.
  • The paranoia program dies on a floating-point assist exception.
Last modified on Nov 8, 2018 at 5:11:32 PM Last modified on Nov 8, 2018, 5:11:32 PM