User guide

32 GR-LEON4-ITX Development Board

Quick Start Guide

6 TROUBLESHOOTING AND FREQUENCY ASKED QUESTIONS

6.1 General

The performance of the system is less compared to what is advertised for LEON4

The advertised LEON4 performance figures typically come from systems that include a

Level-2 cache core. The GR-LEON4-ITX board and LEON4-ASIC-DEMO device were

constructed using a pre-release version of the LEON4 processor and the L2 cache core was

not available at this time. If you need to benchmark a system with a Level-2 cache, please

contact Aeroflex Gaisler.

I lost the contents of the USB Flash stick

Contact Aeroflex Gaisler for a possible download of the original stick contents, or a

replacement stick.

How do I restore the original PROM contents?

A copy of the original PROM contents is available in the GR-LEON4-ITX data package

under the directory gr-l4itx-pack/prom. The file l4itx_prom.srec can be written to the SPI boot

PROM using the GRMON commands: spim flash detect, spim flash erase, spim flash load

l4itx_prom.srec.

GRMON reports a system frequency of 100 MHz, should it not be 200 MHz?

The bus with most of the peripherals (AHB bus 1) runs at 100 MHz and the bus with the

LEON4 processors (AHB bus 0) runs at 200 MHz. GRMON connects bus 1 and also finds

the timer unit there, therefore GRMON reports the system frequency as 100 MHz, the

processor cores still run at 200 MHz.

6.2 Interfaces

Software freezes when initializing the Ethernet Interface

Software that relies on the MDIO interrupt for Ethernet PHY initialization may time out when

bringing up the Ethernet interface. This is an issue with some version of the Linux kernel

included in the SnapGear GNU/Linux distribution provided by Aeroflex Gaisler. A general

quick fix is to attach a network cable to each Ethernet port that is being initialized. The long

term fix is to contact the software vendor and ask for an update.

I have problem X when using the USB Debug Communication Link

The USB Debug Communication Link has a bug that leads to repeated accesses. This is a

problem when accessing register interfaces that are FIFOs, that is the interfaces are affected

by being read or written more than once with the same value. Therefore the USB Debug

communication link must not be used when interacting with a UART (for instance when using

the -u flag to GRMON) or using the SPIMCTRL or SPICTRL cores.

Also, jumper J10 17-18 (GPIO 43) must be installed at power-on for the USB DCL interface

to work.

The system freezes when using it together with my PCI device

The GRPCI core's PCI target interface included in the design has a bug that causes it to

perform bursts of infinite length if a PCI master performs a burst of eight or more words.