ARM Technical Support Knowledge Articles

What are the differences between a revision B and revision C EB?

Applies to: EB (Emulation Baseboard)


[New 15 Aug 06]

Most ARM development boards go through one or more prototype stages before being put into production. Each different PCB version is given a revision letter, starting at ‘A’.

The first production batch of EBs were RevC, but there were a number of pre-production, RevB boards that were sent to customers – mostly as ‘early access’ units for the ARM11MPCore device. Later, the boards were updated to RevD, mainly to bring them in line with the European RoHS directive (please see related FAQ).

This FAQ describes the practical differences between the RevB and RevC versions of these systems, and what level of support is available for each.

There are differences in the fixed hardware of the two system versions, which make the FPGA images incompatible. As a result, the decision was made to offer only ‘Limited Support’ for RevB boards.

The released RevB baseboards were supplied bundled with a RevB CT11MPCore Tile and programmed with an FPGA image that supports the CT11MPCore Tile. This FPGA image and accompanying documentation is known as App Note 152.

This FAQ concentrates on a system comprising an EB and a CT11MPCore Core Tile, but is also relevant to users wishing to use other EB Application Notes (146, 148 and 151), since these will not work with a RevB EB, due to the hardware differences described hereafter.

The following table lists the versions of the EB and CT11MPCore boards produced to date, and their support status:


EB PCB Part #

CT11MPCore Part #

Support Status




First prototypes – None were released to customers




Second prototypes - Some were released, with ‘Limited support’, as explained in this FAQ




First production release – Fully supported.





Second production release – RoHS compliant (Lead Free) boards – Fully supported.

Identifying your EB

The board version number is etched into the top copper layer of the PCBs. On the EB, this is near the 2-line LCD. On the CT11MPCore, this is on the corner of the board, where HDRX and HDRY meet. These locations are shown in the following photographs:

Low res photo of HBI number location on EB EB part number location

  Low res photo of HBI number location on CT11MPCore CT11MPCore part number location

Differences between RevB and RevC EB + CT11MPCore systems

Programmer's model differences

  • The CT11MPCore internal register block has moved from its original location of 0x10100000 on the RevB board to 0x1F000000 on the RevC board.
  • The SYS_PLD_CTRLx registers in the EB FPGA appear at different addresses in the system memory map:










Note that these registers are referred to as SYS_PLDCTL[2:1] in the EB user guide (ARM DUI 0303A).

  • The RevB EB had 2MB of pSRAM on CS2 at 0x48000000. On the RevC EB, this was increased to 4MB.

Fixed Hardware differences

In addition to the CT11MPCore register block and pSRAM changes described above, a number of minor modifications and improvements were made to the fixed hardware of the RevB EB baseboard and CT11MPCore. These do not affect the system from a programmer’s perspective; however they do mean that the RevC AN152 FPGA image is not compatible with the RevB board and vice-versa. These changes are detailed on the last page of the PCB schematics for the EB and CT11MPCore.

AN152 FPGA image differences

The most up-to-date FPGA image for a RevB EB system (EB and CT11MPCore at RevB) is build B29. The first RevC systems (EB and CT11MPCore both at RevC) were shipped with FPGA build C1.

Differences include:

  • The B29 image used DIP switches S8[8:5] to control various clock speed settings in the system. In the C1 image, a much simpler set of adjustments can be made.

AN152 firmware (Boot Monitor) differences

The RevB EB systems were shipped with Boot Monitor version 3.2.x. RevC systems were shipped with version 3.3.x. Version 3.3.2 auto-detects whether it is running on a RevB or RevC board, so it is advisable to use this version for both board versions. Note that subsequent versions may not be backwards-compatible with the RevB boards. EB Boot monitor can be downloaded from the RealView Downloads area.

Limited Support on RevB boards – what this means in practice

FPGA, Firmware and software

Because RevB EB systems were essentially prototypes, any future bug fixes or enhancements to the AN152 FPGA design, the Boot Monitor or other software such as ARM Embedded Linux will likely not be backwards-compatible with a RevB system.

Other EB-based App Notes (listed above) will not be re-worked to support RevB EB baseboards.

In theory, there is nothing to stop the end user re-building an FPGA design, Boot Monitor or OS image to work with the RevB boards’ fixed hardware or memory map, but we cannot offer assistance for this activity.


The first user guides published for the CT11MPCore Tile and EB (ARM DUI 0303A) relate to the RevC board hardware. The suggested way of obtaining definitive information about the operation of a RevB EB + CT11MPCore system is to use the RevC user guides as a starting point, and verify operation by cross-referencing with the register descriptions, etc. as defined in the RevA App Note and FPGA Verilog source files.

A separate FAQ discusses the correct documentation for each revision of the EB + CT11MPCore Tile hardware.

ARM Tech Support

Since these are 'non-standard' systems, we are unable to offer technical support for RevB systems, other than what is contained in or referenced from this FAQ.

Upgrade policy

If you have a RevB EB system, and would like to upgrade to current hardware, please discuss this with your local ARM sales office. The terms of any upgrade would depend on the exact circumstances under which the RevB system was supplied to you.


Attachments: img14492.jpg , img14396.jpg

Article last edited on: 2009-01-20 16:45:11

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