3.3.1. Chip driver settings dialog

If you double-click on the square outline of the core in Figure 3.8 the Multi-ICE server provides more information about the devices it is connected to. The device information is obtained by reading the device TAP controller settings and interpreting them according to a standard table that is built into the server. The dialog box is shown in Figure 3.9.

At the top of the dialog box the List of Drivers contains the names of the Multi-ICE drivers that are applicable to a particular TAP controller. The list always contains the main driver (the ARM940T in Figure 3.9), which has a positive IR Length. It might also contain alias drivers, declared in the irlength.arm file with an IR Length of zero. An example of this is an ARM920T with an ETM attached.

Information in the Driver Details region of the dialog box changes for every connection, and so also between each device in the List of Drivers:

Connected To

The name assigned to the connection.


The time this connection was made.


The connection number assigned to the connection, which is also visible in the RPC Log file.

Vers. Reqd

The version number of the server protocol that the client requested when the connection was made.

Figure 3.9. TAP driver status dialog

TAP driver status dialog

Information about the device itself is available in the Device Details region of the dialog box. Other than the Device Name, the information in this region does not change when a different driver is selected in the List of Drivers because it relates to the device, not the driver used.

The dialog box contains the following items:

IR Length

The length in bits of the Instruction Register, a primary element in the JTAG TAP Controller.

Device Name

The name given to the device.

Device No.

The number assigned by the manufacturer of the device.

Version No.

The chip version number.


A textual version of the manufacturer number.

Man No.

The JTAG manufacturer code.

The device, version, and manufacturer numbers are read from the ID register in the TAP controller. Values in this register conform to the format shown in Figure 3.10.

Figure 3.10. TAP Controller Device ID register format


According to the IEEE 1149.1 specification for device identifiers the value 0xF0F0 in the Device No. field and 0x787 in the Man No. field is invalid.

ARM Limited puts these values into the device logic when the logic is supplied to the silicon manufacturer, with the intention that it is overridden with manufacturer and device-specific codes.

If the default ARM values are not overridden, the Multi-ICE DLL uses the string UNKNOWN (Generic ARM) as the manufacturer. The device name and part number are determined from the device characteristics when this is possible. When it is not possible the device fails to autoconfigure and must be manually configured. Multi-ICE also displays the true manufacturer number and string if this can be determined.

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