Windows host server for devc-amctap serial communications manager (QNX Neutrino)


For PowerTAP:

devc_amctap_host [options] 
-p ip_address -s path -a address -m size

For WireTAP:

devc_amctap_host [options]
-w lpt -s path -a address -m size

Runs on:

Windows hosts (consult the AMC documentation for Windows platforms supported)


Note: For PowerTAP, options -p, -s, -a, and -m are mandatory. For WireTAP, options -w, -s, -a, and -m are mandatory.

-a address
Location in RAM of the communication channel (as reserved by the startup -r option)
-b access_size
JTAG byte access size (1, 2, or 4 bytes, default 4). For best performance, use the largest value supported by the processor.
-i ip
Explicitly specify the IP address of the host server (the default is the the host's IP).
-f freq
Specify the JTAG clock frequency in MHz (1, 2, 4, 8, 12, 16, 24, or 32; the default is the JTAG's default).

AMC's recommended settings for PPC:

Processor: Max rate (MHz):
603 16
603ei 16
8240 24
8260 16
740 32
750 32
755 32
7400 32
8xx Debug clock = Bus speed/3

-m size
Size in bytes of the communication channel (as reserved by the startup -r option).
-n name
Requested CPU name. Some CPUs require the CPU's name to be passed to the JTAG to configure the processor. For more details, consult the AMC documentation.
-o port
Explicitly specify the PORT of the host server (defaults to 3490).
-p ip
Specify PowerTAP JTAG configured with IP.
-r poll_rate
Rate at which to poll the communication channel via the JTAG, in microseconds (1 - 999,999, default 50000).

Note: Polling too quickly reduces the performance of the target, since the processor must be halted each time the communication channel is polled.

-s path
Path to the location of the AMCTAP support files (amctap_powertap4.dll, amctap_wt_powertap4.dll, *.jtag)
-w lpt
Specify WireTAP JTAG on LPT (1 - 4) port.


The AMC WireTAP and PowerTAP development tools are hardware debuggers for embedded hardware. They enable you to control the target CPU and read from and write to target memory and registers. The devc-amctap manager provides a serial communication gateway through a JTAG connector to a target system that lacks free debugging serial or Ethernet communication ports, or for which no drivers are yet written.

The communication port consists of two components:

These two components communicate using a protocol mapped to use a particular region of reserved RAM memory (using the startup -r option). The virtual serial driver running on the target system appears and behaves as a standard serial port to target applications, enabling them to invisibly communicate with the host. The host server associates an IP address and PORT to this communication channel, enabling host applications (such as telnet for console, gdb for debugging) to seamlessly communicate with the target.

Note: This communication link is slow, about 9600 baud or less, and should be used only if there are no other communication options available (e.g. in deeply embedded systems).

The devc_amctap_host server is intended to connect the development host to a target that does not have any serial or Ethernet communication links, but that does have a suitable JTAG available. Without conventional links to download the target image, you have to use one of the following two options:

Boot the target first

The communication server must halt the CPU each time it polls the communication channel. It does not begin polling until after it has received a socket connection from an application on the host. To make sure that polling does not interfere with the boot process, applications should not initiate the connection to devc_amctap_host (using telnet, gdb, or the IDE for instance) until after the target has been booted.

Note: Doing a serial download while the devc_amctap_host server is polling target memory may prove to be catastrophic because the download may alter the timing of the target system.

AMCTAP software

The AMCTAP software interface is required to use this driver (contact AMC for details).

AMCTAP includes the following files:

Note: AMCTAP 4.3 currently performs much faster than AMCTAP 4.5. We recommend that you use version 4.3 unless you encounter problems with a particular CPU.


For information on installing PowerTAP, see the AMC documentation.

For a WireTAP Installation (for Win2k, Winnt), follow this procedure:

  1. Copy parllio.dll, parllio.lib, and parllio.sys to the \winnt\system32 directory
  2. Run the parllio.reg registry file. Its contents should look like this:

    "DisplayName"="Zeecube Direct I/O PPort Driver"
  3. Run the WireTAPzeecube.reg registry file.
  4. Reboot.

See also:


Character I/O drivers (devc-*) in the Utilities Summary