Z8 Encore! XP Dual Series Development Kit

Editor Review

Ease of Set-Up:

Documentation Completeness and Clarity:

Hardware Completeness and Quality:

Sample Projects/Tutorials:

Meets Expectations:

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Overall rating:

Time to Complete

Prerequisite Skills

Experience programming with C.
 

What We Liked

Good hardware and development tools. Easy to set up. Out-of-the box preprogrammed demo worked right away. Simple eval board made it easy to use I/O pins on the 28-pin Z8F1680 MCU. Not cluttered with a lot of I/O devices.
 

What we Didn't Like

The  Quick Start Guide seemed choppy--much jumping back and forth between pages. Extraneous information included for other eval kits.  Additional documentation difficult to find. No list of CD-ROM contents. No information on where to go after a user runs the demo program. A bug in the Zilog Developer Studio II IDE (4.11.0) delayed using the software tools. (See Full Review text below.)
 

Full Review

Zilog's family of Z8 microcontrollers (MCUs) has existed for some time, but because of the company's low profile, developers might not know much about the wide variety of MCUs it offers.  The Z8F16800128ZCOG kit comprises an evaluation board, USBSmartCable, power supply, CD-ROM and a Quick Start Guide. Users have easy access to general-purpose I/O-port signals through two rows on pin headers beneath the board. A separate connector makes available analog-input lines. The Z8 Encore! XP family of devices comes in many package types with varying amounts of RAM, Flash memory, and I/O ports.

Except for a bug (easy to overcome once you know how, as explained below) in the integrated development environment (IDE) and the lack of tutorial materials for I/O port operations, the kit itself was easy to work with.  It provides a simple way to learn about the Z8 XP Encore! architecture and capabilities, and to try the Zilog Developer Studio II tools.

It took only a few minutes to set up the hardware. Attaching the USBSmartCable caused my Win XP lab PC to go through the usual USB device-driver steps to load the control software.  The CD-ROM includes the Zilog Developer Studio II IDE (ver 4.10.1), but I went to the Zilog Web site and downloaded the latest version, ZDS II, ver 4.11.0.  The installation places some demonstration code in a separate file of samples in the  ZDSII_Encore!_4.11.0 directory. The demo code folders include software for several families.

After the installer software sets up the ZDS II IDE and sample code, you connect the USBSmartCable to the eval board, and apply power to the board.  The USBSmartCable pulls the MCU's reset to ground and holds it there. With the board powered, unplug the 6-pin flat cable to release the MCU's reset input. The board's three LEDs should flash in sequence to indicate the presence of demo code, which shows the MCU works.  (Kits might not have this demo code installed, so don't give up hope if your board doesn't flash the LEDs at this point.)

The Quick Start Guide explains how to open an led-flasher project, build the code, download it to the target MCU, and run it. When I went through these steps, the ZDS IDE indicated it could not connect to the target through the USBSmartCable, so I came to a dead stop. Although I tried different sequences of cable connections, power, and reset, communications did not occur.

NOTE: The samples directory includes code for several MCU types, so pay attention to the path you follow. Other families have their own ledBlink.zdsproj files.  So, if a demo program does not behave properly, ensure you have followed the path for the processor in use.  When you want to open the demo project, ledblink.zdsproj, for this kit follow this path:

Program Files\ZiLOG\ ZDSII_Encore!_4.11.0\samples\XP_F1680\XP_F1680_28Pin_ledBlink\src\ledblink.zdsproj


A Problem with ZDS II Version 4.11

Because I couldn't overcome the USBSmartCable communication problem, I filed a request for help via Zilog's online support system and got a reply that offered suggestions, but they didn't help.  The online tech-support person responded within a few hours, which I consider good.  I finally called a Zilog person and he went through the setup with me.  Same results.  Then we discovered a problem in the ZDS II IDE (ver 4.11).

Here's a description of how to overcome the problem, or bug, in the ZDS II IDE.  During setup of the USBSmartCable users must ensure they have set the correct debug properties: Click on Project-->Settings... Then, in the Target window, ensure the IDE has checked the proper kit type. In this case, you should have Z8F16800128ZCOG checked.

Next look at the Debug Tool section and ensure that the IDE has selected USBSmartCable.  If not, use the drop-down menu to select it.  DO NOT click OK.

In the Debug Tool section, click on Setup to open a window labeled Setup USB Communications.  You will see a window labeled Serial Number that shows the internal serial number of the USBSmartCable.  (You can use the Windows Device Manager to confirm this is the correct serial number.)

Although the number shown will match the number of the cable, you MUST click on the downward arrow at the right end of the serial number window to display all serial numbers, although you'll likely see only your cable's serial number.  In the drop-down window, YOU MUST CLICK on the serial number itself. You must perform this selection step, even though the Serial Number window already shows the correct serial number.  If you skip this step, you'll end up at a dead stop just like I was.

After going through the steps above you can build the ledBlink project and download the code to your target eval board. You should not see any error messages.  I went through these steps with the guidance of my Zilog contact and the eval board worked well.

I decided to modify the code to create an 8-bit binary counter, and connect a logic analyzer to confirm the I/O port worked properly under software control.  I chose Port C because except for a connection with a red LED, the other pins were unconnected.  Learning how to set up Port C became a chore.  I downloaded the 399-page "Z8 Encore! XP F1680 Series Product Specification" (PS25008-0608) and printed the GPIO Control Register Definitions pages. They confused me because each port has subregisters that will control a high-drive enable, pull-up enable, and so on for each port.  Although the product-spec manual describes these registers, it lacks examples of how to use them in real code.

After I reviewed the gpio.c and main.c code listings for the ledblink project, I thought I understood how to set up and control Port C.  Unfortunately, the ledblink programmer (the person) made things overly complex.  To set a bit in the Port C data-direction register to configure bit D3 as an output, the programmer used the following:

#define LED_RED_PIN    3              //PC3  [port C, D3 pin]

PCADDR  =  0x01;                //Select the data-direction register

PCCTL  &=  ~(1<<RED_LED_PIN);    //???

The latter statement shifts a logic 1 in bit D0 three places to the left, complements that value, then performs a bitwise logic-AND with the value in the PCCTL register.  Why not simply establish a mask of 11110111 to start and then do the bitwise AND?  You might use the type of code above in a design, but come on, these samples are supposed to help people understand the demo code, not show off a programmer's skills.  Keep it simple and educational. (The bitwise AND operation shown above sets bit D3 at port C as an output bit bit it leaves the other data-direction register bits unaltered.)

The statement:

PCCTL = PCCTL & 0xFB:  //11111011 mask

will do the same thing, but it's simpler and easier to understand.

For more information about how to use the GPIO ports, read "Using the GPIO Pins of the Z8 Encore! MCU," (TN002401-0304).  I found that document after struggling with the product specs noted earlier.  I did get the binary counter to work within the ledblink framework, after I stripped out the LED-flash and timer code. But even the examples in the GPIO technical note seem too complex.  How about an example that shows how to set up the simplest output port and the simplest input port.  Start at the most basic level and go on from there.

By the way, a Link Instruments MSO-19 scope-and-logic analyzer on my host PC confirmed the proper operation of the 8-bit counter.

The ZDS II IDE makes it difficult to save a project in folder other than the one you already have it in.  That means if you modify, say, the ledblink.zdsprj project, it will overwrite the original ledblink.zdsproj folder.  To get around this, you must first set up a new folder for your revised project, copy the old project to this directory, work on the project and then save it into the new folder.  That creates a lot of work and could make for a version-control mess.  "What did I just save, and where did it go?"

The Save Project choice should include a Save Project As... option that sets up a new folder and drops the version you're working on into it.

Zilog has made a good effort to organize information about its development kits on its Web site so people can find related materials.  When searching for Z8F16800ZCOG information, the Zilog Web site produces the kits general specifications as well as a list of information about the tools, documents of interest, and general information. Unfortunately, the document list doesn't include the helpful GPIO technical note mentioned earlier.

A larger, printable, readable schematic diagram would help. I enlarged the I/O-pin header section and wrote in pin names, but transposed the PC5 and PC6 labels because the printed diagram was difficult to read.  Unfortunately, when you complete the LED-flash experiment, the Zilog information doesn't provide guidance about what to do next. So you may find yourself paging through manuals to try to figure out how to do simple things.  Also, the Zilog Web site doesn't seem to offer any additional tutorials that explain how to create a project on your own.

This kit got a low grade for Documentation because some information is difficult to find and it got a low grade for Samples due to the lack of basic tutorial information. As a result, although the kit has good hardware and development tools, the Meets Expectation grade rated only a 3. --Jon Titus
 

Samples & Tutorials

This kit includes one "canned" project but no other tutorials and no links or pointers to other information that would help you start a project on your own.  Unless you have a lot of spare time and energy, you will get frustrated with the lack of a clear path forward from the quick-start guide.

Z8 Encore! XP Dual Series Development Kit Review

About the Editor

Jon Titus

Sr. Technical Editor

Evalkits.com

jon.titus@evalkits.com

Jon Titus regularly contributes articles on electronics and measurement. He has extensive experience designing with microprocessors and microcontrollers, and developed data-acquisition and instrument-control systems and taught many courses on software and hardware design. A recipient of the George R. Stibitz Computer & Communications Pioneer Award, he holds a BS from Worcester Polytechnic Institute, an MS from Rensselaer Polytechnic Institute, and a PhD from Virginia Polytechnic Institute.

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