Issue
161 December 2003
Easing
into eZ80Acclaim!
by
Fred Eady
Zilog’s
eZ80Acclaim! development kit is filled to the brim
with hardware and software. It would take you some
time to get familiar with the various parts and
documentation. Fortunately, Fred has studied all
of it, and this month he shares his findings in
an effort to ease you toward your own eZ80Acclaim!
applications.
Start
•
eZ80Acclaim!
Applications
• How
EZ Was That
• EZ
Does It
• Sources
and PDF
Guitar
strings are like tires on your automobile—every now
and then you’ve got to replace them. Luci, my black
Fender precision bass guitar, was way overdue for some
new twangers, so I purchased a set of heavyweight strings.
After stringing her up, I struggled to fret notes cleanly,
because the heavyweight strings were really tough to
press into the guitar’s fretboard.
After
living with this heavy feeling for about two days, I
was so frustrated with the feel of my beloved Luci that
I went to the lab and dug out a pair of diagonal wire
cutters. I immediately put the heavier strings out of
their misery (and mine) by snapping them in half. Before
the wire cutter coup, I had ordered lighter strings.
I lashed her up once again. After a quick tuning session
with Elton’s gift (a black Yamaha piano), Luci was putty
in my hands once again.
I
don’t recommend mixing your musical interests with diagonal
wire cutters. However, my little string story plays
well with this month’s subject matter. Zilog has been
aggressively pricing its development kits, and because
the price was reduced by $300, I had to take a look
at the new eZ80Acclaim! evaluation kit. It seemed like
a lot of hardware and software for the money. Shucks,
there are enough wires, cables, Ethernet hubs, wall
warts, and C compilers in the eZ80Acclaim! evaluation
kit to almost justify its $199 price tag.
After
I had registered my kit, I was surprised to find extra
software links on the registration page. I proceeded
to download the latest Zilog TCP/IP Stack V. 4.5.0 of
the Zilog Developer Studio II IDE and an Ethernet MAC
DDK.
EASY80
In
addition to all of the software, there’s lots of hardware
stuff in the Zilog eZ80Acclaim! evaluation kit. I managed
to work my way through connecting the two wall warts
to their proper devices. There was also a third wall
wart in the box that was pinned for use outside the
United States. It added to the confusion factor until
I removed its protective cover to find pins on the AC
side of the wall wart that wouldn’t plug into anything
in the Florida room.
One
of the wall warts (9 VDC) powers the main Zilog eZ80Acclaim!
evaluation board (see Photo 1a). The second wall wart
(5 VDC) provides power for the ZPAKII emulation device
(see Photo 1b). Sorting the wall warts was a no-brainer
because the ZPAKII power supply doesn’t fit the eZ80Acclaim!
evaluation board and vice versa.
|
(Click
here to enlarge)
|
Photo
1a—In addition to providing a port for the eZ80F91
module, the eZ80Acclaim! evaluation board allows
the addition of SRAM, a socket modem, and specialized
application modules. There’s also a JTAG interface
(light blue connector) and a ZDI target interface
module interface (dark blue connector) tied to one
side of the eZ80Acclaim! evaluation board. The application
module fits over the male I/O headers. b—The ZPAKII
is fitted with a serial and an Ethernet interface.
After everything was configured and running, I found
that I could disconnect the ZPAKII serial interface.
The ZPAKII sits between the Developer Studio II
and the ZDI target interface module, and is an integral
part in the debugging and emulation processes. The
ZDI target interface module is the module at the
other end of the ZPAKII ribbon cable. |
The
differing electronic areas of the evaluation board are
pretty easy to figure out. Everything that has to do
with serial communications (RS-232, RS-485, etc.) is
built around a couple of nine-pin shell connectors.
There’s an RJ-11 telephone interface as well as some
space and pins reserved for a Conexant socket modem.
A 5 × 7 LED array (Lite-On LTP-757), some push buttons,
and the I/O pin area take up most of the rest of the
board.
The
eZ80Acclaim! evaluation board came with an eZ80F91 module
plugged into a set of female headers next to the serial
area of the board. The eZ80F91 module is loaded with
goodies. The eZ80F91 microcontroller that resides on
the module is based on the eZ80 CPU core and can run
with a 50-MHz clock. The legacy Z80 addressing mode
(64 KB) and full 24-bit addressing mode (16MB) are supported
by the eZ80F91. Note that 1 MB of flash memory and 512
KB of SRAM support the eZ80F91.
The
eZ80F91 is a communications-capable monster. It comes
with an SPI and I2C interface, two UARTS, a 10/100-Mbps
Ethernet MAC, and an IrDA transceiver. Internally, the
eZ80F91 microcontroller contains 256 KB of flash memory
and 16 KB of SRAM. The internal SRAM is divided equally
between the CPU and the Ethernet MAC frame buffer.
At
this point, I know just enough about every component
in the Zilog eZ80Acclaim! development kit to be dangerous.
The last component that I had to figure out what to
do with was the ZDI target interface module. Fortunately,
connecting the module was idiot-proof because there’s
only one way to mate the connectors.
I
loaded all of the stuff on the CD-ROM that came with
the development kit, and I loaded the newly downloaded
applications that I had received when I registered it.
The development kit hardware also includes a four-port
Ethernet hub. Thank goodness I have a good idea of what
to do with that. A peek at the “Quick Start” guide reveals
a block diagram describing how to hook all of the hardware
components together using the Ethernet hub included
in the development kit.
I
didn’t want to put up another network just to support
the development kit. So, I decided to forego using four-port
Ethernet hub and plug the ZPAKII, eZ80Acclaim! evaluation
board, and eZ80F91 module into the Florida room’s existing
LAN.
The
development kit setup procedure involves addressing
the ZPAKII debugging device. Because I opted to use
an existing LAN, the default ZPAKII IP address would
not allow me to configure the ZPAKII using its integrated
’Net browser interface. The workaround is to use the
ZPAKII serial interface to change the ZPAKII’s IP address.
A combination of pressing and releasing the Z key while
resetting the ZPAKII via a recessed Reset button and
entering H for help brought me to the Tera Term Pro
screen you see in Photo 2.
|
(Click
here to enlarge)
|
Photo
2—You can use the ZPAKII’s serial interface to initially
set up the ZPAKII’s network parameters. I also turned
off password protection for the ZPAKII’s web browser
interface. |
While
I was in this mode, I also adjusted the subnet mask
and gateway IP addresses in addition to changing the
ZPAKII’s IP address to play on the Florida room’s LAN
segment. After resetting the ZPAKII, I called up its
’Net browser interface using the new IP address I had
assigned to it using the ZPAKII serial interface. All
was well with the ZPAKII up to this point.
I
had the ZPAKII powered and one side of it connected
to a port on one of the Florida room’s Ethernet switches.
The other side of the ZPAKII was attached via ribbon
cable to the ZDI target interface module, which is plugged
into the eZ80Acclaim! evaluation board. I also had an
Ethernet cable between the eZ80F91 module and another
port on the same Ethernet switch the ZPAKII is attached
to. Everything had power, and there wasn’t a hint of
smoke in the room. Let’s start digging through some
eZ80 code and applications.
