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The table below lists the Z8 Encore! microcontroller itself and all essential support circuits.
|
Ref. Des. |
Description |
Source |
Part # |
Qty |
|---|---|---|---|---|
|
- |
68-pin PLCC Socket |
Mouser (page 744) |
151-1568 |
1 |
|
U1 |
Z8F6422VS020SC |
Mouser (page ???) |
692-Z8F6422VS020SC |
1 |
|
C1, C4-6 |
Capacitor, 0.1µF |
Mouser (page 478) |
80-C410C104M5U |
4 |
|
X1 |
18.432 MHz Crystal |
Mouser (page 508) |
520-HCU1843-20 |
1 |
|
C2, C3 |
Capacitor, 20 pF |
Mouser (page 484) |
140-50N5-200J |
2 |
|
R3 |
Resistor, 100 kohm |
Mouser (page 380) |
291-100K |
1 |
|
R4 |
Resistor, 220 ohm |
Mouser (page 380) |
291-220 |
1 |
|
R5, R6 |
Resistor, 33 kohm |
Mouser (page 380) |
291-33K |
2 |
|
S1 |
Switch, pushbutton |
Mouser (page 806) |
612-TL1105WF100Q |
1 |
|
J1 |
Header, 6-pin † |
Mouser (page 691) |
517-[5/6]121TN |
1 |
There is not much room to economize here. A cheaper Z8 Encore! MCU with less memory would be suitable if you know you won't regret it. Many different crystal frequencies are available at the same price, see the Mouser catalog for details.
† The 6-pin debug header is cut from a longer header strip which costs more than is shown. Specify right-angled pins for compatibility with the ZiLOG Smart Cable or straight pins for use in an enclosure with a Target Interface Module.
The Z8 Encore! Option Kit is no longer available from ECROS Technology due to lack of demand.
The main board uses the Z8F64x2VS020SC MCU. This has 64 Kbytes of Flash ROM, 4 Kbytes of register file (RAM) and is packaged in a 68 pin plastic leaded chip carrier (PLCC). It is in a socket, so that it can be replaced with pin-compatible devices such as those with less memory. The Z8F64x2 has 14 fewer general purpose I/O pins than the Z8F64x3 in the 80 pin quad flat pack (QFP). However, it is more suitable for hand assembly and can be placed in a socket for removal and replacement. In production, the 64 pin TQFP could be used. This has exactly the same signals except for two power and two ground pins.
A PLCC chip is no more difficult to get out of its socket than a dual-in-line chip once you get used to it. It needs to be prized up with an inexpensive tool or pulled straight out with a much more expensive one. However, the cheap tool is not a flat-bladed screwdriver. A paper clip can probably be bent to do the job, or you can get a proper extraction tool. You can order one of these from ECROS Technology.
The Display Option uses 11 GPIO pins that do not have alternate functions. Even with the LCD installed, all alternate functions are available to the user.
The crystal oscillator circuit is as specified by ZiLOG, including the power limiting resistor. A resistor in parallel with the crystal is specified for the Z8F6402 but not the Z8F6422, therefore R3 should be omitted if the latter is used. The standard crystal frequency is 18.432 MHz. For other frequencies, you can get a board without a crystal and use your own.
The RC oscillator mode can be used by installing the capacitor as C3 and the resistor from the junction of R3 and C3 to a conveniently place VDD test point nearby. X1, C2, R3 and R4 should be omitted.
Important: Using ZDS II to fill Flash memory with binary patterns can put the Z8 Encore! MCU into a mode in which it will only operate with an external RC oscillator. With the crystal oscillator, the board will appear to be "dead". Swapping the MCU will fix the board, but the MCU can only be recovered by putting it in a board with an RC oscillator circuit. So, if you must directly change the contents of Flash memory, be careful what you put in the first two locations (the option bits)!
A debug header is provided that is compatible with ZiLOG tools. There are two positions in which this connector can be placed, both on the left hand edge of the board. A right-angle header can be mounted so that it protrudes over the edge of the board slightly. This arrangement can be used with the Target Interface Module (TIM) or the Smart Cable. If the board is to be placed in an enclosure, a hole must be cut to clear the pins. A straight header can be mounted closer to the edge of the board, but with the pins sticking straight up the board fits into an enclosure without a hole. This arrangement cannot be used with the Smart Cable. It can be used with the TIM mounted vertically or with the ECROS Technology "Tiny-TIM".
ZiLOG and Z8 Encore! are registered trademarks of ZiLOG inc.
Copyright © 2004, ECROS Technology, all rights reserved.