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With the proliferation of single-chip C166 variants the use of an in-circuit emulator is becoming more important than ever. This is mainly due to program execution from on-chip ROM being some 30% faster than from an external 16-bit non-multiplexed bus. With devices like the C164CI being limited to a multiplexed bus only, the performance gain from going on-chip is >50%. The only way to debug code in-target at full speed is thus with an emulator like the DProbe167.

Even if you intend never to use an emulator it is still worth taking some basic steps that will allow you to use one if you get a particularly difficult debugging problem that requires an emulator to be hired. This document outlines the main methods of connecting an emulator and the steps that need to be taken when designing your board.

QuadConnect	A Hitex proprietary (but much copied!) method based on the incorporation of a series of pads around the CPU that can accept a special connector. This is incorporated in all the Infineon starter kits like the SK-C167CR.
PressOn	Another Hitex proprietary method of connecting to a soldered-in C167 design.
Yamaichi Socket	A special emulator adapter that screws into a Yamaichi MQFP or TQFP socket.
Solder-In Replace Adapter Or "Stack"	A special one-time use "stack" that solders to the unpopulated pads of a C16x CPU.

What follows examines which method is best for common design situations.

This is the cheapest and most robust connection method, requiring four groups of two rows of pads around CPU, usually on a 0.5mm or 0.050" pitch. For emulation use, these pads are populated with commercially available SAMTEC connectors, available from Genalog in the UK (01580 753754). The fitment of the DProbe emulator causes the soldered-down CPU to tristate it pins via a pull-down resistor on Port 0.1 ("ADAPT Mode"). The emulator's bondout CPU takes over.

Things to watch out for:

• The QuadConnect requires some board space, which may rule it out in some designs. It is however very reliable and the unpopulated pads can be used for end-of-line testing in production.
• As there are effectively now two CPUs being driven, a discrete crystal clock circuit may not be sufficient. In such cases decreasing the load resistor value in the clock circuit may be needed or the DProbe variable frequency clock generator can be used. Note: if you contemplating not using a Hitex ICE, make sure that the unit you choose has a clock generator that can be easily varied, preferably by software. An Oscillator Module is an alternative to a Crystal. There are no load resistors to calculate and they provide sufficient drive, but they are more expensive. You may consider laying the board out for both a Module (during development) and a Crystal (for production). Also look at the Infineon Users Manual for the part being used and the Application Note AP24200S particularly if you don’t intend to use the PLL. The tolerances for the Clock Signal are stringent at X1 (this applies to the Target with and without an ICE).
• Do not add a pull-down resistor on P0.1 on your design as the DProbe will do this for you. Any additional pull-up or pull-down resistor may cause problems!
• When deciding on the orientation of the CPU on the PCB, make sure that the body of the DProbe does not foul any components or other mechanical parts. A drawing of the DProbe with the pin one position can be found at http://www.hitex.co.uk/c166/dprobe167.html. It is worth noting that the DProbe167 has the smallest footprint of any current C166 family emulator. Note most QuadConnector boards have a 90 degree Pin1 Shift.
• If it is necessary to raise the level of the DProbe167 above the board to clear tall components, a clearance adapter is available that will increase the height by 15.6mm. These adapters can be stacked to give additional clearance.

Drawings of QuadConnect layouts for all C167 designs are available from the Hitex Website at http://www.hitex.de/pdf/adapter/adapter.pdf .

QuadConnect Advantages

• Very cheap and robust in use

QuadConnect Disadvantages

• Requires significant board space
• May require changes to crystal-based clocks.

If you are contemplating using either PressOn or QuadConnect on your design, please do not hesitate to call Dave Greenhill at Hitex UK to discuss what is involved!

The PressOn was originally developed to meet the needs of the German car industry to allow soldered-down CPUs to be emulated without any changes being made to the target hardware design. Like the QuadConnect it relies on the soldered-in CPU tristating. The PressOn uses a conductive flexible elastomer material to make contact with the shoulders of the CPU's pins. This is similar to the flexible conductors used to connect flat screen LCD panels onto portable PCs. The contact assembly is secured to the CPU package by using a special cyanoacrylate adhesive ("superglue") to attach a threaded stud. This glue is designed to be strong in tension so that the stud cannot be pulled off, but weak in shear so that can be easily twisted off with a scalpel. A solvent is then used to remove any glue residue. It is the (patented) technique of gluing a stud to the CPU package that gives the PressOn its reliability in real applications. It is far more durable than alternative methods that rely simply on friction to retain the adapter. Indeed, in the UK we have run car engines on rolling roads with the engine management system under the control of a DProbe connected via a PressOn. The UK's largest automotive systems developer also makes extensive use of the PressOn.

PressOn frames are milled out from a sandwich of 6 different materials (see picture below), including a flexible PCB layer. The CPU contact frame is machined from a rigid plastic material to ensure an accurate fit over the CPU package.

The 0.5mm pin pitch used on the C16x family can be accommodated by current PressOn technology without problems.

The contact elements are largely hand-made and by using 6 gold conductors per millimetre the PressOn does not need precise alignment and guarantees a reliable connection to the target CPU. Despite the apparent fragility of the PressOn, at least 500 connection and disconnection cycles should be possible. If the contact elements do become damaged they can be replaced by returning the PressOn to Hitex UK at a cost of around £100. To allow some relative movement between the CPU and emulator, the PressOn uses flexible sections.

All of this adds up to a rather expensive connection method but where there is insufficient space for a QuadConnect it is only alternative. The key requirement for the successful use of the PressOn is the cleanliness of the CPU pins. Thus all solder flux residue and oxidation must be removed using the special tools and solvents included in the PressOn installation kit.

The apparently high price of PressOn’s has prompted some US manufacturers to try and produce of copies of the PressOn. However as the concept of fixing a stud to the top of a CPU is protected by a Hitex patent, these rely on forcing mica "wedges" with conductive strips between the CPU pins to fix the assembly. This requires some extremely thin mica partitions between pins, which wear out very quickly, and because they rely on simple friction to anchor the adapter to the CPU they quickly become loose and fall off easily. Other methods rely on small grubscrews at the corners of the adapter, which are very awkward to tighten and quickly damage the CPU package. Both these compromise methods are easy to detach accidentally and are not suitable for use under vibration conditions. They also use a rigid connection to the emulator and so twist off very easily. Common engineering sense says that the only secure place to put the fixing device is on top of the CPU and only the PressOn can do this.

Please be assured that Hitex endeavours to keep the price as low as is consistent with the very high quality of manufacture that is required. There is no current CPU connection technology that provides such a reliable connection to a soldered device as the PressOn.

Points To Watch Out For:

• You will need to leave 4mm of clearance around the CPU pads to accommodate the PressOn contact frame. You may also need to make sure that no tall components are within 25mm of the edge of the pads.
• If there is no space around the CPU at all there is a special rigid "tower" type PressOn available. This should only be used after discussion with our specialists.
• In most cases, simply cleaning the CPU pins with propanol is enough to guarantee a reliable connection. If there is significant contamination of the pins, a special (supplied) tool must be used to remove any oxidation and solder flux condensate/residue before fitting a PressOn.
• Do not add a pull-down resistor on P0.1 on your design as the DProbe will do this for you. Any additional pull-up or pull-down resistor may cause problems!
• As the PressOn completely obscures the CPU pins getting at them with a 'scope probe is almost impossible. To get around this, we have produced a "breakout" adapter that brings out all the CPU pins around the DProbe167 itself. The part number is DZS167-M144-QCT.

PressOn Advantages

• Allows emulation of any soldered-down C16x derivative
• Requires no changes to target board design
• Reliable connection, even in high-vibration environments
• Any board can be emulated, even production examples

PressOn Disadvantages

• Relatively high cost
• Does not like rough treatment!
• Requires cleanliness and some care to assemble

Drawings of PressOn layouts for all C167 designs are available from the Hitex Website at http://www.hitex.de/pdf/adapter/adapter.pdf

Until the release of the PressOn adapter this was the most popular emulation connection method. It relies on fitting a Yamaichi socket instead of a CPU. It has a screw-clamped CPU retaining ring, which is replaced by the emulator adapter (also made by Yamaichi), for development work. Apart from requiring a CPU pad-length increase of 2mm, this method has relatively little impact on board design but will require the production of special socketed boards. The sockets are expensive and the emulator adapter is more costly than the QuadConnect equivalent.

There are drawings of the Yamaichi sockets on the Hitex CD-ROM in \PDF\ADAPTOR\APP. Yamaichi also have an extensive set of drawings at www.yamaichi.de

Points To Watch Out For:

• The socket requires pads that are 2mm longer required by a standard CPU and needs up to 4mm clearance around the CPU.
• There are sometimes two very similar sockets of the same number of pins. Make sure you use the right one! There is a table to follow that gives the common ones.

Yamaichi Socket Adapter Advantages

• Very reliable
• Allows the fitment of a CPU so that the board can be run without the ICE

Yamaichi Socket Adapter Disadvantages

• Sockets are expensive
• Sockets are difficult to fit unless a hot air gun is used
• Requires longer than standard pads

Instead of soldering down a CPU, prototype boards for use with the DProbe can be fitted with a solder-in "stack" which mates up to the underside of the emulator. They solder directly to standard CPU pads so are one-time use but are very reliable and require no more board space than the CPU itself. They are relatively expensive in the UK.

Solder-In Replace Adapter Advantages

• Will fit to standard CPU pads
• Very reliable

Solder-In Replace Adapter Disadvantages

• Difficult to solder with a standard soldering iron
• Can be soldered-down only once or twice
• In most cases the PCB cannot be run with a standard CPU. Although some "stacks" have a mating half containing a socket for the processor. The Emulator can be "unplugged" from the stack and then the board containing a processor plugged in.

When placing the CPU on the PCB layout it is sensible to bear mind the solderability of the package. It is a good idea to consult your PCB manufacturer and assembler if you have not used high-density MQFP and TQFP devices before. With the C161CI and C167 especially, there are a large number of pins and solder shadowing can occur. In some instances, the CPU is mounted at 45 degrees to the solder wave to eliminate this effect.

When mounting the SMD QuadConnect connectors on the PCB, use the proper Hitex QuadConnector as a jig to hold the strips in the correct position. If you have not yet got one of these, please call us to arrange the loan of a suitable part.

Here is a list of which socket part numbers are used for the various members of the C166 family.

CPU       Package Type   Pin Pitch SMD Socket      Yamaichi Part No.

166       P-MQFP-100-2   0.65 mm  SOMQ100-Y        IC149-100-014-S15
165/161RI P-MQFP-100-2   0.65 mm  SOMQ100-Y        IC149-100-014-S15
164       P-MQFP-80-1    0.65 mm  SOMQ80-1-Y       IC149-080-017-S5
163       P-MQFP-100-2 Low cost Production Socket  IC198-1001-210*
165/161RI P-TQFP-100-3   0.50 mm  SOTQ100-Y        IC149-100-025
167       P-MQFP-144     0.65 mm  SOMQ100-Y        IC149-144-KS11453-0S
161O/K/V  P-MQFP-80-1    0.65 mm  SOMQ80-1-Y       IC149-080-017-S5
161O/K/V  P-MQFP-80-2    0.80 mm  SOMQ80-2-Y       IC149-080-021-S5
161Ci/SI  P-MQFP-128     0.50 mm  Not available

Common QuadConnector Part Numbers And Drawings

These drawings can be found on the Hitex CD-ROM at \PDFS\ADAPTER\SPECS. You can
download them also from our Website using the links in the table below.

CPU              Package Type    QuadConnector Part No.    PDF Drawing
C167CR/CS        144MQFP         DZS167-M144-QCS           QC144S.PDF
C164CI            80MQFP         DZS164-M80-QC             QC164CI.PDF
C161O/K./V        80MQFP         DZS161-M80-QC             QC161OVK.PDF
C163/5           100MQFP         DZS163-M100-QC            QC165M.PDF
                 100TQFP         DZS163-T100-QC            QC25X25.PDF
C161RI/PI        100MQFP         DZS161RI-M100-QC          QC161RIM.PDF
                 100TQFP         DZS161RI-T100-QC          QC25X25.PDF
C161SI/CI/SJ/CS  128TQFP         DZS161SI-T128-QC          QC161CIT.PDF

These drawings can be found on the Hitex CD-ROM at \PDFS\ADAPTER\DATA.
You can download them also from our Website using the links in the table below.

CPU              Package Type  PressOn Part No.       PDF Drawing
C167CR/CS        144MQFP       DZS167-M144-P          B5600202.PDF
C164CI            80MQFP       DZS164-M80-P           B5600213.PDF
           Horizontal offset PressOn                  B5600223.PDF
C161O/K./V        80MQFP       DZS161-M80-P           B5600203.PDF
C163/5           100MQFP       DZS163-M100-P          B5600205.PDF
                 100TQFP       DZS163-T100-P          B5600206.PDF
C161RI/PI        100MQFP       DZS161RI-M100-P        B5600215.PDF
                 100TQFP       DZS161RI-T100-P        B5600216.PDF
C161SI/CI/SJ/CS  128TQFP       DZS161SI-T128-P        B5600217.PDF

This drawing shows the size of the DProbe167 with the pin 1 position marked. (Size in mm)