How to replace MC68HC908RF2 and its firmware?

[DRonWang]

By referencing AN1951, I am responsible to design TPMS for our customer. But I was told that MC68HC908RF2 will be phased out in the near future. So that I must try another solution (replacement), using MC68HC908QT2A and MC33493.

Can anybody advise whether the MC68HC908RF2 firmware of AN1951 can be directly ported into MC68HC908QT2A after slight modification? The only thing I concern is the communication between MC68HC908QT2A and MC33493.

If not, if there any advise, please kindly provide ASAP.

[bigmac]

Hello,

The 908RF2 device is capable of operation with a supply voltage down to 2V, whereas the 908QT/QY series are not.  If you require to operate from a single lithium cell, the 9S08QG8 device may be a better choice.  The existing firmware will need careful revision to cater for possible differences in bus frequency, I/O allocations, peripherals, etc.

I agree with Peg about the existing assembly code being in P&E CASM08 format.  This earlier thread refers to some of the differences between CASM08 and CW assembler.
http://forums.freescale.com/freescale/board/message?board.id=CWCOMM&message.id=501

Regards,
Mac

Message Edited by bigmac on 05-21-200601:26 PM

[DRonWang]

Thank you very much peg and bigmac.

I have already migrated into CW format and going to modify the program from RF2 to QG4.

But I found that the power consumption of RF2 is just 4.3mA while QG4 is 120mA at maximun run rate.

Our customer spec is 7-year life time with 500mA/hr battery. In the case, I am afraid, QG4 cannot reach the spec.

Does anybody knows which part number of MCU inside the RF2 is used?

[peg]

---

DRon Wang wrote:

Thank you very much peg and bigmac.

I have already migrated into CW format and going to modify the program from RF2 to QG4.

But I found that the power consumption of RF2 is just 4.3mA while QG4 is 120mA at maximun run rate.

Our customer spec is 7-year life time with 500mA/hr battery. In the case, I am afraid, QG4 cannot reach the spec.

Does anybody knows which part number of MCU inside the RF2 is used?

---

Hi,

The RF2 is an RK2 and a 33493 in the one package.

The 120mA you are quoting here seems to be from the absolute max ratings. This would be with all outputs sourcing etc and very worst case. This device is targeted at very low power applications and although I don't really know, I would be suprised if in the same application it draws more than the RF2/RK2.

The quoted run current at 3 volts and 8MHz in FBE mode with all bar analogue enabled is 3.5mA and drops to 490uA at 1MHz.

Regards David

[DRonWang]

Thank you very much for the replies. In this case, there will not be big problem at the H/W side.

But I am now having another problem on the software migration from source code of AN1951, using CodeWarrior.

In CodeWarrior, when I press "Make" buttom, the following Error will occur at the begining.

loadall

;/*****************************************************************************/
;/* PROJECT : Mosport State Machine Mimic   MODULE : MAIN                     */
;/*****************************************************************************/
; Initial version: Jeff Burgess

RAMStart        EQU     $0080
RomStart        EQU     $7880
VectorStart     EQU     $FFF2

$Include        'hardef.h'              {----Error : A1604

But when I modified the line into :

                     Include        'hardef.h'   {----Passed

then, it was passed.

So that I dare say the source code was not developped under CodeWarrior since the usage is different, I guess. I am not sure I am right as I am a beginner of Freescale MCU user.

If so, please kindly advise how to convert into CodeWarrior language or some other idea.

[peg]

Hi,

From the small sample provided, the code could have been written for P&E Microsystems assembler CAS08Z. You may find it easier to just use their tools to continue with the development. They are free at:

www.pemicro.com

or be prepared for a lot of make.. error.... search and replace... make.... error........

Regards
David

[carter]

Hi,

TPM sensor 's operating temperature is very high.

QG8 or QG4 's operating temperature only 85 degree.

Regards
Carter

[UK_CF_FAE]

Hi,

The firmware is going to be different. There's no alternative than to really understand the software in the apps note, and port it to the new MCU. Much of the code will need to be looked at in detail.

At Freescale we've made the software available, but you will need to take this and modify it for your customer.

I don't see any major problems specifically with the communications between mcu and rf chip.

Mark

[tonyp]

The RF2 is literally two chips in one.  The MCU and the UHF transmitter even talk to each using external pins.  It's no different than using two separate chips.  The code should work just fine.  Whatever differences, if any, will lie in setting up the MCU specific timers, etc.  As I remember the chip resembles a QT/QY very well.

Message Edited by tonyp on 05-18-200601:19 PM