topic Re: QG8 ASM sample code in 8-bit Microcontrollers

QG8 ASM sample code

admin — Mon, 24 Dec 2007 06:13:12 GMT

Hi guys,
I was wondering if there are any online resources on asm sample codes? Such as setting up port B for output and ADC etc.... am trying to migrate to QG8 from the hc11 and it has been a while since I did my project on that so am very rusty at the moment....

Thanks in advance!

Re: QG8 ASM sample code

admin — Mon, 24 Dec 2007 08:02:10 GMT

Hi,
I was wondering if someone can take a look at my asm and let me know if the set up code is enough to get the QG8 going?

ZERO           equ   $3f                 ;7 segment LED
ONE             equ   $06
TWO            equ   $5b
THREE      equ   $4f
FOUR       equ   $66
FIVE         equ   $6d
SIX           equ   $7c
SEVEN     equ   $07
EIGHT          equ   $7f
NINE          equ   $67
DOT           equ   $80

START        equ   $e000               ;FLASH
PORTB       equ   $0002
PRTBD       equ   $0003               ;port B direction
ICS1            equ   $0038               ;clock source
ICS2             equ   $0039               ;bus frequency

;setup

            lda   #%01000110          ;clock set up
            sta   ICS1
            lda   #%00000000
            sta   ICS2
            lda   #%11111111          ;setup portB as output
            sta   PRTBD
asm_main

            org   START
            lda   ZERO
            sta   PORTB               ;turn on 7 segment

            lda   #%00001111
            sta   PORTB
again       deca
            cmpa #%0
            bne   again
            lda   #%00000000
            sta   PORTB

the code passes the debug stage but how do I use the real time sim/debugger and load this into the QG8? I apologise for such a elementary question...

Re: QG8 ASM sample code

joerg — Tue, 25 Dec 2007 02:45:30 GMT

Hi
why not have a look at EBS08
see: www.systech-gmbh.ch -> EBS08

Saluti Joerg

Re: QG8 ASM sample code

admin — Thu, 27 Dec 2007 05:15:54 GMT

Thank you Joerg!

More of these type of links would be welcome, thank you everyone.

Re: QG8 ASM sample code

bigmac — Thu, 27 Dec 2007 10:50:45 GMT

Hello,

I might suggest that you use the "standardised" register names, contained within the file mc9s08qg8.inc, to be found within the CodeWarrior installation (..\lib\hc08\device\asm_include\). This file can then be INCLUDEd near the beginning of your main .asm file.

If you find that some of the standard bit names for the peripheral registers are a little unwieldy, it is possible to substitute an alias, for those bits specifically referenced by the code, e.g.

CPHA EQU SPIC1_CPHA ; Define alias for CPHA bit

BSET CPHA,SPIC1

can then be used, rather than

BSET SPIC1_CPHA,SPIC1

I suggest the following check list for initialisation purposes, for the QG8. Some of the intialisation will not be necessary if the peripheral is not used within the particular project. In most instances, the peripheral use of IO pins will over-ride their GPIO use.

System options

System power management

ISC module

GPIO pins

KBI module

IRQ

TPM module

TPM channels

MTIM module

ADC module

Analog comparator

SCI module

SPI module

IIC module

Most projects are likely to require at least the first four categories.

For an assembly project, a further decision will be whether to use relocatable assembly or absolute assembly. The use of the ORG directive would indicate absolute assembly (although the position of the directive is probably incorrect).

Regards,

Mac

Re: QG8 ASM sample code

admin — Sat, 29 Dec 2007 15:58:49 GMT

Hi Mac,
Thank you for your suggestion.

Do you know what is the standard absolute essential set up routine(code) in order for the program to work? Not including modules for the project and additonal features....

For example, I found this part in the QG8 sample code in code warrior

ldhx   #$25F
txs                       ;Initialize Stack Pointer

I think this initialization would be absolute enssetial for any program to work because I remeber when I was using in HC11 there is a same initialization required which is

stack equ $00c6

lds #stack

Since I am using internal clock source, I would think this would be the absolute essential set up routine required for every program using internal clock source on top of additional module initialization ?

            ldhx   #$25F
            txs                                   ;Initialize Stack Pointer
            lda   #%01000110          ;clock set up
            sta   ICS1
            lda   #%00000000
            sta   ICS2

Thanks!

Re: QG8 ASM sample code

bigmac — Sun, 30 Dec 2007 15:19:57 GMT

Hello,

Yes, I did happen to omit stack initialisation from the previous check list. This is so fundamental, it should be the first thing done on entry to the program, normally to set the stack pointer to "end of RAM". Symbolically, this is done with the following code -

org ROMStart

Startup_:

ldhx #RAMEnd+1

txs

...

Note that the value in the stack pointer will be one less than the H:X value.

A further essential item that was omitted from the check list, to set the reset vector to the start of your code. For an absolute assembly program, the following code should be present at the end of the .asm file -

org Vreset

dc.w Startup_

Of course, if the project requires use of other interrupt vectors, these should also be initialised in a similar manner.

For the following items, you should at least check whether the default register settings meet the specific requirements of the project.

System options:

SOPT1, SOPT2 registers

System power management:

SPMSC1, SPMSC2, SPMSC3 registers

ISC module:

ICS1, ICS2 registers

GPIO pins, port A:

PTAD, PTADD, PTAPE, PTASE, PTADS

GPIO pins, port B:

PTBD,PTBDD,PTBPE, PTBSE, PTBDS

In many instances, the default settings may suffice, but you will need to check anyway. Suitable initialisation of unused GPIO pins is just as important as for the pins that are used by the project, to prevent any input from floating at an indeterminate voltage level.

Regards,

Mac

Re: QG8 ASM sample code

admin — Sun, 30 Dec 2007 17:36:08 GMT

Hi Mac,
Thank you so much for your help to put me on the right track, I can not wait to overcome the elementary initialization procedures in order to make use of the micro.

Can you direct me to the text where it covers the code

org Vreset

dc.w Startup_

I am lost on this particular command

dc.w

Can not find that in the instruction set, so I guess its not an instruction?

Thank you so much for your guidance!
regards,

Message Edited by Learner on 2007-12-30 09:36 AM

Re: QG8 ASM sample code

bigmac — Sun, 30 Dec 2007 19:39:24 GMT

Hello,

Learner wrote:

org Vreset
dc.w Startup_

I am lost on this particular command

dc.w

Can not find that in the instruction set, so I guess its not an instruction?

This is an assembler directive (org is also a directive). It means to "define a constant word" at the current address, i.e. the word value is the address of Startup_ label.

I assumed that you were using CW assembler. If you are using a different assembler, the directives may differ from the ones I have used. The various CW assembler directives can be found in the assembler manual, within the CW installation (possibly ...\Help\pdf\Assembler_HC08.pdf).

Regards,

Mac

Message Edited by bigmac on 2007-12-30 10:41 PM