Author Topic: 9S08PA16 continually resetting - config problem?  (Read 515 times)

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Offline Circlotron

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9S08PA16 continually resetting - config problem?
« on: April 14, 2019, 11:38:09 am »
Trying to get my first bit of .asm code running on a 9S08PA16. Kinda getting there. Currently it's just a loop flashing a LED.  :-[ . The thing is, the reset pin continually pulses low for 4uS every 7.07mS. Running off a 20MHz xtal. Interrupt bit is set, timer is stopped. Watchdog timer is stopped. LVD disabled. Just thinking something is timing out somewhere. There is just a ridiculous amount of config registers in this thing...
 

Offline jaromir

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Re: 9S08PA16 continually resetting - config problem?
« Reply #1 on: April 14, 2019, 02:05:20 pm »
I believe the watchdog is still running.
Show us the code. At least the hardware initialization portion, but since it's just LED flasher, probably whole source code will be OK, too.
 

Offline Circlotron

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Re: 9S08PA16 continually resetting - config problem?
« Reply #2 on: April 14, 2019, 02:16:33 pm »
Okay, here it is. Tabs spaces are being a bit silly...

Code: [Select]
*****************************************
$BASE 10T

PORTA               EQU     $00
PORTAIE EQU $30B8
PORTAOE EQU $30B0

PORTB               EQU     $01
PORTBIE EQU $30B9
PORTBOE EQU $30B1

PORTC            EQU     $02
PORTCIE EQU $30BA
PORTCOE EQU $30B2

PORTD               EQU     $03
PORTDIE EQU $30BB
PORTDOE EQU $30B3

PORTE               EQU     $04
PORTEIE EQU $30BC
PORTEOE EQU $30B4





ADC_SC1 EQU $10 ;Status and Control Register 1 page 466
ADC_SC2 EQU $11 ;Status and Control Register 2
ADC_SC3 EQU $12 ;Status and Control Register 3
ADC_SC4 EQU $13 ;Status and Control Register 4
ADC_RH EQU $14 ;Conversion Result High Register
ADC_RL EQU $15 ;Conversion Result Low Register
ADC_CVH EQU $16 ;Compare Value High Register
ADC_CVL EQU $17 ;Compare Value Low Register
ADC_APCTL1 EQU $30AC ;Pin Control 1 Register
ADC_APCTL2 EQU $30AD ;Pin Control 2 Register

WDOG_CS1 EQU $3030 ;Watchdog Control and Status Register 1 page 517

TSC         EQU $20 ;page
TCNTH EQU $21 ;page
TCNTL EQU $22 ;page
TMODH EQU $23 ;page
TMODL EQU $24 ;page
TSC0         EQU $25 ;page 277
TCH0H EQU $26 ;page 280
TCH0L EQU $27 ;page 281
TSC1         EQU $28 ;page 277
TCH1H EQU $29 ;page
TCH1L EQU $2A ;page
ACMP EQU $2C ;page 499 analog comparator S/C

;internal clock sources
ICS_C1 EQU $3038 ;ICS Control Register 1 page 191
ICS_C2 EQU $3039 ;ICS Control Register 2 page 192
ICS_C3 EQU $303A ;ICS Control Register 3 page 193
ICS_C4 EQU $303B ;ICS Control Register 4 page 193
ICS_S EQU $303C ;ICS Status Register   page 194
ICS_OSCSC EQU $303E ;OSC Status and Control page 195

PMC_SPMSC1 EQU $3040 ;sys pwr management page 52

;VectorStart        EQU     $FFB0 ;page 56
**********************************
;2048 bytes RAM starts at $0040
EXAMPLE_MSB     EQU     $40 ;example
********************************************************************************
TRST         EQU 4 ;timer reset
TSTOP EQU 5 ;timer stop
TOF         EQU 7 ;timer overflow
********************************************************************************
                ORG     $C000 ; <--- new flash start

START BSET TSTOP,TSC ;stop timer
                SEI                      ;no interrupts
LDA #%00000000
STA WDOG_CS1 ;watchdog timer off, bit 7

;set or clear outputs before changing any DDR bits to 1

MOV     #%00000000,PORTA
MOV     #%00000000,PORTB ;
MOV     #%00000000,PORTD

;DDRs
LDA #%00000000
STA PORTAIE
LDA #%00000000
STA PORTAOE
LDA #%00000000
STA PORTBIE
LDA #%00000000
STA PORTBOE
LDA #%00000000
STA PORTCIE
LDA #%00000000
STA PORTCOE
LDA #%00000000
STA PORTDIE
LDA #%00000001
STA PORTDOE
;LDA #%00000000
;STA PORTEIE
;LDA #%00000000
;STA PORTEOE

LDA #$96 ; = #10010110
STA ICS_OSCSC

LDA #$80 ; = #10000000 BDIV = 0, prescaler = 1
STA ICS_C1

LDA #$00
STA ICS_C2

LDA #$00
STA PMC_SPMSC1

                CLC
RSP
                CLRX
                CLRA
*******************************************************************************
TOP BSET 0,PORTD ;LED on
LDHX #1000 ;1000 = 400uS

TOPLOOP AIX #-1 ;2 8 cyc
CPHX #0 ;3 400nS per loop, 2.5MHz
BNE TOPLOOP ;3 400nS/8 = 50nS per cyc @ 20 meg xtal
;  buss = xtal

BCLR 0,PORTD ;LED off
LDHX #1000

BOTLOOP AIX #-1
CPHX #0
BNE BOTLOOP

JMP TOP
*******************************************************************************
                ORG     $FFFE ;Reset
                FDB     START
*******************************************************************************
 

Offline Circlotron

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Re: 9S08PA16 continually resetting - config problem?
« Reply #3 on: April 14, 2019, 02:32:10 pm »
Actually the LED is somewhat more than flashing. With the current code it is 400uS on, 400uS off, but a bit jittery because of the constant resets.
 

Offline jaromir

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Re: 9S08PA16 continually resetting - config problem?
« Reply #4 on: April 14, 2019, 03:13:36 pm »
Manipulating the watchdog is a bit more complicated than just writing to WDOG_CS1 straight.
Take a look at section 21.3.2 of reference manual https://www.nxp.com/docs/en/reference-manual/MC9S08PA16RM_Rev.1.pdf Watchdog is enabled after POR, to reconfigure it, all watchdog registers - except of CNTH/CNTL - must be written.

This is how I disable the watchdog - in C, but you get the idea -
Code: [Select]
    WDOG_TOVALL = 0x00;
    WDOG_TOVALH = 0x10;
    WDOG_CS2 = 0x01;
    WDOG_CS1 = 0x20;
 

Offline Circlotron

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Re: 9S08PA16 continually resetting - config problem?
« Reply #5 on: April 15, 2019, 02:01:32 am »
jaromir, you da man!  :-+

It says there "The new configuration takes effect only after *all* registers except WDOG_CNTH:L are written once after reset. Otherwise, the WDOG uses the reset values by default.

So I put the following and it works. I'm sure there will be other questions as I proceed.

Code: [Select]
;For watchdog setting to take effect, all regs must be written to
;even if it the same as their default reset values!!!
 
LDA #$20
STA WDOG_CS1 ;watchdog timer off
LDA $01
STA WDOG_CS2
LDA #$10
STA WDOG_TOVALH
LDA #$00
STA WDOG_TOVALl
 


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