Microcontroller, 68HC11A1, 68HC11, 68HC811, HC11...
Orgler electronic
"Applications with microcontroller HC11"
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SPI and SCI on PORTD of HC11
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The HC11 sends in every loop (300microsec) the charackter 'S'= 0x53
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******************* SAMPLE SPI SEND PROGRAMM ********
PORTD EQU $1008
DDRD EQU $1009
TFLG1 EQU $1023
TOC3 EQU $101A
SPCR EQU $1028
SPSR EQU $1029
SPDR EQU $102A
BIT5 EQU 00100000B
ORG $E000
START LDS #$00FF
*=============== INIT SPI ====================
ldaa DDRD
oraa #00111000B
staa DDRD set data direction
ldaa #01110011B SPI ON
staa SPCR
**********************************************
SYSTEM_LOOP ldaa #'S'
staa SPDR
wait_spi ldaa SPSR Data transfer finished ?
bpl wait_spi
jsr REALTIME
JMP SYSTEM_LOOP
*-----------------------------------------------------
REALTIME LDAA #BIT5 wait for Real Time
WAIT_REAL BITA TFLG1
BEQ WAIT_REAL
STAA TFLG1 reset TOC3
* ----------------------
LDD TOC3
ADDD #600 300 ęsec
STD TOC3
rts
*-----------------------------------------------
ORG $FFFE
FDB START
*==================================================
External EEPROM connected over SPI with 68HC11
Example program 68HC11 with SPI to external EEPROM
Usage:
set : JSR InitSpi in your INIT-Routine
Set one of the following routines in your loop
JSR LoadFromEEprom
JSR SaveToEEprom
In a Output Compare Interrupt routine with a 200 mikrosec.
period I have the following code:
ldx #$1000 Register Base Address
ldy Spi_Task
jsr Y
The routines are tested with hardware
68hc11 in expanded mode and the BYTERUNNER
*SPI_Address RMB 2
*SPI_TimeOut RMB 1
*SPI_Task RMB 2
*SPI_pointer RMB 2
*SPI_nrbytes RMB 1
*--------------------------------------------
portd EQU $08
spcr EQU $28
spsr EQU $29
spdr EQU $2A
*--------------------------------------------
InitSPI ldaa DDRD
oraa #00111000B
staa DDRD
ldaa #00110011B
staa SPCR
ldaa PORTD
oraa #BIT4+BIT3
staa PORTD
ldd #SPIvoidTask
std SPI_Task
rts
****************************************
SaveToEEprom ldd #0
std SPI_Address
ldaa #64
staa SPI_nrbytes 64 Bytes
ldd #SPI_TEXT_DATA TEXT-BLOCK in EPROM
std SPI_pointer
ldd #SendSPI_Task
std SPI_Task
rts
*------------------------------------------------------------
LoadFromEEprom ldd #0
std SPI_Address
ldaa #64
staa SPI_nrbytes 64 Bytes
ldd #RamAddress
std SPI_pointer
ldd #LoadSPI_Task
std SPI_Task
rts
*------------------------------------------------------------
*************************************************************
* R E A D - T A S K S *
*************************************************************
************** Wait until device is ready
Slave_Busy bclr portd,X,BIT4 Ack - Falling edge
ldd #LoadSPI_Task
std SPI_Task
bset portd,X,BIT4+BIT3
rts
*************************************************************
*************************************************************
LoadSPI_Task bclr portd,X,BIT3 Start=Falling Edge
ldd #SPI__Add0 delay min 5 uSec
std SPI_Task
clr SPI_TimeOut
TURN_ON_SPI bset spcr,X,BIT6 SPI ON !
ldab #10100000B CONTROL-BYTE[write]
stab SPDR
rts
* ------------------------
SPI__Add0 brclr spsr,X,BIT7,spi_rts
bclr spcr,X,11000000B SPI-Off
bset portd,X,BIT4 Ack - Rising edge
ldab PORTD
bitb #BIT2
bne Slave_Busy
ldd #SPI__Add1
std SPI_Task
bclr portd,X,BIT4 Ack - Falling edge
bset spcr,X,BIT6 SPI ON !
ldaa SPI_Address
anda #00011111B
staa SPDR
clr SPI_TimeOut
rts
***************************************
SPI__Add1 brclr spsr,X,BIT7,spi_rts
ldaa SPCR
anda #00111111B SPI-Off
staa SPCR
ldab PORTD
orab #BIT4
stab PORTD Ack - Rising edge
bitb #BIT2
bne nack
ldd #SPI_StartRead
std SPI_Task
bclr portd,X,BIT4 Ack - falling edge
bset spcr,X,BIT6 SPI ON !
ldaa SPI_Address+1
staa SPDR
clr SPI_TimeOut
rts
***************************************
SPI_StartRead brclr spsr,X,BIT7,spi_rts
ldaa SPCR
anda #00111111B SPI-Off
staa SPCR
ldab PORTD
orab #BIT4
stab PORTD Ack - Rising edge
bitb #BIT2
bne nack
bra XXX
spi_rts inc SPI_TimeOut
ldaa SPI_TimeOut
cmpa #100
bls spi__rts
jmp SPI_TIMEOUT
spi__rts rts
XXX orab #BIT3
andb #11101111B Ack - falling edge
stab PORTD
ldx #SPI_ControlRead
stx SPI_Task
orab #BIT4
stab PORTD
rts
************************************************************
SPI_ControlRead bclr portd,X,BIT3 Start=Falling Edge
ldd #SPI_TestRead delay min 5 uSec
std SPI_Task
clr SPI_TimeOut
bset spcr,X,BIT6 SPI ON
ldab #10100001B CONTROL-BYTE[read]
stab SPDR
rts
***************************************
nack ldaa DDRD
oraa #BIT3
staa DDRD
ldd #SPIvoidTask
std SPI_Task
rts
***************************************
SPI_TestRead brclr spsr,X,BIT7,spi_rts RTI
ldaa SPCR
anda #00111111B SPI-Off
staa SPCR
ldab PORTD
orab #BIT4
stab PORTD Ack - Rising edge
bitb #BIT2
bne nack
ldx #SPI_Read
stx SPI_Task
andb #11101111B Ack - falling edge
stab PORTD
oraa #BIT6
staa SPCR SPI-On
ldaa #$FF
staa SPDR
rts
***************************************
SPI_Read brclr spsr,X,BIT7,spi_rts RTI
ldaa SPCR
anda #00111111B SPI-Off
staa SPCR
ldab PORTD
orab #BIT4
stab PORTD Ack - Rising edge
bitb #BIT2
bne nack
clr SPI_TimeOut
ldx SPI_pointer
andb #11101111B Ack - falling edge
stab PORTD
ldab SPDR
stab X
inx
stx SPI_pointer
ldab SPI_nrbytes
decb
ble Read_exit
stab SPI_nrbytes
oraa #BIT6
staa SPCR SPI-On
ldaa #$FF
staa SPDR
rts
***************************************
Read_exit oraa #BIT6
staa SPCR SPI-On
ldd #SPI_EXIT
std SPI_Task
ldaa PORTD
oraa #BIT3
staa PORTD generate NACK
ldaa #$FF
staa SPDR
rts
*************************************************************
SPIvoidTask rts
*************************************************************
* S A V E - T A S K S *
*************************************************************
SendSPI_Task ldaa PORTD
anda #11110111B START Ramp
staa PORTD
ldd #SPI_Add0 delay min 5 uSec
std SPI_Task
clr SPI_TimeOut
ldaa SPCR
oraa #BIT6
staa SPCR SPI On!
ldab #10100000B CONTROL-BYTE[write]
stab SPDR
rts
* ------------------------
SPI_Add0 ldab SPSR
bpl SPI_RTI
ldaa SPCR
anda #00111111B SPI-Off
staa SPCR
ldab PORTD
orab #BIT4
stab PORTD Ack - rising edge
bitb #BIT2
bne SlaveBusy
ldx #SPI_Add1
stx SPI_Task
andb #11101111B Ack - falling edge
stab PORTD
oraa #BIT6
staa SPCR SPI-On
ldaa SPI_Address
anda #00011111B
staa SPDR
clr SPI_TimeOut
rts
************** Wait until device is ready ***********
SlaveBusy andb #11101111B Ack - falling edge
stab PORTD
ldx #SendSPI_Task
stx SPI_Task
orab #BIT4+BIT3 generate STOP Ramp
stab PORTD
rts
*********************************************************
SPI_Add1 ldab SPSR
bpl SPI_RTI
ldaa SPCR
anda #00111111B SPI-Off
staa SPCR
ldab PORTD
orab #BIT4
stab PORTD Ack - rising edge
bitb #BIT2
bne NACK
ldx #SPI_DATwrite
stx SPI_Task
andb #11101111B Ack - Fallflanke
stab PORTD
oraa #BIT6
staa SPCR SPI-On
ldaa SPI_Address+1
staa SPDR
clr SPI_TimeOut
rts
***************************************
SPI_RTI inc SPI_TimeOut
ldaa SPI_TimeOut
cmpa #100
bls SPIweg
jmp SPI_TIMEOUT
SPIweg rts
***************************************
SPI_DATwrite ldab SPSR
bpl SPI_RTI
ldaa SPCR
anda #00111111B SPI-Off
staa SPCR
ldab PORTD
orab #BIT4
stab PORTD Ack - rising edge
bitb #BIT2
bne NACK
ldx SPI_pointer
andb #11101111B Ack - falling edge
stab PORTD
oraa #BIT6
staa SPCR SPI-On
ldaa X
inx
stx SPI_pointer
staa SPDR
ldab SPI_nrbytes
decb
ble SPI_SaveExit 0
stab SPI_nrbytes
rts
**************************************************************
NACK ldx #SPIvoidTask
stx SPI_Task
rts
*************************************************************
SPI_SaveExit ldd #SPI_EXIT
std SPI_Task
clr SPI_TimeOut
rts
*************************************************************
SPI_EXIT ldab SPSR
bpl SPI_RTI
ldaa SPCR
anda #00111111B SPI-Off
staa SPCR
ldab PORTD
orab #BIT4
stab PORTD Ack - rising edge
clr SPI_TimeOut
andb #11101111B Ack - falling edge
stab PORTD
ldx #SPIvoidTask
stx SPI_Task
orab #BIT4+BIT3 STOP Ramp
stab PORTD
rts
*************************************************************
SPI_TIMEOUT ldd #SPIvoidTask
std SPI_Task
rts
*************************************************************