Indirect Addressing?

beardcm · 2005-04-06 03:23

I'm having trouble understanding·what this command in the sendstring2 subroutine really does in relation to the addressing:

mov·w,#STRINGS_ORG>>8

**refer to code above**

beardcm · 2005-04-06 03:26

Sorry, forgot to post the code for the previous message.

Program Code:

SX28AC

TEST1
················································································
SX_Key

; ** Baud Rates for UART 1 **
U1B1200 ;baud rate of 1.2 Kbps

; ** Baud Rates for UART 2· **

U2B9600 ;baud rate of 9.6 kbps

IFDEF SX_Key ;SX-Key Directives

· IFDEF SX28AC ;SX28AC device directives for SX-Key
device SX28,oschs2,turbo,stackx,optionx
· ENDIF

· IFDEF SX48_52 ;SX48/52/BD device directives for SX-Key
device oschs2
· ENDIF
freq 50_000_000

ELSE · ;SASM Directives
·
· IFDEF SX28AC ;SX28AC device directives for SASM
device SX28,oschs2,turbo,stackx,optionx
· ENDIF
·
· IFDEF SX48_52 ;SX48BD or SX52BD device directives for SASM
device SX52,oschs2·
· ENDIF

ENDIF
id '2UART VP' ;
reset resetEntry ; set reset vector

IRC_CAL IRC_FAST

;*********************************************************************************************

;

Macro's

; Macro: _bank
; Sets the bank appropriately for all revisions of SX.
;
; This is required since the bank instruction has only a 3-bit
operand, it cannot be used to
; access all 16 banks of the SX48/52.· FSR.7 (SX48/52bd production
release) needs to be set
; appropriately, depending on the bank address being accessed. This
macro fixes this.
;
; So, instead of using the bank instruction to switch between banks,
use _bank instead.

;*********************************************************************************************

_bank macro 1
· noexpand
bank \1
IFDEF SX48_52
·· IF \1 & %10000000 ;SX48BD and SX52BD (production release) bank
instruction
· expand
setb fsr.7 ;modifies FSR bits 4,5 and 6. FSR.7 needs to be set by
software.
· noexpand
··· ·· ELSE
· expand
clrb fsr.7
· noexpand
········· ENDIF
ENDIF
endm

;*********************************************************************************************
; Macro: _mode
; Sets the MODE register appropriately for all revisions of SX.
;
; This is required since the MODE (or MOV M,#) instruction has only a
4-bit operand.
; The SX28AC use only 4 bits of the MODE register, however the
SX48/52BD have
; the added ability of reading or writing some of the MODE registers,
and therefore use
; 5-bits of the MODE register. The· MOV M,W instruction modifies all
8-bits of the
; MODE register, so this instruction must be used on the SX48/52BD to
make sure the MODE
; register is written with the correct value. This macro fixes this.
;
; So, instead of using the MODE or MOV M,# instructions to load the M
register, use
;· _mode instead.

;*********************************************************************************************

_mode macro 1

· noexpand
IFDEF SX48_52
· expand
mov w,#\1·········· ;loads the M register correctly for the SX48BD
and SX52BD
mov m,w
· noexpand
ELSE
· expand
mov m,#\1··· ;loads the M register correctly for the SX18AC, SX20AC
;and SX28AC
· noexpand
ENDIF

endm

;*********************************************************************************************
······· ; INCP/DECP macros for incrementing/decrementing pointers to
RAM
······· ; used to compensate for incompatibilities between SX28AC and
SX52BD

;*********************************************************************************************

INCP macro 1 ; Increments a pointer to RAM
inc··· \1
IFNDEF SX48_52
setb· \1.4 ; If SX18 or SX28AC,keep bit 4 of the pointer = 1
ENDIF ; to jump from $1f to $30,etc
endm

DECP macro 1 ; Decrements a pointer to RAM
IFDEF SX48_52
dec··· \1
ELSE
clrb·· \1.4 ; If SX18 or SX28AC, forces rollover to next bank
dec··· \1 ; if it rolls over. (skips banks with bit 4 = 0)
setb·· \1.4············ ; Eg: $30 ---> $20 ---> $1f ---> $1f
ENDIF·························· ; AND: $31 ---> $21 ---> $20 ---> $30
endm

;*********************************************************************************************
······· ; Error generating macros
······· ; Used to generate an error message if the label is
intentionally moved into the second page.
······· ; Use for lookup tables.

;*********************************************************************************************

tablestart macro 0 ; Generates an error message if code that MUST be
in
; the first half of a page is moved into the second half
if $ & $100
ERROR····· 'Must be located in the first half of a page.'
endif
endm

tableEnd macro 0 ; Generates an error message if code that MUST be in
; the first half of a page is moved into the second half

if $ & $100
ERROR····· 'Must be located in the first half of a page.'
endif
endm

;*********************************************************************************************
;

Memory Organization

;*********************************************************************************************

;*********************************************************************************************
;

Data Memory address
definitions

; These definitions ensure the proper address is used for banks 0 - 7
for 2K SX devices
; (SX28) and 4K SX devices (SX48/52).
;*********************************************************************************************

IFDEF SX48_52

global_org = $0A
bank0_org = $00
bank1_org = $10
bank2_org = $20
bank3_org = $30
bank4_org = $40
bank5_org = $50
bank6_org = $60
bank7_org = $70

ELSE

global_org = $08
bank0_org = $10
bank1_org = $30
bank2_org = $50
bank3_org = $70
bank4_org = $90
bank5_org = $B0
bank6_org = $D0
bank7_org = $F0

ENDIF

;*********************************************************************************************
;

Global Register
definitions

; NOTE: Global data memory starts at $0A on SX48/52 and $08 on
SX18/20/28.
;*********************************************************************************************

org···· global_org

flags0 equ global_org + 0 ; stores bit-wise operators like flags
; and function-enabling bits (semaphores)
;

VP: RS232
Receive

rs232Tx1Flag equ flags0.0 ;indicates that UART1 is transmitting if set
or not transmitting if reset
rs232Tx2Flag equ flags0.1 ;indicates that UART2 is transmitting if set
or not transmitting if reset
rs232Rx1Flag equ flags0.2 ;indicates that UART1 has received a byte if
set
rs232Rx2Flag equ flags0.3 ;indicates that UART2 has received a byte if
set

isrTemp0 equ global_org + 1 ; Interrupt Service Routine's temp
register.·
; Don't use this register in the mainline.

localTemp0 equ global_org + 2 ; temporary storage register
; Used by first level of nesting
; Never guaranteed to maintain data

localTemp1 equ global_org + 3 ; temporary storage register
; Used by second level of nesting
; or when a routine needs more than one
; temporary global register.

localTemp2 equ global_org + 4 ; temporary storage register
; Used by third level of nesting or by
; main loop routines that need a loop
; counter, etc.

;*********************************************************************************************
;

RAM Bank Register
definitions

;*********************************************************************************************

;*********************************************************************************
; Bank 0

;*********************************************************************************

org···· bank0_org

bank0 = $

;*********************************************************************************
; Bank 1

;*********************************************************************************

org···· bank1_org

bank1 = $
rs232TxBank =······ $ ;UART Transmit bank
rs232Tx1High ds····· 1 ;High Byte to be· transmitted
rs232Tx1Low ds····· 1 ;Low· Byte to be transmitted
rs232Tx1Count ds····· 1 ;counter to keep track of the bits sent
rs232Tx1Divide ds····· 1 ;xmit timing counter
rs232Tx1Byte ds 1 ;store the byte to be sent in this buffer

rs232Tx2High ds····· 1 ;High Byte to be· transmitted
rs232Tx2Low ds····· 1 ;Low· Byte to be transmitted
rs232Tx2Count ds····· 1 ;counter to keep track of the bits sent
rs232Tx2Divide ds····· 1 ;xmit timing counter
rs232Tx2Byte ds 1 ;store the byte to be sent in this buffer

MultiplexBank = $ ;Multipler Bank
isrMultiplex · ds····· 1· ;Used to jump between the ISR Threads when
; an Interrupt occurs

;*********************************************************************************
; Bank 2

;*********************************************************************************

org···· bank2_org

bank2 = $
rs232RxBank = $

rs232Rx1Count ds····· 1 ;counter to keep track of the number of bits
received
rs232Rx1Divide ds····· 1 ;receive timing counter
rs232Rx1Byte ds····· 1 ;buffer for incoming byte
rs232Byte1 ds 1 ;Used by serial routines

rs232Rx2Count ds····· 1 ;counter to keep track of the number of bits
received
rs232Rx2Divide ds····· 1 ;receive timing counter
rs232Rx2Byte ds····· 1 ;buffer for incoming byte
rs232Byte2 ds 1 ;used by serial routines

;*********************************************************************************
; Bank 3

;*********************************************************************************

org···· bank3_org

bank3 = $

;*********************************************************************************
; Bank 4

;*********************************************************************************

org···· bank4_org

bank4 = $

;*********************************************************************************
; Bank 5

;*********************************************************************************

org···· bank5_org

bank5 = $

;*********************************************************************************
; Bank 6

;*********************************************************************************

org···· bank6_org

bank6 = $

;*********************************************************************************
; Bank 7

;*********************************************************************************

org···· bank7_org

bank7 = $

IFDEF SX48_52

;*********************************************************************************
; Bank 8

;*********************************************************************************

org $80 ;bank 8 address on SX52

bank8 = $

;*********************************************************************************
; Bank 9

;*********************************************************************************

org $90 ;bank 9 address on SX52

bank9 = $

;*********************************************************************************
; Bank A

;*********************************************************************************

org $A0 ;bank A address on SX52

bankA = $

;*********************************************************************************
; Bank B

;*********************************************************************************

org $B0 ;bank B address on SX52

bankB = $

;*********************************************************************************
; Bank C

;*********************************************************************************

org $C0 ;bank C address on SX52

bankC = $

;*********************************************************************************
; Bank D

;*********************************************************************************

org $D0 ;bank D address on SX52

bankD = $

;*********************************************************************************
; Bank E

;*********************************************************************************

org $E0 ;bank E address on SX52

bankE = $

;*********************************************************************************
; Bank F

;*********************************************************************************

org $F0 ;bank F address on SX52

bankF = $

ENDIF

;*****************************************************************************************
;

Port Assignment

;*****************************************************************************************

RA_latch equ %00000000 ;SX28/48/52 port A latch init ;intial value
after reset
RA_DDIR equ %11111111 ;SX28/48/52 port A DDIR value ;0=Output,1=Input
RA_LVL equ %00000000 ;SX28/48/52 port A LVL value ;0=CMOS,1=TTL
RA_PLP equ %00000000 ;SX28/48/52 port A PLP value ;0=Enable,1=Disable

RB_latch equ %10001000 ;SX28/48/52 port B latch init ;intial value
after reset
RB_DDIR equ %01110111 ;SX28/48/52 port B DDIR value ;0=Output,1=Input
RB_ST equ %11111111 ;SX28/48/52 port B ST value ;0=Enable,1=Disable
RB_LVL equ %00000000 ;SX28/48/52 port B LVL value ;0=CMOS,1=TTL
RB_PLP equ %11001100 ;SX28/48/52 port B PLP value ;0=Enable,1=Disable

RC_latch equ %00000000 ;SX28/48/52 port C latch init ;intial value
after reset
RC_DDIR equ %11111111 ;SX28/48/52 port C DDIR value ;0=Output,1=Input
RC_ST equ %11111111 ;SX28/48/52 port C ST value ;0=Enable,1=Disable
RC_LVL equ %00000000 ;SX28/48/52 port C LVL value ;0=CMOS,1=TTL
RC_PLP equ %00000000 ;SX28/48/52 port C PLP value ;0=Enable,1=Disable

IFDEF SX48_52

RD_latch equ %00000000 ;SX48/52 port D latch init ;intial value after
reset
RD_DDIR equ %11111111 ;SX48/52 port D DDIR value ;0=Output,1=Input
RD_ST equ %11111111 ;SX48/52 port D ST value ;0=Enable,1=Disable
RD_LVL equ %00000000 ;SX48/52 port D LVL value ;0=CMOS,1=TTL
RD_PLP equ %00000000 ;SX48/52 port D PLP value ;0=Enable,1=Disable

RE_latch equ %00000000 ;SX48/52 port E latch init ;intial value after
reset
RE_DDIR equ %11111111 ;SX48/52 port E DDIR value ;0=Output,1=Input
RE_ST equ %11111111 ;SX48/52 port E ST value ;0=Enable,1=Disable
RE_LVL equ %00000000 ;SX48/52 port E LVL value ;0=CMOS,1=TTL
RE_PLP equ %00000000 ;SX48/52 port E PLP value ;0=Enable,1=Disable

ENDIF

;*********************************************************************************************
;

Pin Definitions

;*********************************************************************************************

rs232Rxpin1····· equ···· rb.6 ;UART1 receive input
rs232Txpin1····· equ···· rb.7 ;UART1 transmit output

rs232Rxpin2····· equ···· rb.2 ;UART2 receive input
rs232Txpin2····· equ···· rb.3 ;UART2 transmit output

;*********************************************************************************************
;

Program constants

;*********************************************************************************************

;*********************************************************************************************
; UART Constants values
;*********************************************************************************************

intPeriod = 217

UARTfs = 230400

Num = 4 ; Number of times ISR thread1 is called in the
; ISRMultiplexer
IFDEF· U1B1200
UARTBaud1 = 1200
ENDIF

IFDEF· U1B2400
UARTBaud1 = 2400
ENDIF

IFDEF· U1B4800
UARTBaud1 = 4800
ENDIF

IFDEF· U1B9600
UARTBaud1 = 9600
ENDIF

IFDEF· U1B1920
UARTBaud1 = 19200
ENDIF

IFDEF· U1B5760
UARTBaud1 = 57600
ENDIF

UARTDivide1 = (UARTfs/(UARTBaud1*Num)) ;48
UARTStDelay1 = UARTDivide1 +(UARTDivide1/2)+1

IFDEF· U2B1200
UARTBaud2 = 1200
ENDIF

IFDEF· U2B2400
UARTBaud2 = 2400
ENDIF

IFDEF· U2B4800
UARTBaud2 = 4800
ENDIF

IFDEF· U2B9600
UARTBaud2 = 9600
ENDIF

IFDEF· U2B1920
UARTBaud2 = 19200
ENDIF

IFDEF· U2B5760
UARTBaud2 = 57600
ENDIF

UARTDivide2 = (UARTfs/(UARTBaud2*Num)) ;6
UARTStDelay2 = UARTDivide2 +(UARTDivide2/2)+1

IFDEF SX48_52

;*********************************************************************************************
; SX48BD/52BD Mode addresses
; *On SX48BD/52BD, most registers addressed via mode are read and
write, with the
; exception of CMP and WKPND which do an exchange with W.
;*********************************************************************************************
;

Timer (read) addresses

TCPL_R equ $00 ;Read Timer Capture register low byte
TCPH_R equ $01 ;Read Timer Capture register high byte
TR2CML_R equ $02 ;Read Timer R2 low byte
TR2CMH_R equ $03 ;Read Timer R2 high byte
TR1CML_R equ $04 ;Read Timer R1 low byte
TR1CMH_R equ $05 ;Read Timer R1 high byte
TCNTB_R equ $06 ;Read Timer control register B
TCNTA_R equ $07 ;Read Timer control register A

;

Exchange addresses

CMP equ $08 ;Exchange Comparator enable/status register with W
WKPND equ $09 ;Exchange MIWU/RB Interrupts pending with W

;

Port setup (read)
addresses

WKED_R equ $0A ;Read MIWU/RB Interrupt edge setup, 1 = falling, 0 =
rising
WKEN_R equ $0B ;Read MIWU/RB Interrupt edge setup, 0 = enabled, 1 =
disabled
ST_R equ $0C ;Read Port Schmitt Trigger setup, 0 = enabled, 1 =
disabled
LVL_R equ $0D ;Read Port Schmitt Trigger setup, 0 = enabled, 1 =
disabled
PLP_R equ $0E ;Read Port Schmitt Trigger setup, 0 = enabled, 1 =
disabled
DDIR_R equ $0F ;Read Port Direction

;

Timer (write)
addresses

CLR_TMR equ $10 ;Resets 16-bit Timer
TR2CML_W equ $12 ;Write Timer R2 low byte
TR2CMH_W equ $13 ;Write Timer R2 high byte
TR1CML_W equ $14 ;Write Timer R1 low byte
TR1CMH_W equ $15 ;Write Timer R1 high byte
TCNTB_W equ $16 ;Write Timer control register B
TCNTA_W equ $17 ;Write Timer control register A

;

Port setup (write)
addresses

WKED_W equ $1A ;Write MIWU/RB Interrupt edge setup, 1 = falling, 0 =
rising
WKEN_W equ $1B ;Write MIWU/RB Interrupt edge setup, 0 = enabled, 1 =
disabled
ST_W equ $1C ;Write Port Schmitt Trigger setup, 0 = enabled, 1 =
disabled
LVL_W equ $1D ;Write Port Schmitt Trigger setup, 0 = enabled, 1 =
disabled
PLP_W equ $1E ;Write Port Schmitt Trigger setup, 0 = enabled, 1 =
disabled
DDIR_W equ $1F ;Write Port Direction

ELSE

;*********************************************************************************************
; SX28AC Mode addresses
; *On SX28, all registers addressed via mode are write only, with the
exception of
; CMP and WKPND which do an exchange with W.
;*********************************************************************************************

;

Exchange
addresses

CMP equ $08 ;Exchange Comparator enable/status register with W
WKPND equ $09 ;Exchange MIWU/RB Interrupts pending with W

;

Port setup (read)
addresses

WKED_W equ $0A ;Write MIWU/RB Interrupt edge setup, 1 = falling, 0 =
rising
WKEN_W equ $0B ;Write MIWU/RB Interrupt edge setup, 0 = enabled, 1 =
disabled
ST_W equ $0C ;Write Port Schmitt Trigger setup, 0 = enabled, 1 =
disabled
LVL_W equ $0D ;Write Port Schmitt Trigger setup, 0 = enabled, 1 =
disabled
PLP_W equ $0E ;Write Port Schmitt Trigger setup, 0 = enabled, 1 =
disabled
DDIR_W equ $0F ;Write Port Direction

ENDIF

;*********************************************************************************************
;

Program memory ORG defines

;*********************************************************************************************

INTERRUPT_ORG equ $0 ; Interrupt must always start at location zero
RESETENTRY_ORG equ $1FB ; The program will jump here on reset
SUBROUTINES_ORG equ $200 ; The subroutines are in this location
STRINGS_ORG equ $300 ; The strings are in the location $300
PAGE3_ORG equ $400 ; Page 3 is empty
MAINPROGRAM_ORG equ $600 ; The main program is in the lastpage of
program memory

;*********************************************************************************************
org INTERRUPT_ORG······· ; First location in program memory.
;*********************************************************************************************

;*********************************************************************************************
;

Interrupt Service Routine

; Note 1: The interrupt code must always originate at address $0.
; · Interrupt Frequency = (Cycle Frequency / -(retiw value))·
; · For example: With a retiw value of -217 and an oscillator frequency
; · of 50MHz, this code runs every 4.32us.
; Note 2: Mode Register 'M' is not saved in SX 28 but saved in SX 52
when an Interrupt
; · occurs. If the code is to run on a SX 28 and 'M' register is used
in the ISR,
; · then the 'M' register has to be saved at the Start of ISR and
restored at the
; · End of ISR.
;*********************************************************************************************
org···· $0
interrupt ;3

;*********************************************************************************************
; Interrupt
; Interrupt Frequency = (Cycle Frequency / -(retiw value))· For
example:
; With a retiw value of -217 and an oscillator frequency of 50MHz, this
code runs
; every 4.32us.
;*********************************************************************************************

;*********************************************************************************************
;

VP:VP
Multitasker

; Virtual Peripheral Multitasker : up to 16 individual threads, each
running at the
; (interrupt rate/16). Change them below:
;Input variable(s): isrmultiplex: variable used to choose threads
;Output variable(s): None,executes the next thread
;Variable(s) affected: isrmultiplex
;Flag(s) affected: None
;Program Cycles: 9 cycles (turbo mode)
;*********************************************************************************************

··············· _bank········· Multiplexbank······· ;
··············· inc··········· isrMultiplex········ ; toggle interrupt
rate
··············· mov··········· w,isrMultiplex······ ;

;*********************************************************************************************
; The code between the tableStart and tableEnd statements MUST be
completely within the first
; half of a page. The routines it is jumping to must be in the same
page as this table.
;*********************************************************************************************

········ tableStart································ ; Start all tables
with this macro
··············· jmp··········· pc+w················ ;
··············· jmp··········· isrThread1·········· ;
··············· jmp··········· isrThread2·········· ;
··············· jmp··········· isrThread3·········· ;·
··············· jmp··········· isrThread4·········· ;
··············· jmp··········· isrThread1·········· ;
··············· jmp··········· isrThread5·········· ;
··············· jmp··········· isrThread6·········· ;·
··············· jmp··········· isrThread7·········· ;
··············· jmp··········· isrThread1·········· ;
··············· jmp··········· isrThread8·········· ;
··············· jmp··········· isrThread9·········· ;
··············· jmp··········· isrThread10········· ;·
··············· jmp··········· isrThread1·········· ;
··············· jmp··········· isrThread11········· ;
··············· jmp··········· isrThread12········· ;
··············· jmp··········· isrThread13········· ;
········ tableEnd·································· ; End all tables
with this macro.··

;*********************************************************************************************
;VP: VP Multitasker
; ISR TASKS
;*********************************************************************************************

isrThread1········································· ; Serviced at ISR
rate/4

;*********************************************************************************************
; Virtual Peripheral: Universal Asynchronous Receiver Transmitter
(UART) These routines send
; and receive RS232 serial data, and are currently configured (though
modifications can be
; made) for the popular "No parity-checking, 8 data bit, 1 stop bit"
(N,8,1) data format.
;
; The VP below has 2 UARTS implemented - UART1 & UART2. Both the UARTs
can work at independent
; Baud Rates.
;
; RECEIVING: The rs232Rx1flag & rs232Rx2flag are set high whenever a
valid byte of data has
; been received and it is the calling routine's responsibility to reset
this flag once the
; incoming data has been collected.
;
; TRANSMITTING: The transmit routine requires the data to be inverted
and loaded
; (rs232Txhigh+rs232Txlow) register pair (with the inverted 8 data bits
stored in
; rs232Txhigh and rs232Txlow bit 7 set high to act as a start bit).
Then the number of bits
; ready for transmission (10=1 start + 8 data + 1 stop) must be loaded
into the rs232Txcount
; register. As soon as this latter is done, the transmit routine
immediately begins sending
; the data. This routine has a varying execution rate and therefore
should always be
; placed after any timing-critical virtual peripherals such as timers,
; adcs, pwms, etc.
; Note: The transmit and receive routines are independent and either
may be removed for each
; of the UARTs. The initial "_bank rs232TxBank" & "_bank rs232RxBank"
(common)
; instruction is kept for Transmit & Receive routines.
;······ Input variable(s) : rs232Tx1Low (only high bit used),
rs232Tx1High, rs232Tx1Count
; If rs232Tx1Flag SET, then transmit on UART1
; rs232Tx2Low (only high bit used), rs232Tx2High, rs232Tx2Count
; If rs232Tx2Flag SET, then transmit on UART2
;······ Output variable(s) : rs232Rx1Flag, rs232Rx1Byte
; rs232Rx2Flag, rs232Rx2Byte
;······ Variable(s) affected : rs232Tx1Divide, rs232Rx1Divide,
rs232Rx1Count
; rs232Tx2Divide, rs232Rx2Divide, rs232Rx2Count
;······ Flag(s) affected : rs232Tx1Flag, rs232Tx2Flag
; rs232Rx1Flag, rs232Rx1Flag
; Program cycles: 22 worst case for Tx, 23 worst case for Rx
; Variable Length?· Yes.
;*********************************************************************************************
UART1
rs232Transmit
_bank rs232TxBank ;2 switch to serial register bank

sb rs232Tx1FLag ;1
jmp rs232Receive1 ;1
decsz rs232Tx1Divide ;1 only execute the transmit routine
jmp rs232Receive1 ;1
mov w,#UARTDivide1 ;1 load UART1 baud rate (50MHz)
mov rs232Tx1Divide,w ;1·
test··· rs232Tx1Count ;1 are we sending?
snz ;1·
jmp rs232Receive1 ;1

:txbit clc···························· ;1 yes, ready stop bit
rr····· rs232Tx1High ;1· and shift to next bit
rr····· rs232Tx1Low ;1·
dec···· rs232Tx1Count ;1 decrement bit counter
snb rs232Tx1Low.6 ;1 output next bit
clrb rs232TxPin1 ;1·
sb rs232Tx1Low.6 ;1·
setb rs232TxPin1 ;1·
test··· rs232Tx1Count ;1 are we sending?
snz ;1·
clrb rs232Tx1Flag ;1,22

rs232Receive1
_bank rs232RxBank ;2
······· sb rs232RxPin1 ;1 get current rx bit
······· clc ;1·
······· snb rs232RxPin1 ;1·
······· stc ;1·
test··· rs232Rx1Count·········· ;1 currently receiving byte?
sz ;1·
jmp :rxbit················· ;1 if so, jump ahead
mov···· w,#9··················· ;1 in case start, ready 9 bits

mov···· rs232Rx1Count,w ;1 it is, so renew bit count
mov···· w,#UARTStDelay1 ;1 ready 1.5 bit periods (50MHz)
mov···· rs232Rx1Divide,w ;1·
:rxbit········· decsz rs232Rx1Divide ;1 middle of next bit?
········· jmp :rs232RxOut1 ;1
mov w,#UARTDivide1 ;1 yes, ready 1 bit period (50MHz)
mov rs232Rx1Divide,w ;1·
dec···· rs232Rx1Count·········· ;1 last bit?
sz····························· ;1 if not
rr····· rs232Rx1Byte··········· ;1· then save bit
snz···························· ;1 if so,
setb··· rs232Rx1Flag·········· ;1,23· then set flag
:rs232RxOut1

UART2
_bank rs232TxBank ;2 switch to serial register bank
sb rs232Tx2flag ;1
jmp rs232Receive2 ;1
decsz rs232Tx2Divide ;1 only execute the transmit routine
jmp rs232Receive2 ;1
mov w,#UARTDivide2 ;1 load UART2 baud rate (50MHz)
mov rs232Tx2Divide,w ;1·
test··· rs232Tx2Count ;1 are we sending?
snz ;1
jmp rs232Receive2 ;1

:txbit stc···························· ;1 yes, ready stop bit
rr····· rs232Tx2High ;1· and shift to next bit
rr····· rs232Tx2Low ;1·
dec···· rs232Tx2Count ;1 decrement bit counter
snb rs232Tx2Low.6 ;1 output next bit
clrb rs232TxPin2 ;1·
sb rs232Tx2Low.6 ;1·
setb rs232TxPin2 ;1·
test··· rs232Tx2Count ;1 are we sending?
snz ;1·
clrb rs232Tx2Flag ;1,22

rs232Receive2
_bank rs232RxBank ;2
······· sb rs232RxPin2 ;1 get current rx bit
······· clc ;1·
······· snb rs232RxPin2 ;1·
······· stc ;1·
test··· rs232Rx2Count·········· ;1 currently receiving byte?
sz ;1·
jmp :rxbit················· ;1 if so, jump ahead
mov···· w,#9··················· ;1 in case start, ready 9 bits
sc ;1 skip ahead if not start bit
mov···· rs232Rx2Count,w ;1 it is, so renew bit count
mov···· w,#UARTStDelay2 ;1 ready 1.5 bit periods (50MHz)
mov···· rs232Rx2Divide,w ;1·
:rxbit········· decsz rs232Rx2Divide ;1 middle of next bit?
········· jmp :rs232RxOut2 ;1
mov w,#UARTDivide2 ;1 yes, ready 1 bit period (50MHz)
mov rs232Rx2Divide,w ;1·
dec···· rs232Rx2Count·········· ;1 last bit?
sz····························· ;1 if not
rr····· rs232Rx2Byte··········· ;1· then save bit
snz···························· ;1 if so,
setb··· rs232Rx2Flag·········· ;1,23· then set flag
:rs232RxOut2

UARTOut

;*********************************************************************************************
;===================================== PUT YOUR OWN VPs
HERE==================================
; Virtual Peripheral:
;
; Input variable(s):
; Output variable(s):
; Variable(s) affected:
; Flag(s) affected:
;*********************************************************************************************
;