mirror of
https://github.com/cc65/cc65.git
synced 2024-11-05 08:05:51 +00:00
409 lines
7.9 KiB
ArmAsm
409 lines
7.9 KiB
ArmAsm
;
|
|
; Serial driver for the Atari Lynx ComLynx port.
|
|
;
|
|
; Karri Kaksonen, 17.09.2009
|
|
;
|
|
|
|
.include "lynx.inc"
|
|
.include "zeropage.inc"
|
|
.include "ser-kernel.inc"
|
|
.include "ser-error.inc"
|
|
|
|
; ------------------------------------------------------------------------
|
|
; Header. Includes jump table
|
|
|
|
.segment "JUMPTABLE"
|
|
|
|
; Driver signature
|
|
.byte $73, $65, $72 ; "ser"
|
|
.byte SER_API_VERSION ; Serial API version number
|
|
|
|
; Jump table.
|
|
.addr INSTALL
|
|
.addr UNINSTALL
|
|
.addr OPEN
|
|
.addr CLOSE
|
|
.addr GET
|
|
.addr PUT
|
|
.addr STATUS
|
|
.addr IOCTL
|
|
.addr IRQ
|
|
|
|
;----------------------------------------------------------------------------
|
|
; Global variables
|
|
;
|
|
|
|
.bss
|
|
|
|
TxBuffer: .res 256
|
|
RxBuffer: .res 256
|
|
RxPtrIn: .res 1
|
|
RxPtrOut: .res 1
|
|
TxPtrIn: .res 1
|
|
TxPtrOut: .res 1
|
|
contrl: .res 1
|
|
SerialStat: .res 1
|
|
TxDone: .res 1
|
|
|
|
.code
|
|
|
|
;----------------------------------------------------------------------------
|
|
; INSTALL: Is called after the driver is loaded into memory.
|
|
;
|
|
; Must return an SER_ERR_xx code in a/x.
|
|
|
|
INSTALL:
|
|
; Set up IRQ vector ?
|
|
|
|
;----------------------------------------------------------------------------
|
|
; UNINSTALL: Is called before the driver is removed from memory.
|
|
; No return code required (the driver is removed from memory on return).
|
|
;
|
|
|
|
UNINSTALL:
|
|
|
|
;----------------------------------------------------------------------------
|
|
; CLOSE: Close the port and disable interrupts. Called without parameters.
|
|
; Must return an SER_ERR_xx code in a/x.
|
|
|
|
CLOSE:
|
|
; Disable interrupts
|
|
; Done, return an error code
|
|
lda #<SER_ERR_OK
|
|
ldx #>SER_ERR_OK
|
|
rts
|
|
|
|
;----------------------------------------------------------------------------
|
|
; OPEN: A pointer to a ser_params structure is passed in ptr1.
|
|
;
|
|
; The Lynx has only two correct serial data formats:
|
|
; 8 bits, parity mark, 1 stop bit
|
|
; 8 bits, parity space, 1 stop bit
|
|
;
|
|
; It also has two wrong formats;
|
|
; 8 bits, even parity, 1 stop bit
|
|
; 8 bits, odd parity, 1 stop bit
|
|
;
|
|
; Unfortunately the parity bit includes itself in the calculation making
|
|
; parity not compatible with the rest of the world.
|
|
;
|
|
; We can only specify a few baud rates.
|
|
; Lynx has two non-standard speeds 31250 and 62500 which are
|
|
; frequently used in games.
|
|
;
|
|
; The receiver will always read the parity and report parity errors.
|
|
;
|
|
; Must return an SER_ERR_xx code in a/x.
|
|
|
|
OPEN:
|
|
stz RxPtrIn
|
|
stz RxPtrOut
|
|
stz TxPtrIn
|
|
stz TxPtrOut
|
|
|
|
; clock = 8 * 15625
|
|
lda #%00011000
|
|
sta TIM4CTLA
|
|
ldy #SER_PARAMS::BAUDRATE
|
|
lda (ptr1),y
|
|
|
|
ldx #1
|
|
cmp #SER_BAUD_62500
|
|
beq setbaudrate
|
|
|
|
ldx #2
|
|
cmp #SER_BAUD_31250
|
|
beq setbaudrate
|
|
|
|
ldx #12
|
|
cmp #SER_BAUD_9600
|
|
beq setbaudrate
|
|
|
|
ldx #25
|
|
cmp #SER_BAUD_4800
|
|
beq setbaudrate
|
|
|
|
ldx #51
|
|
cmp #SER_BAUD_2400
|
|
beq setbaudrate
|
|
|
|
ldx #103
|
|
cmp #SER_BAUD_1200
|
|
beq setbaudrate
|
|
|
|
ldx #207
|
|
cmp #SER_BAUD_600
|
|
beq setbaudrate
|
|
|
|
; clock = 6 * 15625
|
|
ldx #%00011010
|
|
stx TIM4CTLA
|
|
|
|
ldx #12
|
|
cmp #SER_BAUD_7200
|
|
beq setbaudrate
|
|
|
|
ldx #25
|
|
cmp #SER_BAUD_3600
|
|
beq setbaudrate
|
|
|
|
ldx #207
|
|
stx TIM4BKUP
|
|
|
|
; clock = 4 * 15625
|
|
ldx #%00011100
|
|
cmp #SER_BAUD_300
|
|
beq setprescaler
|
|
|
|
; clock = 6 * 15625
|
|
ldx #%00011110
|
|
cmp #SER_BAUD_150
|
|
beq setprescaler
|
|
|
|
; clock = 1 * 15625
|
|
ldx #%00011111
|
|
stx TIM4CTLA
|
|
cmp #SER_BAUD_75
|
|
beq baudsuccess
|
|
|
|
ldx #141
|
|
cmp #SER_BAUD_110
|
|
beq setbaudrate
|
|
|
|
; clock = 2 * 15625
|
|
ldx #%00011010
|
|
stx TIM4CTLA
|
|
ldx #68
|
|
cmp #SER_BAUD_1800
|
|
beq setbaudrate
|
|
|
|
; clock = 6 * 15625
|
|
ldx #%00011110
|
|
stx TIM4CTLA
|
|
ldx #231
|
|
cmp #SER_BAUD_134_5
|
|
beq setbaudrate
|
|
|
|
lda #<SER_ERR_BAUD_UNAVAIL
|
|
ldx #>SER_ERR_BAUD_UNAVAIL
|
|
rts
|
|
setprescaler:
|
|
stx TIM4CTLA
|
|
bra baudsuccess
|
|
setbaudrate:
|
|
stx TIM4BKUP
|
|
baudsuccess:
|
|
ldx #TxOpenColl|ParEven
|
|
stx contrl
|
|
ldy #SER_PARAMS::DATABITS ; Databits
|
|
lda (ptr1),y
|
|
cmp #SER_BITS_8
|
|
bne invparameter
|
|
ldy #SER_PARAMS::STOPBITS ; Stopbits
|
|
lda (ptr1),y
|
|
cmp #SER_STOP_1
|
|
bne invparameter
|
|
ldy #SER_PARAMS::PARITY ; Parity
|
|
lda (ptr1),y
|
|
cmp #SER_PAR_NONE
|
|
beq invparameter
|
|
cmp #SER_PAR_MARK
|
|
beq checkhs
|
|
cmp #SER_PAR_SPACE
|
|
bne @L0
|
|
ldx #TxOpenColl
|
|
stx contrl
|
|
bra checkhs
|
|
@L0:
|
|
ldx #TxParEnable|TxOpenColl|ParEven
|
|
stx contrl
|
|
cmp #SER_PAR_EVEN
|
|
beq checkhs
|
|
ldx #TxParEnable|TxOpenColl
|
|
stx contrl
|
|
checkhs:
|
|
ldx contrl
|
|
stx SERCTL
|
|
ldy #SER_PARAMS::HANDSHAKE ; Handshake
|
|
lda (ptr1),y
|
|
cmp #SER_HS_NONE
|
|
bne invparameter
|
|
lda SERDAT
|
|
lda contrl
|
|
ora #RxIntEnable|ResetErr
|
|
sta SERCTL
|
|
lda #<SER_ERR_OK
|
|
ldx #>SER_ERR_OK
|
|
rts
|
|
invparameter:
|
|
lda #<SER_ERR_INIT_FAILED
|
|
ldx #>SER_ERR_INIT_FAILED
|
|
rts
|
|
|
|
;----------------------------------------------------------------------------
|
|
; GET: Will fetch a character from the receive buffer and store it into the
|
|
; variable pointed to by ptr1. If no data is available, SER_ERR_NO_DATA is
|
|
; returned.
|
|
|
|
GET:
|
|
lda RxPtrIn
|
|
cmp RxPtrOut
|
|
bne GetByte
|
|
lda #<SER_ERR_NO_DATA
|
|
ldx #>SER_ERR_NO_DATA
|
|
rts
|
|
GetByte:
|
|
ldy RxPtrOut
|
|
lda RxBuffer,y
|
|
inc RxPtrOut
|
|
ldx #$00
|
|
sta (ptr1,x)
|
|
txa ; Return code = 0
|
|
rts
|
|
|
|
;----------------------------------------------------------------------------
|
|
; PUT: Output character in A.
|
|
; Must return an SER_ERR_xx code in a/x.
|
|
|
|
PUT:
|
|
tax
|
|
lda TxPtrIn
|
|
ina
|
|
cmp TxPtrOut
|
|
bne PutByte
|
|
lda #<SER_ERR_OVERFLOW
|
|
ldx #>SER_ERR_OVERFLOW
|
|
rts
|
|
PutByte:
|
|
ldy TxPtrIn
|
|
txa
|
|
sta TxBuffer,y
|
|
inc TxPtrIn
|
|
|
|
bit TxDone
|
|
bmi @L1
|
|
php
|
|
sei
|
|
lda contrl
|
|
ora #TxIntEnable|ResetErr
|
|
sta SERCTL ; Allow TX-IRQ to hang RX-IRQ
|
|
sta TxDone
|
|
plp
|
|
@L1:
|
|
lda #<SER_ERR_OK
|
|
tax
|
|
rts
|
|
|
|
;----------------------------------------------------------------------------
|
|
; STATUS: Return the status in the variable pointed to by ptr1.
|
|
; Must return an SER_ERR_xx code in a/x.
|
|
|
|
STATUS:
|
|
ldy SerialStat
|
|
ldx #$00
|
|
sta (ptr1,x)
|
|
txa ; Return code = 0
|
|
rts
|
|
|
|
;----------------------------------------------------------------------------
|
|
; IOCTL: Driver defined entry point. The wrapper will pass a pointer to ioctl
|
|
; specific data in ptr1, and the ioctl code in A.
|
|
; Must return an SER_ERR_xx code in a/x.
|
|
|
|
IOCTL:
|
|
lda #<SER_ERR_INV_IOCTL
|
|
ldx #>SER_ERR_INV_IOCTL
|
|
rts
|
|
|
|
;----------------------------------------------------------------------------
|
|
; IRQ: Called from the builtin runtime IRQ handler as a subroutine. All
|
|
; registers are already saved, no parameters are passed, but the carry flag
|
|
; is clear on entry. The routine must return with carry set if the interrupt
|
|
; was handled, otherwise with carry clear.
|
|
;
|
|
; Both the Tx and Rx interrupts are level sensitive instead of edge sensitive.
|
|
; Due to this bug you have to disable the interrupt before clearing it.
|
|
|
|
IRQ:
|
|
lda INTSET ; Poll all pending interrupts
|
|
and #SERIAL_INTERRUPT
|
|
bne @L0
|
|
clc
|
|
rts
|
|
@L0:
|
|
bit TxDone
|
|
bmi @tx_irq ; Transmit in progress
|
|
ldx SERDAT
|
|
lda SERCTL
|
|
and #RxParityErr|RxOverrun|RxFrameErr|RxBreak
|
|
beq @rx_irq
|
|
tsb SerialStat ; Save error condition
|
|
bit #RxBreak
|
|
beq @noBreak
|
|
stz TxPtrIn ; Break received - drop buffers
|
|
stz TxPtrOut
|
|
stz RxPtrIn
|
|
stz RxPtrOut
|
|
@noBreak:
|
|
lda contrl
|
|
ora #RxIntEnable|ResetErr
|
|
sta SERCTL
|
|
lda #$10
|
|
sta INTRST
|
|
bra @IRQexit
|
|
@rx_irq:
|
|
lda contrl
|
|
ora #RxIntEnable|ResetErr
|
|
sta SERCTL
|
|
txa
|
|
ldx RxPtrIn
|
|
sta RxBuffer,x
|
|
txa
|
|
inx
|
|
|
|
@cont0:
|
|
cpx RxPtrOut
|
|
beq @1
|
|
stx RxPtrIn
|
|
lda #SERIAL_INTERRUPT
|
|
sta INTRST
|
|
bra @IRQexit
|
|
|
|
@1:
|
|
sta RxPtrIn
|
|
lda #$80
|
|
tsb SerialStat
|
|
@tx_irq:
|
|
ldx TxPtrOut ; Has all bytes been sent?
|
|
cpx TxPtrIn
|
|
beq @allSent
|
|
|
|
lda TxBuffer,x ; Send next byte
|
|
sta SERDAT
|
|
inc TxPtrOut
|
|
|
|
@exit1:
|
|
lda contrl
|
|
ora #TxIntEnable|ResetErr
|
|
sta SERCTL
|
|
lda #SERIAL_INTERRUPT
|
|
sta INTRST
|
|
bra @IRQexit
|
|
|
|
@allSent:
|
|
lda SERCTL ; All bytes sent
|
|
bit #TxEmpty
|
|
beq @exit1
|
|
bvs @exit1
|
|
stz TxDone
|
|
lda contrl
|
|
ora #RxIntEnable|ResetErr
|
|
sta SERCTL
|
|
|
|
lda #SERIAL_INTERRUPT
|
|
sta INTRST
|
|
@IRQexit:
|
|
clc
|
|
rts
|
|
|