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woz64/hardware/cia.asm
2020-01-20 18:09:18 -08:00

254 lines
16 KiB
NASM

#importonce
#import "../hardware/sid.asm"
.filenamespace Cia
// https://www.c64-wiki.com/wiki/CIA
// ========================================================
// ////// CONSTANTS ///////////////////////////////////////
// ========================================================
// CIA 1
// ========================================================
.label C1PRA = $DC00 // CIA 1 A Register Monitoring/control of the 8 data lines of Port A
// Read/Write: Bit 0..7 keyboard matrix columns
// Read: Joystick Port 2: Bit 0..3 Direction (Left/Right/Up/Down), Bit 4 Fire button. 0 = activated.
// Read: Lightpen: Bit 4 (as fire button), connected also with "/LP" (Pin 9) of the VIC
// Read: Paddles: Bit 2..3 Fire buttons, Bit 6..7 Switch control port 1 (%01=Paddles A) or 2 (%10=Paddles B)
.label C1PRB = $DC01 // Monitoring/control of the 8 data lines of Port B. The lines are used for multiple purposes:
// Read/Write: Bit 0..7 keyboard matrix rows
// Read: Joystick Port 1: Bit 0..3 Direction (Left/Right/Up/Down), Bit 4 Fire button. 0 = activated.
// Read: Bit 6: Timer A: Toggle/Impulse output (see register 14 bit 2)
// Read: Bit 7: Timer B: Toggle/Impulse output (see register 15 bit 2)
.label C1DDRA = $DC02 // Bit X: 0=Input (read only), 1=Output (read and write)
.label C1DDRB = $DC03 // Bit X: 0=Input (read only), 1=Output (read and write)
.label C1TALO = $DC04 // Read: actual value Timer A (Low Byte)
// Writing: Set latch of Timer A (Low Byte)
.label C1TAHI = $DC05 // Read: actual value Timer A (High Byte)
// Writing: Set latch of timer A (High Byte) - if the timer is stopped, the high-byte will automatically be re-set as well
.label C1TBLO = $DC06 // Read: actual value Timer B (Low Byte)
// Writing: Set latch of Timer B (Low Byte)
.label C1TBHI = $DC07 // Read: actual value Timer B (High Byte)
// Writing: Set latch of timer B (High Byte) - if the timer is stopped, the high-byte will automatically be re-set as well
.label C1TOD10THS = $DC08 // Read:
// Bit 0..3: Tenth seconds in BCD-format ($0-$9)
// Bit 4..7: always 0
// Writing:
// Bit 0..3: if CRB-Bit7=0: Set the tenth seconds in BCD-format
// Bit 0..3: if CRB-Bit7=1: Set the tenth seconds of the alarm time in BCD-format
.label C1TODSEC = $DC09 // Bit 0..3: Single seconds in BCD-format ($0-$9)
// Bit 4..6: Ten seconds in BCD-format ($0-$5)
// Bit 7: always 0
.label C1TODMIN = $DC0A // Bit 0..3: Single minutes in BCD-format( $0-$9)
// Bit 4..6: Ten minutes in BCD-format ($0-$5)
// Bit 7: always 0
.label C1TODHR = $DC0B // Bit 0..3: Single hours in BCD-format ($0-$9)
// Bit 4..6: Ten hours in BCD-format ($0-$5)
// Bit 7: Differentiation AM/PM, 0=AM, 1=PM
// Writing into this register stops TOD, until register 8 (TOD 10THS) will be read.
.label C1TSDR = $DC0C // The byte within this register will be shifted bitwise to or from the SP-pin with every positive slope at the CNT-pin.
.label C1ICR = $DC0D // CIA1 is connected to the IRQ-Line.
// Read: (Bit0..4 = INT DATA, Origin of the interrupt)
// Bit 0: 1 = Underflow Timer A
// Bit 1: 1 = Underflow Timer B
// Bit 2: 1 = Time of day and alarm time is equal
// Bit 3: 1 = SDR full or empty, so full byte was transferred, depending of operating mode serial bus
// Bit 4: 1 = IRQ Signal occured at FLAG-pin (cassette port Data input, serial bus SRQ IN)
// Bit 5..6: always 0
// Bit 7: 1 = IRQ An interrupt occured, so at least one bit of INT MASK and INT DATA is set in both registers.
// Flags will be cleared after reading the register!
// Write: (Bit 0..4 = INT MASK, Interrupt mask)
// Bit 0: 1 = Interrupt release through timer A underflow
// Bit 1: 1 = Interrupt release through timer B underflow
// Bit 2: 1 = Interrupt release if clock=alarmtime
// Bit 3: 1 = Interrupt release if a complete byte has been received/sent.
// Bit 4: 1 = Interrupt release if a positive slope occurs at the FLAG-Pin.
// Bit 5..6: unused
// Bit 7: Source bit. 0 = set bits 0..4 are clearing the according mask bit. 1 = set bits 0..4 are setting the according mask bit. If all bits 0..4 are cleared, there will be no change to the mask.
.label C1CRA = $DC0E // Control Timer A
// Bit 0: 0 = Stop timer; 1 = Start timer
// Bit 1: 1 = Indicates a timer underflow at port B in bit 6.
// Bit 2: 0 = Through a timer overflow, bit 6 of port B will get high for one cycle , 1 = Through a timer underflow, bit 6 of port B will be inverted
// Bit 3: 0 = Timer-restart after underflow (latch will be reloaded), 1 = Timer stops after underflow.
// Bit 4: 1 = Load latch into the timer once.
// Bit 5: 0 = Timer counts system cycles, 1 = Timer counts positive slope at CNT-pin
// Bit 6: Direction of the serial shift register, 0 = SP-pin is input (read), 1 = SP-pin is output (write)
// Bit 7: Real Time Clock, 0 = 60 Hz, 1 = 50 Hz
.label C1CRB = $DC0F // Control Timer B
// Bit 0: 0 = Stop timer; 1 = Start timer
// Bit 1: 1 = Indicates a timer underflow at port B in bit 7.
// Bit 2: 0 = Through a timer overflow, bit 7 of port B will get high for one cycle , 1 = Through a timer underflow, bit 7 of port B will be inverted
// Bit 3: 0 = Timer-restart after underflow (latch will be reloaded), 1 = Timer stops after underflow.
// Bit 4: 1 = Load latch into the timer once.
// Bit 5..6:
// %00 = Timer counts System cycle
// %01 = Timer counts positive slope on CNT-pin
// %10 = Timer counts underflow of timer A
// %11 = Timer counts underflow of timer A if the CNT-pin is high
// Bit 7: 0 = Writing into the TOD register sets the clock time, 1 = Writing into the TOD register sets the alarm time.
// CIA 2
// ========================================================
.label C2PRA = $DD00 // CIA 2 A Register Monitoring/control of the 8 data lines of Port A
// Bit 0..1: Select the position of the VIC-memory
// %00, 0: Bank 3: $C000-$FFFF, 49152-65535
// %01, 1: Bank 2: $8000-$BFFF, 32768-49151
// %10, 2: Bank 1: $4000-$7FFF, 16384-32767
// %11, 3: Bank 0: $0000-$3FFF, 0-16383 (standard)
// Bit 2: RS-232: TXD Output, userport: Data PA 2 (pin M)
// Bit 3..5: serial bus Output (0=High/Inactive, 1=Low/Active)
// Bit 3: ATN OUT
// Bit 4: CLOCK OUT
// Bit 5: DATA OUT
// Bit 6..7: serial bus Input (0=Low/Active, 1=High/Inactive)
// Bit 6: CLOCK IN
// Bit 7: DATA IN
.label C2PRB = $DD01 // Monitoring/control of the 8 data lines of Port B. The lines are used for multiple purposes:
// Bit 0..7: userport Data PB 0-7 (Pins C,D,E,F,H,J,K,L)
// The KERNAL offers several RS232-Routines, which use the pins as followed:
// Bit 0, 3..7: RS-232: reading
// Bit 0: RXD
// Bit 3: RI
// Bit 4: DCD
// Bit 5: User port pin J
// Bit 6: CTS
// Bit 7: DSR
// Bit 1..5: RS-232: writing
// Bit 1: RTS
// Bit 2: DTR
// Bit 3: RI
// Bit 4: DCD
// Bit 5: User port pin J
.label C2DDRA = $DD02 // Bit X: 0=Input (read only), 1=Output (read and write)
.label C2DDRB = $DD03 // Bit X: 0=Input (read only), 1=Output (read and write)
.label C2TALO = $DD04 // Read: actual value Timer A (Low Byte)
// Writing: Set latch of Timer A (Low Byte)
.label C2TAHI = $DD05 // Read: actual value Timer A (High Byte)
// Writing: Set latch of timer A (High Byte) - if the timer is stopped, the high-byte will automatically be re-set as well
.label C2TBLO = $DD06 // Read: actual value Timer B (Low Byte)
// Writing: Set latch of Timer B (Low Byte)
.label C2TBHI = $DD07 // Read: actual value Timer B (High Byte)
// Writing: Set latch of timer B (High Byte) - if the timer is stopped, the high-byte will automatically be re-set as well
.label C2TOD10THS = $DD08 // Read:
// Bit 0..3: Tenth seconds in BCD-format ($0-$9)
// Bit 4..7: always 0
// Writing:
// Bit 0..3: if CRB-Bit7=0: Set the tenth seconds in BCD-format
// Bit 0..3: if CRB-Bit7=1: Set the tenth seconds of the alarm time in BCD-format
.label C2TODSEC = $DD09 // Bit 0..3: Single seconds in BCD-format ($0-$9)
// Bit 4..6: Ten seconds in BCD-format ($0-$5)
// Bit 7: always 0
.label C2TODMIN = $DD0A // Bit 0..3: Single minutes in BCD-format( $0-$9)
// Bit 4..6: Ten minutes in BCD-format ($0-$5)
// Bit 7: always 0
.label C2TODHR = $DD0B // Bit 0..3: Single hours in BCD-format ($0-$9)
// Bit 4..6: Ten hours in BCD-format ($0-$5)
// Bit 7: Differentiation AM/PM, 0=AM, 1=PM
// Writing into this register stops TOD, until register 8 (TOD 10THS) will be read.
.label C2TSDR = $DD0C // The byte within this register will be shifted bitwise to or from the SP-pin with every positive slope at the CNT-pin.
.label C2ICR = $DD0D // CIA2 is connected to the NMI-Line.
// Bit 4: 1 = NMI Signal occured at FLAG-pin (RS-232 data received)
// Bit 7: 1 = NMI An interrupt occured, so at least one bit of INT MASK and INT DATA is set in both registers.
.label C2CRA = $DD0E // Control Timer A
// Bit 0: 0 = Stop timer; 1 = Start timer
// Bit 1: 1 = Indicates a timer underflow at port B in bit 6.
// Bit 2: 0 = Through a timer overflow, bit 6 of port B will get high for one cycle , 1 = Through a timer underflow, bit 6 of port B will be inverted
// Bit 3: 0 = Timer-restart after underflow (latch will be reloaded), 1 = Timer stops after underflow.
// Bit 4: 1 = Load latch into the timer once.
// Bit 5: 0 = Timer counts system cycles, 1 = Timer counts positive slope at CNT-pin
// Bit 6: Direction of the serial shift register, 0 = SP-pin is input (read), 1 = SP-pin is output (write)
// Bit 7: Real Time Clock, 0 = 60 Hz, 1 = 50 Hz
.label C2CRB = $DD0F // Control Timer B
// Bit 0: 0 = Stop timer; 1 = Start timer
// Bit 1: 1 = Indicates a timer underflow at port B in bit 7.
// Bit 2: 0 = Through a timer overflow, bit 7 of port B will get high for one cycle , 1 = Through a timer underflow, bit 7 of port B will be inverted
// Bit 3: 0 = Timer-restart after underflow (latch will be reloaded), 1 = Timer stops after underflow.
// Bit 4: 1 = Load latch into the timer once.
// Bit 5..6:
// %00 = Timer counts System cycle
// %01 = Timer counts positive slope on CNT-pin
// %10 = Timer counts underflow of timer A
// %11 = Timer counts underflow of timer A if the CNT-pin is high
// Bit 7: 0 = Writing into the TOD register sets the clock time, 1 = Writing into the TOD register sets the alarm time.
// ========================================================
// ////// METHODS /////////////////////////////////////////
// ========================================================
* = * "CIA HW"
init: {
lda #$7F // KILL INTERRUPTS
sta Cia.C1ICR
sta Cia.C2ICR
sta Cia.C1PRA // TURN ON STOP KEY
lda #%00001000 // SHUT OFF TIMERS
sta Cia.C1CRA
sta Cia.C2CRA
sta Cia.C1CRB
sta Cia.C2CRB
// CONFIGURE PORTS
ldx #$00 // SET UP KEYBOARD INPUTS
stx Cia.C1DDRB // KEYBOARD INPUTS
stx Cia.C2DDRB // USER PORT (NO RS-232)
stx Sid.FMVC // TURN OFF SID
dex // set X = $FF
stx Cia.C1DDRA // KEYBOARD OUTPUTS
lda #%00000111 // SET SERIAL/VA14/15 (CLKHI)
sta Cia.C2PRA
lda #%00111111 // ;SET SERIAL IN/OUT, VA14/15OUT
sta Cia.C2DDRA
rts
}