SYS_WAIT
user defined wait cycle
HL: time in 1/10000s (10000 is 1 second)
SYS_BEEP
play tone using built-in speaker
A: tone index (pitch) C=3, D=4,...G=6, A=1, H(B)=2 (ASCII can be used too)
C:octave (0-...)
B: duration
LD A, 'C' ; "C"
LD B, 32 ; 32/128
LD C, 3 ; fourth octave
CALL BEEP ; beep
RST 20
send null-terminated string via serial line
no parameters
string must follow RST20 instruuction
RST 20
.TEXT "HELLO WORLD"
.DB 00h
SYS_KBD_INIT
send initialization sequence to keyboard
returns
B: error code
1- init OK
2- no response from keyboard
3- cannot change status indicator
4- error reading ID
5- cannont change scan code
6- cannot enable keyboard
SYS_KBD_LED
set/change LED indicator
A: LEDs status
bit 0 - Scroll Lock
bit 1 - Num Lock
bit 2 - Caps Lock
SYS_KBD_WRITE
write settings to keyboard
A: command or data to send
returns
CF: reset if ACK received from keyboard
SYS_KBD_READ
get keyboard data
returns
H: scan code from keyboard
L: MSB is parity flag
C: error code
00 - valid data
01 - communication error
FF - no key pressed
WAIT_FOR_KEY:
CALL SYS_KBD_READ
INC C
JR Z, WAIT_FOR_KEY
LD A, H
CP 0F0 ; key up?
SYS_KBD_BLOCK
keep keyboard transfer blocked, keys will be cached
no parameter
SYS_KBD_CHECK
check if keyboard is connected (sends echo command to keyboard)
returns
CF: reset if OK
SYS_TTY_WRITE
send one byte/char to serial line, no stop bit (needs some CPU time to create stop bit with desired length)
A: byte to send
SYS_TTY_READ
read one byte from serial line
return
L: byte from line
CF: set if error occurs
SYS_TTY_NEXT
read one byte, report timeout if no data
L: byte from line
CF: set if error or timout
; reading file example
TTY_GETFILE:
CALL SYS_TTY_READ ; wait for first byte
RET C ; report error (12T)
TTY_GETFILE1:
LD A, L ; byte to ACC ( 4T)
LD (DE), A ; store byte ( 7T)
INC DE ; move pointer ( 6T)
CALL SYS_TTY_NEXT ; read next byte or report timeout (17T)
JR NC, TTY_GETFILE1; save byte and read next one (12T)
XOR A ; flag: timeout
RET ; no more data on line
; return CF set if error
; return CF reset if timeout
SYS_I2C_START
i2c start condition
no parameters
SYS_I2C_STOP
i2c stop condition
no parameters
SYS_I2C_WRITE
send one byte to device
C: byte to write
CF: acknowledge from device
SYS_I2C_RD_ACK
read one byte from device, send positive acknowledge
return
C: byte from device
SYS_I2C_RD_NACK
read one byte from device, send negative acknowledge (often signalizing last byte)
return
C: byte from device
SYS_SPI_READ
read one byte from SPI device
return
C: byte from device
SYS_SPI_WRITE
write one byte to SPI device
C: byte to send
SYS_SPI_RDWR
read and write one byte
C: byte to send
return
C: byte from device
SYS_RTC_SETDATE
set actual date
D: day
E: month
H: year (last two digits)
L: day of week
values are BCD-coded
SYS_RTC_SETTIME
set time
D: hours
E: minutes
A: seconds
SYS_RTC_GETDATE
get date
return
D: day
E: month
H: year (last two digits)
L: day of week
SYS_RTC_GETTIME
get current time
return
D: hours
E: minutes
A: seconds