Files
aqhomecontrol/avr/modules/uart_hw/m_lowlevel_uart.asm
2025-02-09 21:06:31 +01:00

223 lines
6.0 KiB
NASM

; ***************************************************************************
; copyright : (C) 2025 by Martin Preuss
; email : martin@libchipcard.de
;
; ***************************************************************************
; * This file is part of the project "AqHome". *
; * Please see toplevel file COPYING of that project for license details. *
; ***************************************************************************
; ---------------------------------------------------------------------------
; @macro M_UART_HW_Uart_Init
;
; @param %0 UART number ("0" for UART0)
; @param Y pointer to interface data in SRAM (see @ref UART_HW_IFACE_OFFS_STATE)
; @clobbers R16, R17, X
.macro M_UART_HW_Uart_Init
rcall UART_HW_InterfaceInit
; set baudrate
.if clock == 8000000
ldi r16, 25 ; (19.2Kb/s at 8MHz)
ldi r17, 0
.endif
.if clock == 1000000
ldi r16, 2 ; (19.2Kb/s at 1MHz)
ldi r17, 0
.endif
sts UBRR@0H, r17
sts UBRR@0L, r16
; set character format
ldi r16, (1<<USBS@0)|(3<<UCSZ@00)
sts UCSR@0C, r16
.endmacro
; @end
; ---------------------------------------------------------------------------
; @macro M_UART_HW_Uart_StartRx
;
; @param %0 UART number ("0" for UART0)
; @clobbers none
.macro M_UART_HW_Uart_StartRx
lds r16, UCSR@0B
sbr r16, (1<<RXCIE@0) | (1<<RXEN@0) ; enable RX complete interrupt, enable receive
sts UCSR@0B, r16
.endmacro
; @end
; ---------------------------------------------------------------------------
; @macro M_UART_HW_Uart_StopRx
;
; @param %0 UART number ("0" for UART0)
; @clobbers R16
.macro M_UART_HW_Uart_StopRx
lds r16, UCSR@0B
cbr r16, (1<<RXCIE@0 | (1<<RXEN@0)) ; disable RX complete interrupt, disable receive
sts UCSR@0B, r16
.endmacro
; @end
; ---------------------------------------------------------------------------
; @macro M_UART_HW_Uart_StartTx
;
; @param %0 UART number ("0" for UART0)
; @param Y pointer to interface data in SRAM (see @ref UART_HW_IFACE_OFFS_STATE)
; @clobbers R16
.macro M_UART_HW_Uart_StartTx
lds r16, UCSR@0A
cbr r16, (1<<TXC@0) ; clear TXCn interrupt
sts UCSR@0A, r16
lds r16, UCSR@0B
sbr r16, (1<<UDRIE@0) | (1<<TXC@0) | (1<<TXEN@0) ; enable TX UDRE and TXC1 interrupt, enable transceive
sts UCSR@0B, r16
.endmacro
; @end
; ---------------------------------------------------------------------------
; @macro M_UART_HW_Uart_StopTx
;
; @param %0 UART number ("0" for UART0)
; @param Y pointer to interface data in SRAM (see @ref UART_HW_IFACE_OFFS_STATE)
; @clobbers R16
.macro M_UART_HW_Uart_StopTx
lds r16, UCSR@0B
cbr r16, (1<<UDRIE@0) | (1<<TXC@0) | (1<<TXEN@0) ; disable TX UDRE and TXC1 interrupt, enable transceive
sts UCSR@0B, r16
.endmacro
; @end
; ---------------------------------------------------------------------------
; @macro M_UART_HW_Uart_Flush
;
; Flush receiption buffer.
;
; @param %0 UART number ("0" for UART0)
; @param Y pointer to interface data in SRAM (see @ref UART_HW_IFACE_OFFS_MODE)
; @clobbers R16
.macro M_UART_HW_Uart_Flush
l_loop_%:
lds r16, UCSR@0A
sbrs r16, RXC@0
rjmp l_end_%
lds r16, UDR@0
clr r16
std Y+UART_HW_IFACE_OFFS_READTIMER, r16
rjmp l_loop_%
l_end_%:
.endmacro
; @end
; ---------------------------------------------------------------------------
; @macro M_UART_HW_Uart_RxCharIsr
;
; @param %0 UART number ("0" for UART0)
; @param Y pointer to interface data in SRAM (see @ref UART_HW_IFACE_OFFS_MODE)
; @clobbers R16 (R17, R18, X)
.macro M_UART_HW_Uart_RxCharIsr
lds r16, UCSR@0A ; check for errors
andi r16, (1<<FE@0) | (1<<DOR@0) | (1<<UPE@0)
breq l_recv_% ; no error, receive next char
ldd r16, Y+UART_HW_IFACE_OFFS_STATUS ; set error status
ori r16, (1<<UART_HW_STATUS_HWERR_BIT) ; -> HWERR
rjmp l_setStatusAndEnd_%
l_recv_%:
lds r16, UCSR@0A
sbrs r16, RXC@0
rjmp l_end_% ; no data
lds r16, UDR@0
rcall UART_HW_InterfaceWriteToReadBuffer ; (R17, R18, X)
brcc l_overrun_%
clr r16
std Y+UART_HW_IFACE_OFFS_READTIMER, r16 ; reset read timer
rjmp l_end_%
l_overrun_%:
ldd r16, Y+UART_HW_IFACE_OFFS_STATUS ; set overrun error
ori r16, (1<<UART_HW_STATUS_OVERRUN_BIT) ; -> OVERRUN
l_setStatusAndEnd_%:
std Y+UART_HW_IFACE_OFFS_STATUS, r16
l_end_%:
.endmacro
; @end
; ---------------------------------------------------------------------------
; @macro M_UART_HW_Uart_TxUdreIsr
;
; Handler for UDREn interrupt called when TX data register is empty.
;
; @param %0 UART number ("0" for UART0)
; @param Y pointer to interface data in SRAM (see @ref UART_HW_IFACE_OFFS_MODE)
; @clobbers R16, (R17, R18, X)
.macro M_UART_HW_Uart_TxUdreIsr
lds r16, UCSR@0A
sbrs r16,UDRE@0
rjmp l_end_% ; not ready
rcall UART_HW_InterfaceReadFromWriteBuffer ; (R17, R18, X)
brcs l_send_% ; got a byte, go send
; disable further DRE1 interrupts
lds r16, UCSR@0B
cbr r16, (1<<UDRIE@0) ; disable TX data register empty interrupt
sts UCSR@0B, r16
rjmp l_end_%
l_send_%:
sts UDR@0, r16
clr r16
std Y+UART_HW_IFACE_OFFS_WRITETIMER, r16 ; reset write timer
l_end_%:
.endmacro
; @end
; ---------------------------------------------------------------------------
; @macro M_UART_HW_Uart_TxCharIsr
;
; Handler for TXCn interrupt called when a last byte has been completely sent and
; the data register is empty..
;
; @param %0 UART number ("0" for UART0)
; @param Y pointer to interface data in SRAM (see @ref UART_HW_IFACE_OFFS_MODE)
; @clobbers R16, (R17, R18, X)
.macro M_UART_HW_Uart_TxCharIsr
; disable further TXC1 interrupts
lds r16, UCSR@0B
cbr r16, (1<<TXC@0) ; disable TXC1 interrupt
sts UCSR@0B, r16
; set underrun status (TODO: maybe change this later)
ldd r16, Y+UART_HW_IFACE_OFFS_STATUS ; set underrun error
ori r16, (1<<UART_HW_STATUS_UNDERRUN_BIT)
std Y+UART_HW_IFACE_OFFS_STATUS, r16
.endmacro
; @end