/* Name: sw-uart.S * Project: AVR USB driver for CDC interface on USB1.1 * Author: Osamu Tamura * Creation Date: 2006-05-12 * Tabsize: 4 * Copyright: (c) 2006 by Recursion Co., Ltd. * License: Proprietary, free under certain conditions. See Documentation. */ /* General Description: This module implements the assembler part of the USB-CDC driver. Note: This module violates the rule that interrupts must not be disabled for longer than a couple of instructions (see usbdrv.h). Running UART interrupt handlers with sei as the first instruction is not possible because it would recurse immediately (the cause of the interrupt has not been removed). If we collect the data and then call sei(), we win little. We therefore decide to violate the rule. The effect on USB operation is, that packages may be lost. This is equivalent to a package being dropped due to a CRC error. The host will therefore retry the transfer after a timeout. It is therefore very likely that no effect is seen at the application layer. */
#include "iarcompat.h" #ifndef __IAR_SYSTEMS_ASM__ /* configs for io.h */ # define __SFR_OFFSET 0 # define _VECTOR(N) __vector_ ## N /* io.h does not define this for asm */ # include /* for CPU I/O register definitions and vectors */ #endif /* __IAR_SYSTEMS_ASM__ */ #include "usbdrv.h" /* for common defs */ #include "uart.h"
#if !UART_CFG_HAVE_USART
/* register names */ #define x1 r16 #define x2 r17 /* Some assembler dependent definitions and declarations: */ #ifdef __IAR_SYSTEMS_ASM__ # define nop2 rjmp $+2 /* jump to next instruction */ # define XL r26 # define XH r27 # define YL r28 # define YH r29 # define ZL r30 # define ZH r31 # define lo8(x) LOW(x) # define hi8(x) ((x)>>8) /* not HIGH to allow XLINK to make a proper range check */ public bit_reverse
# ifndef IVT_BASE_ADDRESS # define IVT_BASE_ADDRESS 0 # endif ASEG ORG PCINT0_vect + IVT_BASE_ADDRESS rjmp SIG_PIN_CHANGE ORG TIM1_COMPA_vect + IVT_BASE_ADDRESS rjmp SIG_OUTPUT_COMPARE1A ORG USI_OVF_vect + IVT_BASE_ADDRESS rjmp SIG_USI_OVERFLOW RSEG CODE #else /* __IAR_SYSTEMS_ASM__ */ .text
.global SIG_PIN_CHANGE .type SIG_PIN_CHANGE, @function .global SIG_OUTPUT_COMPARE1A .type SIG_OUTPUT_COMPARE1A, @function .global SIG_USI_OVERFLOW .type SIG_USI_OVERFLOW, @function
.global bit_reverse
#endif /* __IAR_SYSTEMS_ASM__ */
; ######################## RS-232C functions ########################
SIG_PIN_CHANGE:
#if UART_CFG_INVERT
sbis UART_PIN, UART_CFG_RXD ;1/2
#else
sbic UART_PIN, UART_CFG_RXD ;1/2
#endif
reti ;4
out GPIOR0, x1 ;1
in x1, DT1A ;1 1st bit sampling delay
out TCNT1, x1 ;1
ldi x1, 9 ;1 set rx_bitcounter = 9
out OCR1C, x1 ;1
ldi x1, 7 ;1 start timer
out TCCR1, x1 ;1
ldi x1, (1 out USB_INTR_ENABLE, x1 ;1 stop pin change interrupt
in x1, GPIOR0 ;1
reti ;4 {14,14}
SIG_OUTPUT_COMPARE1A: out GPIOR0, x1 ;1
in x1, SREG ;1 out GPIOR1, x1 ;1
in x1, OCR1C ;1 rx_bitcounter--
dec x1 ;1
out OCR1C, x1 ;1
breq tm1_stopbit ;1/2
in x1, OCR1B ;1
lsr x1 ;1 data shift
#if UART_CFG_INVERT
sbis UART_PIN, UART_CFG_RXD ;1/2
#else
sbic UART_PIN, UART_CFG_RXD ;1/2
#endif
ori x1, 0x80 ;1
out OCR1B, x1 ;1
out GPIOR2, x2 ;1
in x1, TCNT1 ;1
in x2, OCR1A ;1
sub x1, x2 ;1
out TCNT1, x1 ;1
in x2, GPIOR2 ;1
in x1, GPIOR1 ;1
out SREG, x1 ;1 in x1, GPIOR0 ;1
reti ;4
tm1_stopbit:
out TCCR1, x1 ;1 stop timer1
out DT1B, x1 ;1 rx_data ready flag
in x1, OCR1B ;1
out EEDR, x1 ;1 rx_data
ldi x1, (1 out GIFR, x1 ;1
ldi x1, (1 out USB_INTR_ENABLE, x1 ;1 enable pin change interrupt
in x1, GPIOR1 ;1
out SREG, x1 ;1 in x1, GPIOR0 ;1
reti ;4 {23,25}
SIG_USI_OVERFLOW:
out GPIOR0, x1 ;1
sbic EEARL, 0 ;1/2
rjmp usi_stopbit ;2
ldi x1, 0x4b ;1
out USISR, x1 ;1
out EEARL, x1 ;1
in x1, OCR0B ;1
out USIDR, x1 ;1 transfer upper 4 bits
in x1, GPIOR0 ;1
reti ;4
usi_stopbit:
ldi x1, (1 out USISR, x1 ;1
ldi x1, 0 ;1
out TCCR0B, x1 ;1 stop timer0
in x1, GPIOR0 ;1
reti ;4 {13,13}
; extern uchar bit_reverse( uchar x );
#ifdef __IAR_SYSTEMS_ASM__ #define inb r16 #define outb r17 #else
#define inb r24 #define outb r25 #endif
bit_reverse:
rol inb
ror outb
rol inb
ror outb
rol inb
ror outb
rol inb
ror outb
rol inb
ror outb
rol inb
ror outb
rol inb
ror outb
rol inb
ror outb
mov inb, outb
ret
#endif /* UART_CFG_HAVE_USART */
