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Diffstat (limited to 'usbdrv/usbdrvasm20.inc')
| -rw-r--r-- | usbdrv/usbdrvasm20.inc | 360 |
1 files changed, 0 insertions, 360 deletions
diff --git a/usbdrv/usbdrvasm20.inc b/usbdrv/usbdrvasm20.inc deleted file mode 100644 index 303abaf64c..0000000000 --- a/usbdrv/usbdrvasm20.inc +++ /dev/null @@ -1,360 +0,0 @@ -/* Name: usbdrvasm20.inc - * Project: V-USB, virtual USB port for Atmel's(r) AVR(r) microcontrollers - * Author: Jeroen Benschop - * Based on usbdrvasm16.inc from Christian Starkjohann - * Creation Date: 2008-03-05 - * Tabsize: 4 - * Copyright: (c) 2008 by Jeroen Benschop and OBJECTIVE DEVELOPMENT Software GmbH - * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt) - * Revision: $Id: usbdrvasm20.inc 740 2009-04-13 18:23:31Z cs $ - */ - -/* Do not link this file! Link usbdrvasm.S instead, which includes the - * appropriate implementation! - */ - -/* -General Description: -This file is the 20 MHz version of the asssembler part of the USB driver. It -requires a 20 MHz crystal (not a ceramic resonator and not a calibrated RC -oscillator). - -See usbdrv.h for a description of the entire driver. - -Since almost all of this code is timing critical, don't change unless you -really know what you are doing! Many parts require not only a maximum number -of CPU cycles, but even an exact number of cycles! -*/ - -#define leap2 x3 -#ifdef __IAR_SYSTEMS_ASM__ -#define nextInst $+2 -#else -#define nextInst .+0 -#endif - -;max stack usage: [ret(2), YL, SREG, YH, bitcnt, shift, x1, x2, x3, x4, cnt] = 12 bytes -;nominal frequency: 20 MHz -> 13.333333 cycles per bit, 106.666667 cycles per byte -; Numbers in brackets are clocks counted from center of last sync bit -; when instruction starts -;register use in receive loop: -; shift assembles the byte currently being received -; x1 holds the D+ and D- line state -; x2 holds the previous line state -; x4 (leap) is used to add a leap cycle once every three bytes received -; X3 (leap2) is used to add a leap cycle once every three stuff bits received -; bitcnt is used to determine when a stuff bit is due -; cnt holds the number of bytes left in the receive buffer - -USB_INTR_VECTOR: -;order of registers pushed: YL, SREG YH, [sofError], bitcnt, shift, x1, x2, x3, x4, cnt - push YL ;[-28] push only what is necessary to sync with edge ASAP - in YL, SREG ;[-26] - push YL ;[-25] - push YH ;[-23] -;---------------------------------------------------------------------------- -; Synchronize with sync pattern: -;---------------------------------------------------------------------------- -;sync byte (D-) pattern LSb to MSb: 01010100 [1 = idle = J, 0 = K] -;sync up with J to K edge during sync pattern -- use fastest possible loops -;The first part waits at most 1 bit long since we must be in sync pattern. -;YL is guarenteed to be < 0x80 because I flag is clear. When we jump to -;waitForJ, ensure that this prerequisite is met. -waitForJ: - inc YL - sbis USBIN, USBMINUS - brne waitForJ ; just make sure we have ANY timeout -waitForK: -;The following code results in a sampling window of < 1/4 bit which meets the spec. - sbis USBIN, USBMINUS ;[-19] - rjmp foundK ;[-18] - sbis USBIN, USBMINUS - rjmp foundK - sbis USBIN, USBMINUS - rjmp foundK - sbis USBIN, USBMINUS - rjmp foundK - sbis USBIN, USBMINUS - rjmp foundK - sbis USBIN, USBMINUS - rjmp foundK - sbis USBIN, USBMINUS - rjmp foundK - sbis USBIN, USBMINUS - rjmp foundK - sbis USBIN, USBMINUS - rjmp foundK -#if USB_COUNT_SOF - lds YL, usbSofCount - inc YL - sts usbSofCount, YL -#endif /* USB_COUNT_SOF */ -#ifdef USB_SOF_HOOK - USB_SOF_HOOK -#endif - rjmp sofError -foundK: ;[-16] -;{3, 5} after falling D- edge, average delay: 4 cycles -;bit0 should be at 34 for center sampling. Currently at 4 so 30 cylces till bit 0 sample -;use 1 bit time for setup purposes, then sample again. Numbers in brackets -;are cycles from center of first sync (double K) bit after the instruction - push bitcnt ;[-16] -; [---] ;[-15] - lds YL, usbInputBufOffset;[-14] -; [---] ;[-13] - clr YH ;[-12] - subi YL, lo8(-(usbRxBuf));[-11] [rx loop init] - sbci YH, hi8(-(usbRxBuf));[-10] [rx loop init] - push shift ;[-9] -; [---] ;[-8] - ldi shift,0x40 ;[-7] set msb to "1" so processing bit7 can be detected - nop2 ;[-6] -; [---] ;[-5] - ldi bitcnt, 5 ;[-4] [rx loop init] - sbis USBIN, USBMINUS ;[-3] we want two bits K (sample 3 cycles too early) - rjmp haveTwoBitsK ;[-2] - pop shift ;[-1] undo the push from before - pop bitcnt ;[1] - rjmp waitForK ;[3] this was not the end of sync, retry -; The entire loop from waitForK until rjmp waitForK above must not exceed two -; bit times (= 27 cycles). - -;---------------------------------------------------------------------------- -; push more registers and initialize values while we sample the first bits: -;---------------------------------------------------------------------------- -haveTwoBitsK: - push x1 ;[0] - push x2 ;[2] - push x3 ;[4] (leap2) - ldi leap2, 0x55 ;[6] add leap cycle on 2nd,5th,8th,... stuff bit - push x4 ;[7] == leap - ldi leap, 0x55 ;[9] skip leap cycle on 2nd,5th,8th,... byte received - push cnt ;[10] - ldi cnt, USB_BUFSIZE ;[12] [rx loop init] - ldi x2, 1<<USBPLUS ;[13] current line state is K state. D+=="1", D-=="0" -bit0: - in x1, USBIN ;[0] sample line state - andi x1, USBMASK ;[1] filter only D+ and D- bits - rjmp handleBit ;[2] make bit0 14 cycles long - -;---------------------------------------------------------------------------- -; Process bit7. However, bit 6 still may need unstuffing. -;---------------------------------------------------------------------------- - -b6checkUnstuff: - dec bitcnt ;[9] - breq unstuff6 ;[10] -bit7: - subi cnt, 1 ;[11] cannot use dec becaus it does not affect the carry flag - brcs overflow ;[12] Too many bytes received. Ignore packet - in x1, USBIN ;[0] sample line state - andi x1, USBMASK ;[1] filter only D+ and D- bits - cpse x1, x2 ;[2] when previous line state equals current line state, handle "1" - rjmp b7handle0 ;[3] when line state differs, handle "0" - sec ;[4] - ror shift ;[5] shift "1" into the data - st y+, shift ;[6] store the data into the buffer - ldi shift, 0x40 ;[7] reset data for receiving the next byte - subi leap, 0x55 ;[9] trick to introduce a leap cycle every 3 bytes - brcc nextInst ;[10 or 11] it will fail after 85 bytes. However low speed can only receive 11 - dec bitcnt ;[11 or 12] - brne bit0 ;[12 or 13] - ldi x1, 1 ;[13 or 14] unstuffing bit 7 - in bitcnt, USBIN ;[0] sample stuff bit - rjmp unstuff ;[1] - -b7handle0: - mov x2,x1 ;[5] Set x2 to current line state - ldi bitcnt, 6 ;[6] - lsr shift ;[7] shift "0" into the data - st y+, shift ;[8] store data into the buffer - ldi shift, 0x40 ;[10] reset data for receiving the next byte - subi leap, 0x55 ;[11] trick to introduce a leap cycle every 3 bytes - brcs bit0 ;[12] it will fail after 85 bytes. However low speed can only receive 11 - rjmp bit0 ;[13] - - -;---------------------------------------------------------------------------- -; Handle unstuff -; x1==0xFF indicate unstuffing bit6 -;---------------------------------------------------------------------------- - -unstuff6: - ldi x1,0xFF ;[12] indicate unstuffing bit 6 - in bitcnt, USBIN ;[0] sample stuff bit - nop ;[1] fix timing -unstuff: ;b0-5 b6 b7 - mov x2,bitcnt ;[3] [2] [3] Set x2 to match line state - subi leap2, 0x55 ;[4] [3] [4] delay loop - brcs nextInst ;[5] [4] [5] add one cycle every three stuff bits - sbci leap2,0 ;[6] [5] [6] - ldi bitcnt,6 ;[7] [6] [7] reset bit stuff counter - andi x2, USBMASK ;[8] [7] [8] only keep D+ and D- - cpi x1,0 ;[9] [8] [9] - brmi bit7 ;[10] [9] [10] finished unstuffing bit6 When x1<0 - breq bitloop ;[11] --- [11] finished unstuffing bit0-5 when x1=0 - nop ;--- --- [12] - in x1, USBIN ;--- --- [0] sample line state for bit0 - andi x1, USBMASK ;--- --- [1] filter only D+ and D- bits - rjmp handleBit ;--- --- [2] make bit0 14 cycles long - -;---------------------------------------------------------------------------- -; Receiver loop (numbers in brackets are cycles within byte after instr) -;---------------------------------------------------------------------------- -bitloop: - in x1, USBIN ;[0] sample line state - andi x1, USBMASK ;[1] filter only D+ and D- bits - breq se0 ;[2] both lines are low so handle se0 -handleBit: - cpse x1, x2 ;[3] when previous line state equals current line state, handle "1" - rjmp handle0 ;[4] when line state differs, handle "0" - sec ;[5] - ror shift ;[6] shift "1" into the data - brcs b6checkUnstuff ;[7] When after shift C is set, next bit is bit7 - nop2 ;[8] - dec bitcnt ;[10] - brne bitloop ;[11] - ldi x1,0 ;[12] indicate unstuff for bit other than bit6 or bit7 - in bitcnt, USBIN ;[0] sample stuff bit - rjmp unstuff ;[1] - -handle0: - mov x2, x1 ;[6] Set x2 to current line state - ldi bitcnt, 6 ;[7] reset unstuff counter. - lsr shift ;[8] shift "0" into the data - brcs bit7 ;[9] When after shift C is set, next bit is bit7 - nop ;[10] - rjmp bitloop ;[11] - -;---------------------------------------------------------------------------- -; End of receive loop. Now start handling EOP -;---------------------------------------------------------------------------- - -macro POP_STANDARD ; 14 cycles - pop cnt - pop x4 - pop x3 - pop x2 - pop x1 - pop shift - pop bitcnt - endm -macro POP_RETI ; 7 cycles - pop YH - pop YL - out SREG, YL - pop YL - endm - - - -#include "asmcommon.inc" - -; USB spec says: -; idle = J -; J = (D+ = 0), (D- = 1) -; K = (D+ = 1), (D- = 0) -; Spec allows 7.5 bit times from EOP to SOP for replies -; 7.5 bit times is 100 cycles. This implementation arrives a bit later at se0 -; then specified in the include file but there is plenty of time - -bitstuffN: - eor x1, x4 ;[8] - ldi x2, 0 ;[9] - nop2 ;[10] - out USBOUT, x1 ;[12] <-- out - rjmp didStuffN ;[0] - -bitstuff7: - eor x1, x4 ;[6] - ldi x2, 0 ;[7] Carry is zero due to brcc - rol shift ;[8] compensate for ror shift at branch destination - nop2 ;[9] - rjmp didStuff7 ;[11] - -sendNakAndReti: - ldi x3, USBPID_NAK ;[-18] - rjmp sendX3AndReti ;[-17] -sendAckAndReti: - ldi cnt, USBPID_ACK ;[-17] -sendCntAndReti: - mov x3, cnt ;[-16] -sendX3AndReti: - ldi YL, 20 ;[-15] x3==r20 address is 20 - ldi YH, 0 ;[-14] - ldi cnt, 2 ;[-13] -; rjmp usbSendAndReti fallthrough - -;usbSend: -;pointer to data in 'Y' -;number of bytes in 'cnt' -- including sync byte [range 2 ... 12] -;uses: x1...x4, btcnt, shift, cnt, Y -;Numbers in brackets are time since first bit of sync pattern is sent -;We don't match the transfer rate exactly (don't insert leap cycles every third -;byte) because the spec demands only 1.5% precision anyway. -usbSendAndReti: ; 12 cycles until SOP - in x2, USBDDR ;[-12] - ori x2, USBMASK ;[-11] - sbi USBOUT, USBMINUS;[-10] prepare idle state; D+ and D- must have been 0 (no pullups) - in x1, USBOUT ;[-8] port mirror for tx loop - out USBDDR, x2 ;[-7] <- acquire bus -; need not init x2 (bitstuff history) because sync starts with 0 - ldi x4, USBMASK ;[-6] exor mask - ldi shift, 0x80 ;[-5] sync byte is first byte sent -txByteLoop: - ldi bitcnt, 0x49 ;[-4] [10] binary 01001001 -txBitLoop: - sbrs shift, 0 ;[-3] [10] [11] - eor x1, x4 ;[-2] [11] [12] - out USBOUT, x1 ;[-1] [12] [13] <-- out N - ror shift ;[0] [13] [14] - ror x2 ;[1] -didStuffN: - nop2 ;[2] - nop ;[4] - cpi x2, 0xfc ;[5] - brcc bitstuffN ;[6] - lsr bitcnt ;[7] - brcc txBitLoop ;[8] - brne txBitLoop ;[9] - - sbrs shift, 0 ;[10] - eor x1, x4 ;[11] -didStuff7: - out USBOUT, x1 ;[-1] [13] <-- out 7 - ror shift ;[0] [14] - ror x2 ;[1] - nop ;[2] - cpi x2, 0xfc ;[3] - brcc bitstuff7 ;[4] - ld shift, y+ ;[5] - dec cnt ;[7] - brne txByteLoop ;[8] -;make SE0: - cbr x1, USBMASK ;[9] prepare SE0 [spec says EOP may be 25 to 30 cycles] - lds x2, usbNewDeviceAddr;[10] - lsl x2 ;[12] we compare with left shifted address - out USBOUT, x1 ;[13] <-- out SE0 -- from now 2 bits = 22 cycles until bus idle - subi YL, 20 + 2 ;[0] Only assign address on data packets, not ACK/NAK in x3 - sbci YH, 0 ;[1] -;2006-03-06: moved transfer of new address to usbDeviceAddr from C-Code to asm: -;set address only after data packet was sent, not after handshake - breq skipAddrAssign ;[2] - sts usbDeviceAddr, x2; if not skipped: SE0 is one cycle longer -skipAddrAssign: -;end of usbDeviceAddress transfer - ldi x2, 1<<USB_INTR_PENDING_BIT;[4] int0 occurred during TX -- clear pending flag - USB_STORE_PENDING(x2) ;[5] - ori x1, USBIDLE ;[6] - in x2, USBDDR ;[7] - cbr x2, USBMASK ;[8] set both pins to input - mov x3, x1 ;[9] - cbr x3, USBMASK ;[10] configure no pullup on both pins - ldi x4, 5 ;[11] -se0Delay: - dec x4 ;[12] [15] [18] [21] [24] - brne se0Delay ;[13] [16] [19] [22] [25] - out USBOUT, x1 ;[26] <-- out J (idle) -- end of SE0 (EOP signal) - out USBDDR, x2 ;[27] <-- release bus now - out USBOUT, x3 ;[28] <-- ensure no pull-up resistors are active - rjmp doReturn |