diff options
Diffstat (limited to 'vusb/usbdrv/usbdrvasm15.inc')
| -rw-r--r-- | vusb/usbdrv/usbdrvasm15.inc | 423 |
1 files changed, 423 insertions, 0 deletions
diff --git a/vusb/usbdrv/usbdrvasm15.inc b/vusb/usbdrv/usbdrvasm15.inc new file mode 100644 index 0000000000..401b7f8fff --- /dev/null +++ b/vusb/usbdrv/usbdrvasm15.inc @@ -0,0 +1,423 @@ +/* Name: usbdrvasm15.inc + * Project: V-USB, virtual USB port for Atmel's(r) AVR(r) microcontrollers + * Author: contributed by V. Bosch + * Creation Date: 2007-08-06 + * Tabsize: 4 + * Copyright: (c) 2007 by OBJECTIVE DEVELOPMENT Software GmbH + * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt) + * Revision: $Id: usbdrvasm15.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 15 MHz version of the asssembler part of the USB driver. It +requires a 15 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! +*/ + +;max stack usage: [ret(2), YL, SREG, YH, bitcnt, shift, x1, x2, x3, x4, cnt] = 12 bytes +;nominal frequency: 15 MHz -> 10.0 cycles per bit, 80.0 cycles per byte +; Numbers in brackets are clocks counted from center of last sync bit +; when instruction starts + +;---------------------------------------------------------------------------- +; order of registers pushed: +; YL, SREG [sofError] YH, shift, x1, x2, x3, bitcnt, cnt, x4 +;---------------------------------------------------------------------------- +USB_INTR_VECTOR: + push YL ;2 push only what is necessary to sync with edge ASAP + in YL, SREG ;1 + push YL ;2 +;---------------------------------------------------------------------------- +; 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 +;------------------------------------------------------------------------------- +; The following code results in a sampling window of < 1/4 bit +; which meets the spec. +;------------------------------------------------------------------------------- +waitForK: ;- + sbis USBIN, USBMINUS ;1 [00] <-- sample + rjmp foundK ;2 [01] + sbis USBIN, USBMINUS ; <-- sample + rjmp foundK + sbis USBIN, USBMINUS ; <-- sample + rjmp foundK + sbis USBIN, USBMINUS ; <-- sample + rjmp foundK + sbis USBIN, USBMINUS ; <-- sample + rjmp foundK + sbis USBIN, USBMINUS ; <-- sample + 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 +;------------------------------------------------------------------------------ +; {3, 5} after falling D- edge, average delay: 4 cycles [we want 5 for +; center sampling] +; we have 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 +;------------------------------------------------------------------------------ +foundK: ;- [02] + lds YL, usbInputBufOffset;2 [03+04] tx loop + push YH ;2 [05+06] + clr YH ;1 [07] + subi YL, lo8(-(usbRxBuf)) ;1 [08] [rx loop init] + sbci YH, hi8(-(usbRxBuf)) ;1 [09] [rx loop init] + push shift ;2 [10+11] + ser shift ;1 [12] + sbis USBIN, USBMINUS ;1 [-1] [13] <--sample:we want two bits K (sample 1 cycle too early) + rjmp haveTwoBitsK ;2 [00] [14] + pop shift ;2 [15+16] undo the push from before + pop YH ;2 [17+18] undo the push from before + rjmp waitForK ;2 [19+20] this was not the end of sync, retry +; The entire loop from waitForK until rjmp waitForK above must not exceed two +; bit times (= 20 cycles). + +;---------------------------------------------------------------------------- +; push more registers and initialize values while we sample the first bits: +;---------------------------------------------------------------------------- +haveTwoBitsK: ;- [01] + push x1 ;2 [02+03] + push x2 ;2 [04+05] + push x3 ;2 [06+07] + push bitcnt ;2 [08+09] + in x1, USBIN ;1 [00] [10] <-- sample bit 0 + bst x1, USBMINUS ;1 [01] + bld shift, 0 ;1 [02] + push cnt ;2 [03+04] + ldi cnt, USB_BUFSIZE ;1 [05] + push x4 ;2 [06+07] tx loop + rjmp rxLoop ;2 [08] +;---------------------------------------------------------------------------- +; Receiver loop (numbers in brackets are cycles within byte after instr) +;---------------------------------------------------------------------------- +unstuff0: ;- [07] (branch taken) + andi x3, ~0x01 ;1 [08] + mov x1, x2 ;1 [09] x2 contains last sampled (stuffed) bit + in x2, USBIN ;1 [00] [10] <-- sample bit 1 again + andi x2, USBMASK ;1 [01] + breq se0Hop ;1 [02] SE0 check for bit 1 + ori shift, 0x01 ;1 [03] 0b00000001 + nop ;1 [04] + rjmp didUnstuff0 ;2 [05] +;----------------------------------------------------- +unstuff1: ;- [05] (branch taken) + mov x2, x1 ;1 [06] x1 contains last sampled (stuffed) bit + andi x3, ~0x02 ;1 [07] + ori shift, 0x02 ;1 [08] 0b00000010 + nop ;1 [09] + in x1, USBIN ;1 [00] [10] <-- sample bit 2 again + andi x1, USBMASK ;1 [01] + breq se0Hop ;1 [02] SE0 check for bit 2 + rjmp didUnstuff1 ;2 [03] +;----------------------------------------------------- +unstuff2: ;- [05] (branch taken) + andi x3, ~0x04 ;1 [06] + ori shift, 0x04 ;1 [07] 0b00000100 + mov x1, x2 ;1 [08] x2 contains last sampled (stuffed) bit + nop ;1 [09] + in x2, USBIN ;1 [00] [10] <-- sample bit 3 + andi x2, USBMASK ;1 [01] + breq se0Hop ;1 [02] SE0 check for bit 3 + rjmp didUnstuff2 ;2 [03] +;----------------------------------------------------- +unstuff3: ;- [00] [10] (branch taken) + in x2, USBIN ;1 [01] [11] <-- sample stuffed bit 3 one cycle too late + andi x2, USBMASK ;1 [02] + breq se0Hop ;1 [03] SE0 check for stuffed bit 3 + andi x3, ~0x08 ;1 [04] + ori shift, 0x08 ;1 [05] 0b00001000 + rjmp didUnstuff3 ;2 [06] +;---------------------------------------------------------------------------- +; extra jobs done during bit interval: +; +; bit 0: store, clear [SE0 is unreliable here due to bit dribbling in hubs], +; overflow check, jump to the head of rxLoop +; bit 1: SE0 check +; bit 2: SE0 check, recovery from delay [bit 0 tasks took too long] +; bit 3: SE0 check, recovery from delay [bit 0 tasks took too long] +; bit 4: SE0 check, none +; bit 5: SE0 check, none +; bit 6: SE0 check, none +; bit 7: SE0 check, reconstruct: x3 is 0 at bit locations we changed, 1 at others +;---------------------------------------------------------------------------- +rxLoop: ;- [09] + in x2, USBIN ;1 [00] [10] <-- sample bit 1 (or possibly bit 0 stuffed) + andi x2, USBMASK ;1 [01] + brne SkipSe0Hop ;1 [02] +se0Hop: ;- [02] + rjmp se0 ;2 [03] SE0 check for bit 1 +SkipSe0Hop: ;- [03] + ser x3 ;1 [04] + andi shift, 0xf9 ;1 [05] 0b11111001 + breq unstuff0 ;1 [06] +didUnstuff0: ;- [06] + eor x1, x2 ;1 [07] + bst x1, USBMINUS ;1 [08] + bld shift, 1 ;1 [09] + in x1, USBIN ;1 [00] [10] <-- sample bit 2 (or possibly bit 1 stuffed) + andi x1, USBMASK ;1 [01] + breq se0Hop ;1 [02] SE0 check for bit 2 + andi shift, 0xf3 ;1 [03] 0b11110011 + breq unstuff1 ;1 [04] do remaining work for bit 1 +didUnstuff1: ;- [04] + eor x2, x1 ;1 [05] + bst x2, USBMINUS ;1 [06] + bld shift, 2 ;1 [07] + nop2 ;2 [08+09] + in x2, USBIN ;1 [00] [10] <-- sample bit 3 (or possibly bit 2 stuffed) + andi x2, USBMASK ;1 [01] + breq se0Hop ;1 [02] SE0 check for bit 3 + andi shift, 0xe7 ;1 [03] 0b11100111 + breq unstuff2 ;1 [04] +didUnstuff2: ;- [04] + eor x1, x2 ;1 [05] + bst x1, USBMINUS ;1 [06] + bld shift, 3 ;1 [07] +didUnstuff3: ;- [07] + andi shift, 0xcf ;1 [08] 0b11001111 + breq unstuff3 ;1 [09] + in x1, USBIN ;1 [00] [10] <-- sample bit 4 + andi x1, USBMASK ;1 [01] + breq se0Hop ;1 [02] SE0 check for bit 4 + eor x2, x1 ;1 [03] + bst x2, USBMINUS ;1 [04] + bld shift, 4 ;1 [05] +didUnstuff4: ;- [05] + andi shift, 0x9f ;1 [06] 0b10011111 + breq unstuff4 ;1 [07] + nop2 ;2 [08+09] + in x2, USBIN ;1 [00] [10] <-- sample bit 5 + andi x2, USBMASK ;1 [01] + breq se0 ;1 [02] SE0 check for bit 5 + eor x1, x2 ;1 [03] + bst x1, USBMINUS ;1 [04] + bld shift, 5 ;1 [05] +didUnstuff5: ;- [05] + andi shift, 0x3f ;1 [06] 0b00111111 + breq unstuff5 ;1 [07] + nop2 ;2 [08+09] + in x1, USBIN ;1 [00] [10] <-- sample bit 6 + andi x1, USBMASK ;1 [01] + breq se0 ;1 [02] SE0 check for bit 6 + eor x2, x1 ;1 [03] + bst x2, USBMINUS ;1 [04] + bld shift, 6 ;1 [05] +didUnstuff6: ;- [05] + cpi shift, 0x02 ;1 [06] 0b00000010 + brlo unstuff6 ;1 [07] + nop2 ;2 [08+09] + in x2, USBIN ;1 [00] [10] <-- sample bit 7 + andi x2, USBMASK ;1 [01] + breq se0 ;1 [02] SE0 check for bit 7 + eor x1, x2 ;1 [03] + bst x1, USBMINUS ;1 [04] + bld shift, 7 ;1 [05] +didUnstuff7: ;- [05] + cpi shift, 0x04 ;1 [06] 0b00000100 + brlo unstuff7 ;1 [07] + eor x3, shift ;1 [08] reconstruct: x3 is 0 at bit locations we changed, 1 at others + nop ;1 [09] + in x1, USBIN ;1 [00] [10] <-- sample bit 0 + st y+, x3 ;2 [01+02] store data + eor x2, x1 ;1 [03] + bst x2, USBMINUS ;1 [04] + bld shift, 0 ;1 [05] + subi cnt, 1 ;1 [06] + brcs overflow ;1 [07] + rjmp rxLoop ;2 [08] +;----------------------------------------------------- +unstuff4: ;- [08] + andi x3, ~0x10 ;1 [09] + in x1, USBIN ;1 [00] [10] <-- sample stuffed bit 4 + andi x1, USBMASK ;1 [01] + breq se0 ;1 [02] SE0 check for stuffed bit 4 + ori shift, 0x10 ;1 [03] + rjmp didUnstuff4 ;2 [04] +;----------------------------------------------------- +unstuff5: ;- [08] + ori shift, 0x20 ;1 [09] + in x2, USBIN ;1 [00] [10] <-- sample stuffed bit 5 + andi x2, USBMASK ;1 [01] + breq se0 ;1 [02] SE0 check for stuffed bit 5 + andi x3, ~0x20 ;1 [03] + rjmp didUnstuff5 ;2 [04] +;----------------------------------------------------- +unstuff6: ;- [08] + andi x3, ~0x40 ;1 [09] + in x1, USBIN ;1 [00] [10] <-- sample stuffed bit 6 + andi x1, USBMASK ;1 [01] + breq se0 ;1 [02] SE0 check for stuffed bit 6 + ori shift, 0x40 ;1 [03] + rjmp didUnstuff6 ;2 [04] +;----------------------------------------------------- +unstuff7: ;- [08] + andi x3, ~0x80 ;1 [09] + in x2, USBIN ;1 [00] [10] <-- sample stuffed bit 7 + andi x2, USBMASK ;1 [01] + breq se0 ;1 [02] SE0 check for stuffed bit 7 + ori shift, 0x80 ;1 [03] + rjmp didUnstuff7 ;2 [04] + +macro POP_STANDARD ; 16 cycles + pop x4 + pop cnt + pop bitcnt + pop x3 + pop x2 + pop x1 + pop shift + pop YH + endm +macro POP_RETI ; 5 cycles + 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 +;--------------------------------------------------------------------------- +bitstuffN: ;- [04] + eor x1, x4 ;1 [05] + clr x2 ;1 [06] + nop ;1 [07] + rjmp didStuffN ;1 [08] +;--------------------------------------------------------------------------- +bitstuff6: ;- [04] + eor x1, x4 ;1 [05] + clr x2 ;1 [06] + rjmp didStuff6 ;1 [07] +;--------------------------------------------------------------------------- +bitstuff7: ;- [02] + eor x1, x4 ;1 [03] + clr x2 ;1 [06] + nop ;1 [05] + rjmp didStuff7 ;1 [06] +;--------------------------------------------------------------------------- +sendNakAndReti: ;- [-19] + ldi x3, USBPID_NAK ;1 [-18] + rjmp sendX3AndReti ;1 [-17] +;--------------------------------------------------------------------------- +sendAckAndReti: ;- [-17] + ldi cnt, USBPID_ACK ;1 [-16] +sendCntAndReti: ;- [-16] + mov x3, cnt ;1 [-15] +sendX3AndReti: ;- [-15] + ldi YL, 20 ;1 [-14] x3==r20 address is 20 + ldi YH, 0 ;1 [-13] + ldi cnt, 2 ;1 [-12] +; 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 need not to match the transfer rate exactly because the spec demands +;only 1.5% precision anyway. +usbSendAndReti: ;- [-13] 13 cycles until SOP + in x2, USBDDR ;1 [-12] + ori x2, USBMASK ;1 [-11] + sbi USBOUT, USBMINUS ;2 [-09-10] prepare idle state; D+ and D- must have been 0 (no pullups) + in x1, USBOUT ;1 [-08] port mirror for tx loop + out USBDDR, x2 ;1 [-07] <- acquire bus + ; need not init x2 (bitstuff history) because sync starts with 0 + ldi x4, USBMASK ;1 [-06] exor mask + ldi shift, 0x80 ;1 [-05] sync byte is first byte sent + ldi bitcnt, 6 ;1 [-04] +txBitLoop: ;- [-04] [06] + sbrs shift, 0 ;1 [-03] [07] + eor x1, x4 ;1 [-02] [08] + ror shift ;1 [-01] [09] +didStuffN: ;- [09] + out USBOUT, x1 ;1 [00] [10] <-- out N + ror x2 ;1 [01] + cpi x2, 0xfc ;1 [02] + brcc bitstuffN ;1 [03] + dec bitcnt ;1 [04] + brne txBitLoop ;1 [05] + sbrs shift, 0 ;1 [06] + eor x1, x4 ;1 [07] + ror shift ;1 [08] +didStuff6: ;- [08] + nop ;1 [09] + out USBOUT, x1 ;1 [00] [10] <-- out 6 + ror x2 ;1 [01] + cpi x2, 0xfc ;1 [02] + brcc bitstuff6 ;1 [03] + sbrs shift, 0 ;1 [04] + eor x1, x4 ;1 [05] + ror shift ;1 [06] + ror x2 ;1 [07] +didStuff7: ;- [07] + ldi bitcnt, 6 ;1 [08] + cpi x2, 0xfc ;1 [09] + out USBOUT, x1 ;1 [00] [10] <-- out 7 + brcc bitstuff7 ;1 [01] + ld shift, y+ ;2 [02+03] + dec cnt ;1 [04] + brne txBitLoop ;1 [05] +makeSE0: + cbr x1, USBMASK ;1 [06] prepare SE0 [spec says EOP may be 19 to 23 cycles] + lds x2, usbNewDeviceAddr;2 [07+08] + lsl x2 ;1 [09] we compare with left shifted address +;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 + out USBOUT, x1 ;1 [00] [10] <-- out SE0-- from now 2 bits==20 cycl. until bus idle + subi YL, 20 + 2 ;1 [01] Only assign address on data packets, not ACK/NAK in x3 + sbci YH, 0 ;1 [02] + breq skipAddrAssign ;1 [03] + sts usbDeviceAddr, x2 ;2 [04+05] if not skipped: SE0 is one cycle longer +;---------------------------------------------------------------------------- +;end of usbDeviceAddress transfer +skipAddrAssign: ;- [03/04] + ldi x2, 1<<USB_INTR_PENDING_BIT ;1 [05] int0 occurred during TX -- clear pending flag + USB_STORE_PENDING(x2) ;1 [06] + ori x1, USBIDLE ;1 [07] + in x2, USBDDR ;1 [08] + cbr x2, USBMASK ;1 [09] set both pins to input + mov x3, x1 ;1 [10] + cbr x3, USBMASK ;1 [11] configure no pullup on both pins + ldi x4, 3 ;1 [12] +se0Delay: ;- [12] [15] + dec x4 ;1 [13] [16] + brne se0Delay ;1 [14] [17] + nop2 ;2 [18+19] + out USBOUT, x1 ;1 [20] <--out J (idle) -- end of SE0 (EOP sig.) + out USBDDR, x2 ;1 [21] <--release bus now + out USBOUT, x3 ;1 [22] <--ensure no pull-up resistors are active + rjmp doReturn ;1 [23] +;--------------------------------------------------------------------------- |