diff options
Diffstat (limited to 'protocol/vusb/usbdrv/usbdrvasm165.inc')
| -rw-r--r-- | protocol/vusb/usbdrv/usbdrvasm165.inc | 453 |
1 files changed, 453 insertions, 0 deletions
diff --git a/protocol/vusb/usbdrv/usbdrvasm165.inc b/protocol/vusb/usbdrv/usbdrvasm165.inc new file mode 100644 index 0000000000..79b3c61cf8 --- /dev/null +++ b/protocol/vusb/usbdrv/usbdrvasm165.inc @@ -0,0 +1,453 @@ +/* Name: usbdrvasm165.inc + * Project: V-USB, virtual USB port for Atmel's(r) AVR(r) microcontrollers + * Author: Christian Starkjohann + * Creation Date: 2007-04-22 + * 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: usbdrvasm165.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 16.5 MHz version of the USB driver. It is intended for the +ATTiny45 and similar controllers running on 16.5 MHz internal RC oscillator. +This version contains a phase locked loop in the receiver routine to cope with +slight clock rate deviations of up to +/- 1%. + +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! +*/ + +;Software-receiver engine. Strict timing! Don't change unless you can preserve timing! +;interrupt response time: 4 cycles + insn running = 7 max if interrupts always enabled +;max allowable interrupt latency: 59 cycles -> max 52 cycles interrupt disable +;max stack usage: [ret(2), r0, SREG, YL, YH, shift, x1, x2, x3, x4, cnt] = 12 bytes +;nominal frequency: 16.5 MHz -> 11 cycles per bit +; 16.3125 MHz < F_CPU < 16.6875 MHz (+/- 1.1%) +; Numbers in brackets are clocks counted from center of last sync bit +; when instruction starts + + +USB_INTR_VECTOR: +;order of registers pushed: YL, SREG [sofError], r0, YH, shift, x1, x2, x3, x4, cnt + push YL ;[-23] push only what is necessary to sync with edge ASAP + in YL, SREG ;[-21] + push YL ;[-20] +;---------------------------------------------------------------------------- +; 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 ;[-15] + rjmp foundK ;[-14] + 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: ;[-12] +;{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 + push r0 ;[-12] +; [---] ;[-11] + push YH ;[-10] +; [---] ;[-9] + lds YL, usbInputBufOffset;[-8] +; [---] ;[-7] + clr YH ;[-6] + subi YL, lo8(-(usbRxBuf));[-5] [rx loop init] + sbci YH, hi8(-(usbRxBuf));[-4] [rx loop init] + mov r0, x2 ;[-3] [rx loop init] + sbis USBIN, USBMINUS ;[-2] we want two bits K (sample 2 cycles too early) + rjmp haveTwoBitsK ;[-1] + pop YH ;[0] undo the pushes from before + pop r0 ;[2] + rjmp waitForK ;[4] this was not the end of sync, retry +; The entire loop from waitForK until rjmp waitForK above must not exceed two +; bit times (= 22 cycles). + +;---------------------------------------------------------------------------- +; push more registers and initialize values while we sample the first bits: +;---------------------------------------------------------------------------- +haveTwoBitsK: ;[1] + push shift ;[1] + push x1 ;[3] + push x2 ;[5] + push x3 ;[7] + ldi shift, 0xff ;[9] [rx loop init] + ori x3, 0xff ;[10] [rx loop init] == ser x3, clear zero flag + + in x1, USBIN ;[11] <-- sample bit 0 + bst x1, USBMINUS ;[12] + bld shift, 0 ;[13] + push x4 ;[14] == phase +; [---] ;[15] + push cnt ;[16] +; [---] ;[17] + ldi phase, 0 ;[18] [rx loop init] + ldi cnt, USB_BUFSIZE;[19] [rx loop init] + rjmp rxbit1 ;[20] +; [---] ;[21] + +;---------------------------------------------------------------------------- +; Receiver loop (numbers in brackets are cycles within byte after instr) +;---------------------------------------------------------------------------- +/* +byte oriented operations done during loop: +bit 0: store data +bit 1: SE0 check +bit 2: overflow check +bit 3: catch up +bit 4: rjmp to achieve conditional jump range +bit 5: PLL +bit 6: catch up +bit 7: jump, fixup bitstuff +; 87 [+ 2] cycles +------------------------------------------------------------------ +*/ +continueWithBit5: + in x2, USBIN ;[055] <-- bit 5 + eor r0, x2 ;[056] + or phase, r0 ;[057] + sbrc phase, USBMINUS ;[058] + lpm ;[059] optional nop3; modifies r0 + in phase, USBIN ;[060] <-- phase + eor x1, x2 ;[061] + bst x1, USBMINUS ;[062] + bld shift, 5 ;[063] + andi shift, 0x3f ;[064] + in x1, USBIN ;[065] <-- bit 6 + breq unstuff5 ;[066] *** unstuff escape + eor phase, x1 ;[067] + eor x2, x1 ;[068] + bst x2, USBMINUS ;[069] + bld shift, 6 ;[070] +didUnstuff6: ;[ ] + in r0, USBIN ;[071] <-- phase + cpi shift, 0x02 ;[072] + brlo unstuff6 ;[073] *** unstuff escape +didUnstuff5: ;[ ] + nop2 ;[074] +; [---] ;[075] + in x2, USBIN ;[076] <-- bit 7 + eor x1, x2 ;[077] + bst x1, USBMINUS ;[078] + bld shift, 7 ;[079] +didUnstuff7: ;[ ] + eor r0, x2 ;[080] + or phase, r0 ;[081] + in r0, USBIN ;[082] <-- phase + cpi shift, 0x04 ;[083] + brsh rxLoop ;[084] +; [---] ;[085] +unstuff7: ;[ ] + andi x3, ~0x80 ;[085] + ori shift, 0x80 ;[086] + in x2, USBIN ;[087] <-- sample stuffed bit 7 + nop ;[088] + rjmp didUnstuff7 ;[089] +; [---] ;[090] + ;[080] + +unstuff5: ;[067] + eor phase, x1 ;[068] + andi x3, ~0x20 ;[069] + ori shift, 0x20 ;[070] + in r0, USBIN ;[071] <-- phase + mov x2, x1 ;[072] + nop ;[073] + nop2 ;[074] +; [---] ;[075] + in x1, USBIN ;[076] <-- bit 6 + eor r0, x1 ;[077] + or phase, r0 ;[078] + eor x2, x1 ;[079] + bst x2, USBMINUS ;[080] + bld shift, 6 ;[081] no need to check bitstuffing, we just had one + in r0, USBIN ;[082] <-- phase + rjmp didUnstuff5 ;[083] +; [---] ;[084] + ;[074] + +unstuff6: ;[074] + andi x3, ~0x40 ;[075] + in x1, USBIN ;[076] <-- bit 6 again + ori shift, 0x40 ;[077] + nop2 ;[078] +; [---] ;[079] + rjmp didUnstuff6 ;[080] +; [---] ;[081] + ;[071] + +unstuff0: ;[013] + eor r0, x2 ;[014] + or phase, r0 ;[015] + andi x2, USBMASK ;[016] check for SE0 + in r0, USBIN ;[017] <-- phase + breq didUnstuff0 ;[018] direct jump to se0 would be too long + andi x3, ~0x01 ;[019] + ori shift, 0x01 ;[020] + mov x1, x2 ;[021] mov existing sample + in x2, USBIN ;[022] <-- bit 1 again + rjmp didUnstuff0 ;[023] +; [---] ;[024] + ;[014] + +unstuff1: ;[024] + eor r0, x1 ;[025] + or phase, r0 ;[026] + andi x3, ~0x02 ;[027] + in r0, USBIN ;[028] <-- phase + ori shift, 0x02 ;[029] + mov x2, x1 ;[030] + rjmp didUnstuff1 ;[031] +; [---] ;[032] + ;[022] + +unstuff2: ;[035] + eor r0, x2 ;[036] + or phase, r0 ;[037] + andi x3, ~0x04 ;[038] + in r0, USBIN ;[039] <-- phase + ori shift, 0x04 ;[040] + mov x1, x2 ;[041] + rjmp didUnstuff2 ;[042] +; [---] ;[043] + ;[033] + +unstuff3: ;[043] + in x2, USBIN ;[044] <-- bit 3 again + eor r0, x2 ;[045] + or phase, r0 ;[046] + andi x3, ~0x08 ;[047] + ori shift, 0x08 ;[048] + nop ;[049] + in r0, USBIN ;[050] <-- phase + rjmp didUnstuff3 ;[051] +; [---] ;[052] + ;[042] + +unstuff4: ;[053] + andi x3, ~0x10 ;[054] + in x1, USBIN ;[055] <-- bit 4 again + ori shift, 0x10 ;[056] + rjmp didUnstuff4 ;[057] +; [---] ;[058] + ;[048] + +rxLoop: ;[085] + eor x3, shift ;[086] reconstruct: x3 is 0 at bit locations we changed, 1 at others + in x1, USBIN ;[000] <-- bit 0 + st y+, x3 ;[001] +; [---] ;[002] + eor r0, x1 ;[003] + or phase, r0 ;[004] + eor x2, x1 ;[005] + in r0, USBIN ;[006] <-- phase + ser x3 ;[007] + bst x2, USBMINUS ;[008] + bld shift, 0 ;[009] + andi shift, 0xf9 ;[010] +rxbit1: ;[ ] + in x2, USBIN ;[011] <-- bit 1 + breq unstuff0 ;[012] *** unstuff escape + andi x2, USBMASK ;[013] SE0 check for bit 1 +didUnstuff0: ;[ ] Z only set if we detected SE0 in bitstuff + breq se0 ;[014] + eor r0, x2 ;[015] + or phase, r0 ;[016] + in r0, USBIN ;[017] <-- phase + eor x1, x2 ;[018] + bst x1, USBMINUS ;[019] + bld shift, 1 ;[020] + andi shift, 0xf3 ;[021] +didUnstuff1: ;[ ] + in x1, USBIN ;[022] <-- bit 2 + breq unstuff1 ;[023] *** unstuff escape + eor r0, x1 ;[024] + or phase, r0 ;[025] + subi cnt, 1 ;[026] overflow check + brcs overflow ;[027] + in r0, USBIN ;[028] <-- phase + eor x2, x1 ;[029] + bst x2, USBMINUS ;[030] + bld shift, 2 ;[031] + andi shift, 0xe7 ;[032] +didUnstuff2: ;[ ] + in x2, USBIN ;[033] <-- bit 3 + breq unstuff2 ;[034] *** unstuff escape + eor r0, x2 ;[035] + or phase, r0 ;[036] + eor x1, x2 ;[037] + bst x1, USBMINUS ;[038] + in r0, USBIN ;[039] <-- phase + bld shift, 3 ;[040] + andi shift, 0xcf ;[041] +didUnstuff3: ;[ ] + breq unstuff3 ;[042] *** unstuff escape + nop ;[043] + in x1, USBIN ;[044] <-- bit 4 + eor x2, x1 ;[045] + bst x2, USBMINUS ;[046] + bld shift, 4 ;[047] +didUnstuff4: ;[ ] + eor r0, x1 ;[048] + or phase, r0 ;[049] + in r0, USBIN ;[050] <-- phase + andi shift, 0x9f ;[051] + breq unstuff4 ;[052] *** unstuff escape + rjmp continueWithBit5;[053] +; [---] ;[054] + +macro POP_STANDARD ; 16 cycles + pop cnt + pop x4 + pop x3 + pop x2 + pop x1 + pop shift + pop YH + pop r0 + 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 + +bitstuff7: + eor x1, x4 ;[4] + ldi x2, 0 ;[5] + nop2 ;[6] C is zero (brcc) + rjmp didStuff7 ;[8] + +bitstuffN: + eor x1, x4 ;[5] + ldi x2, 0 ;[6] + lpm ;[7] 3 cycle NOP, modifies r0 + out USBOUT, x1 ;[10] <-- out + rjmp didStuffN ;[0] + +#define bitStatus x3 + +sendNakAndReti: + ldi cnt, USBPID_NAK ;[-19] + rjmp sendCntAndReti ;[-18] +sendAckAndReti: + ldi cnt, USBPID_ACK ;[-17] +sendCntAndReti: + mov r0, cnt ;[-16] + ldi YL, 0 ;[-15] R0 address is 0 + 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, shift, cnt, Y +;Numbers in brackets are time since first bit of sync pattern is sent +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 + ldi bitStatus, 0xff ;[-4] init bit loop counter, works for up to 12 bytes +byteloop: +bitloop: + sbrs shift, 0 ;[8] [-3] + eor x1, x4 ;[9] [-2] + out USBOUT, x1 ;[10] [-1] <-- out + ror shift ;[0] + ror x2 ;[1] +didStuffN: + cpi x2, 0xfc ;[2] + brcc bitstuffN ;[3] + nop ;[4] + subi bitStatus, 37 ;[5] 256 / 7 ~=~ 37 + brcc bitloop ;[6] when we leave the loop, bitStatus has almost the initial value + sbrs shift, 0 ;[7] + eor x1, x4 ;[8] + ror shift ;[9] +didStuff7: + out USBOUT, x1 ;[10] <-- out + ror x2 ;[0] + cpi x2, 0xfc ;[1] + brcc bitstuff7 ;[2] + ld shift, y+ ;[3] + dec cnt ;[5] + brne byteloop ;[6] +;make SE0: + cbr x1, USBMASK ;[7] prepare SE0 [spec says EOP may be 21 to 25 cycles] + lds x2, usbNewDeviceAddr;[8] + lsl x2 ;[10] we compare with left shifted address + out USBOUT, x1 ;[11] <-- out SE0 -- from now 2 bits = 22 cycles until bus idle +;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 + subi YL, 2 ;[0] Only assign address on data packets, not ACK/NAK in r0 + sbci YH, 0 ;[1] + 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, 4 ;[11] +se0Delay: + dec x4 ;[12] [15] [18] [21] + brne se0Delay ;[13] [16] [19] [22] + out USBOUT, x1 ;[23] <-- out J (idle) -- end of SE0 (EOP signal) + out USBDDR, x2 ;[24] <-- release bus now + out USBOUT, x3 ;[25] <-- ensure no pull-up resistors are active + rjmp doReturn + |