+++ /dev/null
-/* Name: usbdrvasm128.inc
- * Project: V-USB, virtual USB port for Atmel's(r) AVR(r) microcontrollers
- * Author: Christian Starkjohann
- * Creation Date: 2008-10-11
- * Tabsize: 4
- * Copyright: (c) 2008 by OBJECTIVE DEVELOPMENT Software GmbH
- * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt)
- * This Revision: $Id: usbdrvasm128.inc 758 2009-08-06 10:12:54Z cs $
- */
-
-/* Do not link this file! Link usbdrvasm.S instead, which includes the
- * appropriate implementation!
- */
-
-/*
-General Description:
-This file is the 12.8 MHz version of the USB driver. It is intended for use
-with the internal RC oscillator. Although 12.8 MHz is outside the guaranteed
-calibration range of the oscillator, almost all AVRs can reach this frequency.
-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.
-
-LIMITATIONS
-===========
-Although it may seem very handy to save the crystal and use the internal
-RC oscillator of the CPU, this method (and this module) has some serious
-limitations:
-(1) The guaranteed calibration range of the oscillator is only 8.1 MHz.
-They typical range is 14.5 MHz and most AVRs can actually reach this rate.
-(2) Writing EEPROM and Flash may be unreliable (short data lifetime) since
-the write procedure is timed from the RC oscillator.
-(3) End Of Packet detection (SE0) should be in bit 1, bit it is only checked
-if bits 0 and 1 both read as 0 on D- and D+ read as 0 in the middle. This may
-cause problems with old hubs which delay SE0 by up to one cycle.
-(4) Code size is much larger than that of the other modules.
-
-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!
-
-Implementation notes:
-======================
-min frequency: 67 cycles for 8 bit -> 12.5625 MHz
-max frequency: 69.286 cycles for 8 bit -> 12.99 MHz
-nominal frequency: 12.77 MHz ( = sqrt(min * max))
-
-sampling positions: (next even number in range [+/- 0.5])
-cycle index range: 0 ... 66
-bits:
-.5, 8.875, 17.25, 25.625, 34, 42.375, 50.75, 59.125
-[0/1], [9], [17], [25/+26], [34], [+42/43], [51], [59]
-
-bit number: 0 1 2 3 4 5 6 7
-spare cycles 1 2 1 2 1 1 1 0
-
-operations to perform: duration cycle
- ----------------
- eor fix, shift 1 -> 00
- andi phase, USBMASK 1 -> 08
- breq se0 1 -> 16 (moved to 11)
- st y+, data 2 -> 24, 25
- mov data, fix 1 -> 33
- ser data 1 -> 41
- subi cnt, 1 1 -> 49
- brcs overflow 1 -> 50
-
-layout of samples and operations:
-[##] = sample bit
-<##> = sample phase
-*##* = operation
-
-0: *00* [01] 02 03 04 <05> 06 07
-1: *08* [09] 10 11 12 <13> 14 15 *16*
-2: [17] 18 19 20 <21> 22 23
-3: *24* *25* [26] 27 28 29 <30> 31 32
-4: *33* [34] 35 36 37 <38> 39 40
-5: *41* [42] 43 44 45 <46> 47 48
-6: *49* *50* [51] 52 53 54 <55> 56 57 58
-7: [59] 60 61 62 <63> 64 65 66
-*****************************************************************************/
-
-/* we prefer positive expressions (do if condition) instead of negative
- * (skip if condition), therefore use defines for skip instructions:
- */
-#define ifioclr sbis
-#define ifioset sbic
-#define ifrclr sbrs
-#define ifrset sbrc
-
-/* The registers "fix" and "data" swap their meaning during the loop. Use
- * defines to keep their name constant.
- */
-#define fix x2
-#define data x1
-#undef phase /* phase has a default definition to x4 */
-#define phase x3
-
-
-USB_INTR_VECTOR:
-;order of registers pushed: YL, SREG [sofError], YH, shift, x1, x2, x3, cnt, r0
- 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
-waitForK:
-;The following code results in a sampling window of 1/4 bit which meets the spec.
- sbis USBIN, USBMINUS
- rjmp foundK
- sbis USBIN, USBMINUS
- rjmp foundK
- sbis USBIN, USBMINUS
- rjmp foundK
- sbis USBIN, USBMINUS
- rjmp foundK
- sbis USBIN, USBMINUS ;[0]
- rjmp foundK ;[1]
-#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:
-;{3, 5} after falling D- edge, average delay: 4 cycles [we want 4 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 YH ;[2]
- lds YL, usbInputBufOffset;[4]
- clr YH ;[6]
- subi YL, lo8(-(usbRxBuf));[7]
- sbci YH, hi8(-(usbRxBuf));[8]
-
- sbis USBIN, USBMINUS ;[9] we want two bits K [we want to sample at 8 + 4 - 1.5 = 10.5]
- rjmp haveTwoBitsK ;[10]
- pop YH ;[11] undo the push from before
- rjmp waitForK ;[13] this was not the end of sync, retry
-haveTwoBitsK:
-;----------------------------------------------------------------------------
-; push more registers and initialize values while we sample the first bits:
-;----------------------------------------------------------------------------
-#define fix x2
-#define data x1
-
- push shift ;[12]
- push x1 ;[14]
- push x2 ;[16]
- ldi shift, 0x80 ;[18] prevent bit-unstuffing but init low bits to 0
- ifioset USBIN, USBMINUS ;[19] [01] <--- bit 0 [10.5 + 8 = 18.5]
- ori shift, 1<<0 ;[02]
- push x3 ;[03]
- push cnt ;[05]
- push r0 ;[07]
- ifioset USBIN, USBMINUS ;[09] <--- bit 1
- ori shift, 1<<1 ;[10]
- ser fix ;[11]
- ldi cnt, USB_BUFSIZE ;[12]
- mov data, shift ;[13]
- lsl shift ;[14]
- nop2 ;[15]
- ifioset USBIN, USBMINUS ;[17] <--- bit 2
- ori data, 3<<2 ;[18] store in bit 2 AND bit 3
- eor shift, data ;[19] do nrzi decoding
- andi data, 1<<3 ;[20]
- in phase, USBIN ;[21] <- phase
- brne jumpToEntryAfterSet ;[22] if USBMINS at bit 3 was 1
- nop ;[23]
- rjmp entryAfterClr ;[24]
-jumpToEntryAfterSet:
- rjmp entryAfterSet ;[24]
-
-;----------------------------------------------------------------------------
-; Receiver loop (numbers in brackets are cycles within byte after instr)
-;----------------------------------------------------------------------------
-#undef fix
-#define fix x1
-#undef data
-#define data x2
-
-bit7IsSet:
- ifrclr phase, USBMINUS ;[62] check phase only if D- changed
- lpm ;[63]
- in phase, USBIN ;[64] <- phase (one cycle too late)
- ori shift, 1 << 7 ;[65]
- nop ;[66]
-;;;;rjmp bit0AfterSet ; -> [00] == [67] moved block up to save jump
-bit0AfterSet:
- eor fix, shift ;[00]
-#undef fix
-#define fix x2
-#undef data
-#define data x1 /* we now have result in data, fix is reset to 0xff */
- ifioclr USBIN, USBMINUS ;[01] <--- sample 0
- rjmp bit0IsClr ;[02]
- andi shift, ~(7 << 0) ;[03]
- breq unstuff0s ;[04]
- in phase, USBIN ;[05] <- phase
- rjmp bit1AfterSet ;[06]
-unstuff0s:
- in phase, USBIN ;[06] <- phase (one cycle too late)
- andi fix, ~(1 << 0) ;[07]
- ifioclr USBIN, USBMINUS ;[00]
- ifioset USBIN, USBPLUS ;[01]
- rjmp bit0IsClr ;[02] executed if first expr false or second true
-se0AndStore: ; executed only if both bits 0
- st y+, x1 ;[15/17] cycles after start of byte
- rjmp se0 ;[17/19]
-
-bit0IsClr:
- ifrset phase, USBMINUS ;[04] check phase only if D- changed
- lpm ;[05]
- in phase, USBIN ;[06] <- phase (one cycle too late)
- ori shift, 1 << 0 ;[07]
-bit1AfterClr:
- andi phase, USBMASK ;[08]
- ifioset USBIN, USBMINUS ;[09] <--- sample 1
- rjmp bit1IsSet ;[10]
- breq se0AndStore ;[11] if D- was 0 in bits 0 AND 1 and D+ was 0 in between, we have SE0
- andi shift, ~(7 << 1) ;[12]
- in phase, USBIN ;[13] <- phase
- breq unstuff1c ;[14]
- rjmp bit2AfterClr ;[15]
-unstuff1c:
- andi fix, ~(1 << 1) ;[16]
- nop2 ;[08]
- nop2 ;[10]
-bit1IsSet:
- ifrclr phase, USBMINUS ;[12] check phase only if D- changed
- lpm ;[13]
- in phase, USBIN ;[14] <- phase (one cycle too late)
- ori shift, 1 << 1 ;[15]
- nop ;[16]
-bit2AfterSet:
- ifioclr USBIN, USBMINUS ;[17] <--- sample 2
- rjmp bit2IsClr ;[18]
- andi shift, ~(7 << 2) ;[19]
- breq unstuff2s ;[20]
- in phase, USBIN ;[21] <- phase
- rjmp bit3AfterSet ;[22]
-unstuff2s:
- in phase, USBIN ;[22] <- phase (one cycle too late)
- andi fix, ~(1 << 2) ;[23]
- nop2 ;[16]
- nop2 ;[18]
-bit2IsClr:
- ifrset phase, USBMINUS ;[20] check phase only if D- changed
- lpm ;[21]
- in phase, USBIN ;[22] <- phase (one cycle too late)
- ori shift, 1 << 2 ;[23]
-bit3AfterClr:
- st y+, data ;[24]
-entryAfterClr:
- ifioset USBIN, USBMINUS ;[26] <--- sample 3
- rjmp bit3IsSet ;[27]
- andi shift, ~(7 << 3) ;[28]
- breq unstuff3c ;[29]
- in phase, USBIN ;[30] <- phase
- rjmp bit4AfterClr ;[31]
-unstuff3c:
- in phase, USBIN ;[31] <- phase (one cycle too late)
- andi fix, ~(1 << 3) ;[32]
- nop2 ;[25]
- nop2 ;[27]
-bit3IsSet:
- ifrclr phase, USBMINUS ;[29] check phase only if D- changed
- lpm ;[30]
- in phase, USBIN ;[31] <- phase (one cycle too late)
- ori shift, 1 << 3 ;[32]
-bit4AfterSet:
- mov data, fix ;[33] undo this move by swapping defines
-#undef fix
-#define fix x1
-#undef data
-#define data x2
- ifioclr USBIN, USBMINUS ;[34] <--- sample 4
- rjmp bit4IsClr ;[35]
- andi shift, ~(7 << 4) ;[36]
- breq unstuff4s ;[37]
- in phase, USBIN ;[38] <- phase
- rjmp bit5AfterSet ;[39]
-unstuff4s:
- in phase, USBIN ;[39] <- phase (one cycle too late)
- andi fix, ~(1 << 4) ;[40]
- nop2 ;[33]
- nop2 ;[35]
-bit4IsClr:
- ifrset phase, USBMINUS ;[37] check phase only if D- changed
- lpm ;[38]
- in phase, USBIN ;[39] <- phase (one cycle too late)
- ori shift, 1 << 4 ;[40]
-bit5AfterClr:
- ser data ;[41]
- ifioset USBIN, USBMINUS ;[42] <--- sample 5
- rjmp bit5IsSet ;[43]
- andi shift, ~(7 << 5) ;[44]
- breq unstuff5c ;[45]
- in phase, USBIN ;[46] <- phase
- rjmp bit6AfterClr ;[47]
-unstuff5c:
- in phase, USBIN ;[47] <- phase (one cycle too late)
- andi fix, ~(1 << 5) ;[48]
- nop2 ;[41]
- nop2 ;[43]
-bit5IsSet:
- ifrclr phase, USBMINUS ;[45] check phase only if D- changed
- lpm ;[46]
- in phase, USBIN ;[47] <- phase (one cycle too late)
- ori shift, 1 << 5 ;[48]
-bit6AfterSet:
- subi cnt, 1 ;[49]
- brcs jumpToOverflow ;[50]
- ifioclr USBIN, USBMINUS ;[51] <--- sample 6
- rjmp bit6IsClr ;[52]
- andi shift, ~(3 << 6) ;[53]
- cpi shift, 2 ;[54]
- in phase, USBIN ;[55] <- phase
- brlt unstuff6s ;[56]
- rjmp bit7AfterSet ;[57]
-
-jumpToOverflow:
- rjmp overflow
-
-unstuff6s:
- andi fix, ~(1 << 6) ;[50]
- lpm ;[51]
-bit6IsClr:
- ifrset phase, USBMINUS ;[54] check phase only if D- changed
- lpm ;[55]
- in phase, USBIN ;[56] <- phase (one cycle too late)
- ori shift, 1 << 6 ;[57]
- nop ;[58]
-bit7AfterClr:
- ifioset USBIN, USBMINUS ;[59] <--- sample 7
- rjmp bit7IsSet ;[60]
- andi shift, ~(1 << 7) ;[61]
- cpi shift, 4 ;[62]
- in phase, USBIN ;[63] <- phase
- brlt unstuff7c ;[64]
- rjmp bit0AfterClr ;[65] -> [00] == [67]
-unstuff7c:
- andi fix, ~(1 << 7) ;[58]
- nop ;[59]
- rjmp bit7IsSet ;[60]
-
-bit7IsClr:
- ifrset phase, USBMINUS ;[62] check phase only if D- changed
- lpm ;[63]
- in phase, USBIN ;[64] <- phase (one cycle too late)
- ori shift, 1 << 7 ;[65]
- nop ;[66]
-;;;;rjmp bit0AfterClr ; -> [00] == [67] moved block up to save jump
-bit0AfterClr:
- eor fix, shift ;[00]
-#undef fix
-#define fix x2
-#undef data
-#define data x1 /* we now have result in data, fix is reset to 0xff */
- ifioset USBIN, USBMINUS ;[01] <--- sample 0
- rjmp bit0IsSet ;[02]
- andi shift, ~(7 << 0) ;[03]
- breq unstuff0c ;[04]
- in phase, USBIN ;[05] <- phase
- rjmp bit1AfterClr ;[06]
-unstuff0c:
- in phase, USBIN ;[06] <- phase (one cycle too late)
- andi fix, ~(1 << 0) ;[07]
- ifioclr USBIN, USBMINUS ;[00]
- ifioset USBIN, USBPLUS ;[01]
- rjmp bit0IsSet ;[02] executed if first expr false or second true
- rjmp se0AndStore ;[03] executed only if both bits 0
-bit0IsSet:
- ifrclr phase, USBMINUS ;[04] check phase only if D- changed
- lpm ;[05]
- in phase, USBIN ;[06] <- phase (one cycle too late)
- ori shift, 1 << 0 ;[07]
-bit1AfterSet:
- andi shift, ~(7 << 1) ;[08] compensated by "ori shift, 1<<1" if bit1IsClr
- ifioclr USBIN, USBMINUS ;[09] <--- sample 1
- rjmp bit1IsClr ;[10]
- breq unstuff1s ;[11]
- nop2 ;[12] do not check for SE0 if bit 0 was 1
- in phase, USBIN ;[14] <- phase (one cycle too late)
- rjmp bit2AfterSet ;[15]
-unstuff1s:
- in phase, USBIN ;[13] <- phase
- andi fix, ~(1 << 1) ;[14]
- lpm ;[07]
- nop2 ;[10]
-bit1IsClr:
- ifrset phase, USBMINUS ;[12] check phase only if D- changed
- lpm ;[13]
- in phase, USBIN ;[14] <- phase (one cycle too late)
- ori shift, 1 << 1 ;[15]
- nop ;[16]
-bit2AfterClr:
- ifioset USBIN, USBMINUS ;[17] <--- sample 2
- rjmp bit2IsSet ;[18]
- andi shift, ~(7 << 2) ;[19]
- breq unstuff2c ;[20]
- in phase, USBIN ;[21] <- phase
- rjmp bit3AfterClr ;[22]
-unstuff2c:
- in phase, USBIN ;[22] <- phase (one cycle too late)
- andi fix, ~(1 << 2) ;[23]
- nop2 ;[16]
- nop2 ;[18]
-bit2IsSet:
- ifrclr phase, USBMINUS ;[20] check phase only if D- changed
- lpm ;[21]
- in phase, USBIN ;[22] <- phase (one cycle too late)
- ori shift, 1 << 2 ;[23]
-bit3AfterSet:
- st y+, data ;[24]
-entryAfterSet:
- ifioclr USBIN, USBMINUS ;[26] <--- sample 3
- rjmp bit3IsClr ;[27]
- andi shift, ~(7 << 3) ;[28]
- breq unstuff3s ;[29]
- in phase, USBIN ;[30] <- phase
- rjmp bit4AfterSet ;[31]
-unstuff3s:
- in phase, USBIN ;[31] <- phase (one cycle too late)
- andi fix, ~(1 << 3) ;[32]
- nop2 ;[25]
- nop2 ;[27]
-bit3IsClr:
- ifrset phase, USBMINUS ;[29] check phase only if D- changed
- lpm ;[30]
- in phase, USBIN ;[31] <- phase (one cycle too late)
- ori shift, 1 << 3 ;[32]
-bit4AfterClr:
- mov data, fix ;[33] undo this move by swapping defines
-#undef fix
-#define fix x1
-#undef data
-#define data x2
- ifioset USBIN, USBMINUS ;[34] <--- sample 4
- rjmp bit4IsSet ;[35]
- andi shift, ~(7 << 4) ;[36]
- breq unstuff4c ;[37]
- in phase, USBIN ;[38] <- phase
- rjmp bit5AfterClr ;[39]
-unstuff4c:
- in phase, USBIN ;[39] <- phase (one cycle too late)
- andi fix, ~(1 << 4) ;[40]
- nop2 ;[33]
- nop2 ;[35]
-bit4IsSet:
- ifrclr phase, USBMINUS ;[37] check phase only if D- changed
- lpm ;[38]
- in phase, USBIN ;[39] <- phase (one cycle too late)
- ori shift, 1 << 4 ;[40]
-bit5AfterSet:
- ser data ;[41]
- ifioclr USBIN, USBMINUS ;[42] <--- sample 5
- rjmp bit5IsClr ;[43]
- andi shift, ~(7 << 5) ;[44]
- breq unstuff5s ;[45]
- in phase, USBIN ;[46] <- phase
- rjmp bit6AfterSet ;[47]
-unstuff5s:
- in phase, USBIN ;[47] <- phase (one cycle too late)
- andi fix, ~(1 << 5) ;[48]
- nop2 ;[41]
- nop2 ;[43]
-bit5IsClr:
- ifrset phase, USBMINUS ;[45] check phase only if D- changed
- lpm ;[46]
- in phase, USBIN ;[47] <- phase (one cycle too late)
- ori shift, 1 << 5 ;[48]
-bit6AfterClr:
- subi cnt, 1 ;[49]
- brcs overflow ;[50]
- ifioset USBIN, USBMINUS ;[51] <--- sample 6
- rjmp bit6IsSet ;[52]
- andi shift, ~(3 << 6) ;[53]
- cpi shift, 2 ;[54]
- in phase, USBIN ;[55] <- phase
- brlt unstuff6c ;[56]
- rjmp bit7AfterClr ;[57]
-unstuff6c:
- andi fix, ~(1 << 6) ;[50]
- lpm ;[51]
-bit6IsSet:
- ifrclr phase, USBMINUS ;[54] check phase only if D- changed
- lpm ;[55]
- in phase, USBIN ;[56] <- phase (one cycle too late)
- ori shift, 1 << 6 ;[57]
-bit7AfterSet:
- ifioclr USBIN, USBMINUS ;[59] <--- sample 7
- rjmp bit7IsClr ;[60]
- andi shift, ~(1 << 7) ;[61]
- cpi shift, 4 ;[62]
- in phase, USBIN ;[63] <- phase
- brlt unstuff7s ;[64]
- rjmp bit0AfterSet ;[65] -> [00] == [67]
-unstuff7s:
- andi fix, ~(1 << 7) ;[58]
- nop ;[59]
- rjmp bit7IsClr ;[60]
-
-macro POP_STANDARD ; 14 cycles
- pop r0
- pop cnt
- 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"
-
-;----------------------------------------------------------------------------
-; Transmitting data
-;----------------------------------------------------------------------------
-
-txByteLoop:
-txBitloop:
-stuffN1Delay: ; [03]
- ror shift ;[-5] [11] [63]
- brcc doExorN1 ;[-4] [64]
- subi x3, 1 ;[-3]
- brne commonN1 ;[-2]
- lsl shift ;[-1] compensate ror after rjmp stuffDelay
- nop ;[00] stuffing consists of just waiting 8 cycles
- rjmp stuffN1Delay ;[01] after ror, C bit is reliably clear
-
-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
-
-; USB spec says:
-; idle = J
-; J = (D+ = 0), (D- = 1) or USBOUT = 0x01
-; K = (D+ = 1), (D- = 0) or USBOUT = 0x02
-; Spec allows 7.5 bit times from EOP to SOP for replies (= 60 cycles)
-
-;usbSend:
-;pointer to data in 'Y'
-;number of bytes in 'cnt' -- including sync byte
-;uses: x1...x3, shift, cnt, Y [x1 = mirror USBOUT, x2 = USBMASK, x3 = bitstuff cnt]
-;Numbers in brackets are time since first bit of sync pattern is sent (start of instruction)
-usbSendAndReti:
- in x2, USBDDR ;[-10] 10 cycles until SOP
- ori x2, USBMASK ;[-9]
- sbi USBOUT, USBMINUS ;[-8] prepare idle state; D+ and D- must have been 0 (no pullups)
- out USBDDR, x2 ;[-6] <--- acquire bus
- in x1, USBOUT ;[-5] port mirror for tx loop
- ldi shift, 0x40 ;[-4] sync byte is first byte sent (we enter loop after ror)
- ldi x2, USBMASK ;[-3]
-doExorN1:
- eor x1, x2 ;[-2] [06] [62]
- ldi x3, 6 ;[-1] [07] [63]
-commonN1:
-stuffN2Delay:
- out USBOUT, x1 ;[00] [08] [64] <--- set bit
- ror shift ;[01]
- brcc doExorN2 ;[02]
- subi x3, 1 ;[03]
- brne commonN2 ;[04]
- lsl shift ;[05] compensate ror after rjmp stuffDelay
- rjmp stuffN2Delay ;[06] after ror, C bit is reliably clear
-doExorN2:
- eor x1, x2 ;[04] [12]
- ldi x3, 6 ;[05] [13]
-commonN2:
- nop2 ;[06] [14]
- subi cnt, 171 ;[08] [16] trick: (3 * 171) & 0xff = 1
- out USBOUT, x1 ;[09] [17] <--- set bit
- brcs txBitloop ;[10] [27] [44]
-
-stuff6Delay:
- ror shift ;[45] [53]
- brcc doExor6 ;[46]
- subi x3, 1 ;[47]
- brne common6 ;[48]
- lsl shift ;[49] compensate ror after rjmp stuffDelay
- nop ;[50] stuffing consists of just waiting 8 cycles
- rjmp stuff6Delay ;[51] after ror, C bit is reliably clear
-doExor6:
- eor x1, x2 ;[48] [56]
- ldi x3, 6 ;[49]
-common6:
-stuff7Delay:
- ror shift ;[50] [58]
- out USBOUT, x1 ;[51] <--- set bit
- brcc doExor7 ;[52]
- subi x3, 1 ;[53]
- brne common7 ;[54]
- lsl shift ;[55] compensate ror after rjmp stuffDelay
- rjmp stuff7Delay ;[56] after ror, C bit is reliably clear
-doExor7:
- eor x1, x2 ;[54] [62]
- ldi x3, 6 ;[55]
-common7:
- ld shift, y+ ;[56]
- nop ;[58]
- tst cnt ;[59]
- out USBOUT, x1 ;[60] [00]<--- set bit
- brne txByteLoop ;[61] [01]
-;make SE0:
- cbr x1, USBMASK ;[02] prepare SE0 [spec says EOP may be 15 to 18 cycles]
- lds x2, usbNewDeviceAddr;[03]
- lsl x2 ;[05] we compare with left shifted address
- subi YL, 2 + 0 ;[06] Only assign address on data packets, not ACK/NAK in r0
- sbci YH, 0 ;[07]
- out USBOUT, x1 ;[00] <-- out SE0 -- from now 2 bits = 16 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
- breq skipAddrAssign ;[01]
- sts usbDeviceAddr, x2 ; if not skipped: SE0 is one cycle longer
-skipAddrAssign:
-;end of usbDeviceAddress transfer
- ldi x2, 1<<USB_INTR_PENDING_BIT;[03] int0 occurred during TX -- clear pending flag
- USB_STORE_PENDING(x2) ;[04]
- ori x1, USBIDLE ;[05]
- in x2, USBDDR ;[06]
- cbr x2, USBMASK ;[07] set both pins to input
- mov x3, x1 ;[08]
- cbr x3, USBMASK ;[09] configure no pullup on both pins
- lpm ;[10]
- lpm ;[13]
- out USBOUT, x1 ;[16] <-- out J (idle) -- end of SE0 (EOP signal)
- out USBDDR, x2 ;[17] <-- release bus now
- out USBOUT, x3 ;[18] <-- ensure no pull-up resistors are active
- rjmp doReturn
-
-
-
-/*****************************************************************************
-The following PHP script generates a code skeleton for the receiver routine:
-
-<?php
-
-function printCmdBuffer($thisBit)
-{
-global $cycle;
-
- $nextBit = ($thisBit + 1) % 8;
- $s = ob_get_contents();
- ob_end_clean();
- $s = str_replace("#", $thisBit, $s);
- $s = str_replace("@", $nextBit, $s);
- $lines = explode("\n", $s);
- for($i = 0; $i < count($lines); $i++){
- $s = $lines[$i];
- if(ereg("\\[([0-9-][0-9])\\]", $s, $regs)){
- $c = $cycle + (int)$regs[1];
- $s = ereg_replace("\\[[0-9-][0-9]\\]", sprintf("[%02d]", $c), $s);
- }
- if(strlen($s) > 0)
- echo "$s\n";
- }
-}
-
-function printBit($isAfterSet, $bitNum)
-{
- ob_start();
- if($isAfterSet){
-?>
- ifioclr USBIN, USBMINUS ;[00] <--- sample
- rjmp bit#IsClr ;[01]
- andi shift, ~(7 << #) ;[02]
- breq unstuff#s ;[03]
- in phase, USBIN ;[04] <- phase
- rjmp bit@AfterSet ;[05]
-unstuff#s:
- in phase, USBIN ;[05] <- phase (one cycle too late)
- andi fix, ~(1 << #) ;[06]
- nop2 ;[-1]
- nop2 ;[01]
-bit#IsClr:
- ifrset phase, USBMINUS ;[03] check phase only if D- changed
- lpm ;[04]
- in phase, USBIN ;[05] <- phase (one cycle too late)
- ori shift, 1 << # ;[06]
-<?php
- }else{
-?>
- ifioset USBIN, USBMINUS ;[00] <--- sample
- rjmp bit#IsSet ;[01]
- andi shift, ~(7 << #) ;[02]
- breq unstuff#c ;[03]
- in phase, USBIN ;[04] <- phase
- rjmp bit@AfterClr ;[05]
-unstuff#c:
- in phase, USBIN ;[05] <- phase (one cycle too late)
- andi fix, ~(1 << #) ;[06]
- nop2 ;[-1]
- nop2 ;[01]
-bit#IsSet:
- ifrclr phase, USBMINUS ;[03] check phase only if D- changed
- lpm ;[04]
- in phase, USBIN ;[05] <- phase (one cycle too late)
- ori shift, 1 << # ;[06]
-<?php
- }
- printCmdBuffer($bitNum);
-}
-
-$bitStartCycles = array(1, 9, 17, 26, 34, 42, 51, 59);
-for($i = 0; $i < 16; $i++){
- $bit = $i % 8;
- $emitClrCode = ($i + (int)($i / 8)) % 2;
- $cycle = $bitStartCycles[$bit];
- if($emitClrCode){
- printf("bit%dAfterClr:\n", $bit);
- }else{
- printf("bit%dAfterSet:\n", $bit);
- }
- ob_start();
- echo " ***** ;[-1]\n";
- printCmdBuffer($bit);
- printBit(!$emitClrCode, $bit);
- if($i == 7)
- echo "\n";
-}
-
-?>
-*****************************************************************************/
projects / fnordlicht-mini / blobdiff