Maxim Integrated / OneWire

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Dependents:   MAXREFDES131_Qt_Demo MAX32630FTHR_iButton_uSD_Logger MAX32630FTHR_DS18B20_uSD_Logger MAXREFDES130_131_Demo ... more

OneWire_Masters/GPIO/owlink.s@53:071ae5d090d1, 2016-04-12 (annotated)

Committer:
IanBenzMaxim
Date:
Tue Apr 12 10:51:20 2016 -0500
Revision:
53:071ae5d090d1
Parent:
52:4cba20c21941
Child:
57:1635f247ceae
Added functionality for cross-platform assembly macros. Attempted to switch pin manipulation functions to inline for performance, but this actually doubled the first bit time when tested in IAR. Tweak ow_bit() types to please GCC.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
IanBenzMaxim 52:4cba20c21941 1 // ow_usdelay configuration
IanBenzMaxim 40:590791ecac1c 2 #define PROC_CLOCK_MHZ (__SYSTEM_HFX / 1000000) // Processor clock in MHz
IanBenzMaxim 31:7c684e49fa8f 3 #define OVERHEAD_TUNING 21 // Fraction where OverheadTime(us) = OVERHEAD_TUNING / PROC_CLOCK_MHZ
IanBenzMaxim 31:7c684e49fa8f 4 // Make PROC_CLOCK_MHZ and OVERHEAD_TUNING divisible by PROC_CYCLES_PER_LOOP for best results
IanBenzMaxim 28:057bb14d3cee 5
IanBenzMaxim 52:4cba20c21941 6 // ow_usdelay constants
IanBenzMaxim 31:7c684e49fa8f 7 #define PIPELINE_REFILL_PROC_CYCLES 1 // ARM specifies 1-3 cycles for pipeline refill following a branch
IanBenzMaxim 31:7c684e49fa8f 8 #define PROC_CYCLES_PER_LOOP (2 + PIPELINE_REFILL_PROC_CYCLES)
IanBenzMaxim 31:7c684e49fa8f 9 #define LOOPS_PER_US (PROC_CLOCK_MHZ / PROC_CYCLES_PER_LOOP) // Number of loop passes for a 1 us delay
IanBenzMaxim 31:7c684e49fa8f 10 #define LOOPS_REMOVED_TUNING (OVERHEAD_TUNING / PROC_CYCLES_PER_LOOP)
IanBenzMaxim 46:afe466c96069 11
IanBenzMaxim 52:4cba20c21941 12 // OwTiming offsets
IanBenzMaxim 52:4cba20c21941 13 #define tRSTL_OFFSET 0
IanBenzMaxim 52:4cba20c21941 14 #define tMSP_OFFSET 2
IanBenzMaxim 52:4cba20c21941 15 #define tW0L_OFFSET 4
IanBenzMaxim 52:4cba20c21941 16 #define tW1L_OFFSET 6
IanBenzMaxim 52:4cba20c21941 17 #define tMSR_OFFSET 8
IanBenzMaxim 52:4cba20c21941 18 #define tSLOT_OFFSET 10
IanBenzMaxim 52:4cba20c21941 19
IanBenzMaxim 46:afe466c96069 20 // LABEL macro
IanBenzMaxim 46:afe466c96069 21 #ifdef TOOLCHAIN_GCC_ARM
IanBenzMaxim 46:afe466c96069 22 #define LABEL(x) x:
IanBenzMaxim 46:afe466c96069 23 #else // TOOLCHAIN_IAR or TOOLCHAIN_ARM_STD
IanBenzMaxim 46:afe466c96069 24 #define LABEL(x) x
IanBenzMaxim 46:afe466c96069 25 #endif
IanBenzMaxim 46:afe466c96069 26
IanBenzMaxim 46:afe466c96069 27 // EXPORT_LABEL macro
IanBenzMaxim 46:afe466c96069 28 #ifdef TOOLCHAIN_GCC_ARM
IanBenzMaxim 46:afe466c96069 29 #define EXPORT_LABEL(x) .global x
IanBenzMaxim 46:afe466c96069 30 #else // TOOLCHAIN_IAR or TOOLCHAIN_ARM_STD
IanBenzMaxim 46:afe466c96069 31 #define EXPORT_LABEL(x) EXPORT x
IanBenzMaxim 46:afe466c96069 32 #endif
IanBenzMaxim 46:afe466c96069 33
IanBenzMaxim 46:afe466c96069 34 // THUMB_FUNC macro
IanBenzMaxim 46:afe466c96069 35 #ifdef TOOLCHAIN_GCC_ARM
IanBenzMaxim 46:afe466c96069 36 #define THUMB_FUNC .thumb_func
IanBenzMaxim 46:afe466c96069 37 #else // TOOLCHAIN_IAR or TOOLCHAIN_ARM_STD
IanBenzMaxim 46:afe466c96069 38 #define THUMB_FUNC
IanBenzMaxim 46:afe466c96069 39 #endif
IanBenzMaxim 52:4cba20c21941 40
IanBenzMaxim 53:071ae5d090d1 41 // MACRO_ARM_BEGIN macro
IanBenzMaxim 53:071ae5d090d1 42 #ifdef TOOLCHAIN_ARM_STD
IanBenzMaxim 53:071ae5d090d1 43 #define MACRO_ARM_BEGIN MACRO
IanBenzMaxim 53:071ae5d090d1 44 #else // TOOLCHAIN_IAR or TOOLCHAIN_GCC_ARM
IanBenzMaxim 53:071ae5d090d1 45 #define MACRO_ARM_BEGIN
IanBenzMaxim 53:071ae5d090d1 46 #endif
IanBenzMaxim 53:071ae5d090d1 47
IanBenzMaxim 53:071ae5d090d1 48 // MACRO_BEGIN macro
IanBenzMaxim 53:071ae5d090d1 49 #if defined TOOLCHAIN_IAR
IanBenzMaxim 53:071ae5d090d1 50 #define MACRO_BEGIN(name) name MACRO
IanBenzMaxim 53:071ae5d090d1 51 #elif defined TOOLCHAIN_ARM_STD
IanBenzMaxim 53:071ae5d090d1 52 #define MACRO_BEGIN(name) $label name
IanBenzMaxim 53:071ae5d090d1 53 #else // TOOLCHAIN_GCC_ARM
IanBenzMaxim 53:071ae5d090d1 54 #define MACRO_BEGIN(name) .macro name
IanBenzMaxim 53:071ae5d090d1 55 #endif
IanBenzMaxim 53:071ae5d090d1 56
IanBenzMaxim 53:071ae5d090d1 57 // ENDM macro
IanBenzMaxim 53:071ae5d090d1 58 #if defined TOOLCHAIN_IAR
IanBenzMaxim 53:071ae5d090d1 59 // Use ENDM since IAR processes macros before #define directives.
IanBenzMaxim 53:071ae5d090d1 60 #elif defined TOOLCHAIN_ARM_STD
IanBenzMaxim 53:071ae5d090d1 61 #define ENDM MEND
IanBenzMaxim 53:071ae5d090d1 62 #else // TOOLCHAIN_GCC_ARM
IanBenzMaxim 53:071ae5d090d1 63 #define ENDM .endm
IanBenzMaxim 53:071ae5d090d1 64 #endif
IanBenzMaxim 53:071ae5d090d1 65
IanBenzMaxim 52:4cba20c21941 66 // Define a code section
IanBenzMaxim 31:7c684e49fa8f 67 #if defined TOOLCHAIN_IAR
IanBenzMaxim 30:fdd7a0f82f2f 68 SECTION owlink : CODE
IanBenzMaxim 31:7c684e49fa8f 69 #elif defined TOOLCHAIN_ARM_STD
IanBenzMaxim 29:5c51a17cfbf5 70 AREA owlink, CODE
IanBenzMaxim 31:7c684e49fa8f 71 #else // TOOLCHAIN_GCC_ARM
IanBenzMaxim 31:7c684e49fa8f 72 .syntax unified
IanBenzMaxim 31:7c684e49fa8f 73 .section .text
IanBenzMaxim 30:fdd7a0f82f2f 74 #endif
IanBenzMaxim 28:057bb14d3cee 75
IanBenzMaxim 31:7c684e49fa8f 76 // void ow_usdelay(unsigned int time_us)
IanBenzMaxim 46:afe466c96069 77 THUMB_FUNC
IanBenzMaxim 46:afe466c96069 78 EXPORT_LABEL(ow_usdelay)
IanBenzMaxim 46:afe466c96069 79 LABEL(ow_usdelay)
IanBenzMaxim 40:590791ecac1c 80 cmp R0, #0 // Return if time_us equals zero
IanBenzMaxim 52:4cba20c21941 81 beq ow_usdelay_return
IanBenzMaxim 52:4cba20c21941 82 mov R2, #LOOPS_PER_US
IanBenzMaxim 52:4cba20c21941 83 mul R0, R0, R2
IanBenzMaxim 28:057bb14d3cee 84 sub R0, R0, #LOOPS_REMOVED_TUNING
IanBenzMaxim 46:afe466c96069 85 LABEL(loop)
IanBenzMaxim 28:057bb14d3cee 86 subs R0, R0, #1
IanBenzMaxim 28:057bb14d3cee 87 bne loop
IanBenzMaxim 52:4cba20c21941 88 LABEL(ow_usdelay_return)
IanBenzMaxim 52:4cba20c21941 89 bx R14
IanBenzMaxim 52:4cba20c21941 90
IanBenzMaxim 52:4cba20c21941 91 // static void write_ow_gpio_low(unsigned int * portReg, unsigned int pinMask)
IanBenzMaxim 52:4cba20c21941 92 THUMB_FUNC
IanBenzMaxim 52:4cba20c21941 93 LABEL(write_ow_gpio_low)
IanBenzMaxim 52:4cba20c21941 94 ldr R2, [R0]
IanBenzMaxim 52:4cba20c21941 95 bic R2, R2, R1
IanBenzMaxim 52:4cba20c21941 96 str R2, [R0]
IanBenzMaxim 52:4cba20c21941 97 bx R14
IanBenzMaxim 52:4cba20c21941 98
IanBenzMaxim 52:4cba20c21941 99 // static void write_ow_gpio_high(unsigned int * portReg, unsigned int pinMask)
IanBenzMaxim 52:4cba20c21941 100 THUMB_FUNC
IanBenzMaxim 52:4cba20c21941 101 LABEL(write_ow_gpio_high)
IanBenzMaxim 52:4cba20c21941 102 ldr R2, [R0]
IanBenzMaxim 52:4cba20c21941 103 orr R2, R2, R1
IanBenzMaxim 52:4cba20c21941 104 str R2, [R0]
IanBenzMaxim 52:4cba20c21941 105 bx R14
IanBenzMaxim 52:4cba20c21941 106
IanBenzMaxim 52:4cba20c21941 107 // static unsigned int read_ow_gpio(unsigned int * portReg, unsigned int pinMask)
IanBenzMaxim 52:4cba20c21941 108 THUMB_FUNC
IanBenzMaxim 52:4cba20c21941 109 LABEL(read_ow_gpio)
IanBenzMaxim 52:4cba20c21941 110 ldr R0, [R0]
IanBenzMaxim 52:4cba20c21941 111 and R0, R0, R1
IanBenzMaxim 28:057bb14d3cee 112 bx R14
IanBenzMaxim 28:057bb14d3cee 113
IanBenzMaxim 53:071ae5d090d1 114 // void ow_bit(uint8_t * sendrecvbit, volatile uint32_t * inPortReg, volatile uint32_t * outPortReg, unsigned int pinMask, const OwTiming * timing)
IanBenzMaxim 52:4cba20c21941 115 THUMB_FUNC
IanBenzMaxim 52:4cba20c21941 116 EXPORT_LABEL(ow_bit)
IanBenzMaxim 52:4cba20c21941 117 LABEL(ow_bit)
IanBenzMaxim 52:4cba20c21941 118 push {R4-R8, R14}
IanBenzMaxim 52:4cba20c21941 119 // Retrive extra parameters from stack
IanBenzMaxim 52:4cba20c21941 120 add R6, SP, #24 // Find beginning of stack: 6 scratch registers * 4 bytes each
IanBenzMaxim 52:4cba20c21941 121 ldr R6, [R6] // Load timing struct
IanBenzMaxim 52:4cba20c21941 122 ldrh R4, [R6, #tSLOT_OFFSET]
IanBenzMaxim 52:4cba20c21941 123 ldrh R5, [R6, #tMSR_OFFSET]
IanBenzMaxim 52:4cba20c21941 124 // R0: sendrecvbit
IanBenzMaxim 52:4cba20c21941 125 // R1: inPortReg
IanBenzMaxim 52:4cba20c21941 126 // R2: outPortReg
IanBenzMaxim 52:4cba20c21941 127 // R3: pinMask
IanBenzMaxim 52:4cba20c21941 128 // R4: tSLOT
IanBenzMaxim 52:4cba20c21941 129 // R5: tMSR
IanBenzMaxim 52:4cba20c21941 130 // R6: timing
IanBenzMaxim 52:4cba20c21941 131 // R7: Scratch
IanBenzMaxim 52:4cba20c21941 132 // R8: Scratch
IanBenzMaxim 52:4cba20c21941 133 // R14: Scratch
IanBenzMaxim 52:4cba20c21941 134
IanBenzMaxim 52:4cba20c21941 135 // Reorganize registers for upcoming function calls
IanBenzMaxim 52:4cba20c21941 136 mov R8, R1 // inPortReg to R8
IanBenzMaxim 52:4cba20c21941 137 mov R7, R2 // outPortReg to R7
IanBenzMaxim 52:4cba20c21941 138 mov R1, R3 // pinMask to R1
IanBenzMaxim 52:4cba20c21941 139 mov R3, R0 // sendrecvbit to R3
IanBenzMaxim 52:4cba20c21941 140 // R0: Scratch
IanBenzMaxim 52:4cba20c21941 141 // R1: pinMask
IanBenzMaxim 52:4cba20c21941 142 // R2: Scratch
IanBenzMaxim 52:4cba20c21941 143 // R3: sendrecvbit
IanBenzMaxim 52:4cba20c21941 144 // R4: tSLOT
IanBenzMaxim 52:4cba20c21941 145 // R5: tMSR
IanBenzMaxim 52:4cba20c21941 146 // R6: timing
IanBenzMaxim 52:4cba20c21941 147 // R7: outPortReg
IanBenzMaxim 52:4cba20c21941 148 // R8: inPortReg
IanBenzMaxim 52:4cba20c21941 149 // R14: Scratch
IanBenzMaxim 52:4cba20c21941 150
IanBenzMaxim 52:4cba20c21941 151 // if (*sendrecvbit & 1)
IanBenzMaxim 52:4cba20c21941 152 ldrb R14, [R3]
IanBenzMaxim 52:4cba20c21941 153 tst R14, #1
IanBenzMaxim 52:4cba20c21941 154 beq write_zero
IanBenzMaxim 52:4cba20c21941 155 ldrh R6, [R6, #tW1L_OFFSET] // tW1L
IanBenzMaxim 52:4cba20c21941 156 sub R4, R4, R5 // tREC = tSLOT - tMSR
IanBenzMaxim 52:4cba20c21941 157 sub R5, R5, R6 // delay2 = tMSR - tLW1L
IanBenzMaxim 52:4cba20c21941 158 // R0: Scratch
IanBenzMaxim 52:4cba20c21941 159 // R1: pinMask
IanBenzMaxim 52:4cba20c21941 160 // R2: Scratch
IanBenzMaxim 52:4cba20c21941 161 // R3: sendrecvbit
IanBenzMaxim 52:4cba20c21941 162 // R4: tREC
IanBenzMaxim 52:4cba20c21941 163 // R5: delay2
IanBenzMaxim 52:4cba20c21941 164 // R6: tW1L
IanBenzMaxim 52:4cba20c21941 165 // R7: outPortReg
IanBenzMaxim 52:4cba20c21941 166 // R8: inPortReg
IanBenzMaxim 52:4cba20c21941 167 // R14: Scratch
IanBenzMaxim 52:4cba20c21941 168 mov R0, R7 // outPortReg
IanBenzMaxim 52:4cba20c21941 169 bl write_ow_gpio_low // Pull low
IanBenzMaxim 52:4cba20c21941 170 mov R0, R6 // tLOW
IanBenzMaxim 52:4cba20c21941 171 bl ow_usdelay // Delay for tLOW
IanBenzMaxim 52:4cba20c21941 172 mov R0, R7 // outPortReg
IanBenzMaxim 52:4cba20c21941 173 bl write_ow_gpio_high // Release pin
IanBenzMaxim 52:4cba20c21941 174 mov R0, R5 // delay2
IanBenzMaxim 52:4cba20c21941 175 bl ow_usdelay // Delay for sample time
IanBenzMaxim 52:4cba20c21941 176 mov R0, R8 // inPortReg
IanBenzMaxim 52:4cba20c21941 177 bl read_ow_gpio // Read pin
IanBenzMaxim 52:4cba20c21941 178 mov R5, R0 // Store read value for later
IanBenzMaxim 52:4cba20c21941 179 b recovery_delay
IanBenzMaxim 52:4cba20c21941 180 // else
IanBenzMaxim 52:4cba20c21941 181 LABEL(write_zero)
IanBenzMaxim 52:4cba20c21941 182 ldrh R6, [R6, #tW0L_OFFSET] // tW0L
IanBenzMaxim 52:4cba20c21941 183 sub R4, R4, R6 // tREC = tSLOT - tLW0L
IanBenzMaxim 52:4cba20c21941 184 sub R6, R6, R5 // delay2 = tW0L - tMSR
IanBenzMaxim 52:4cba20c21941 185 // R0: Scratch
IanBenzMaxim 52:4cba20c21941 186 // R1: pinMask
IanBenzMaxim 52:4cba20c21941 187 // R2: Scratch
IanBenzMaxim 52:4cba20c21941 188 // R3: sendrecvbit
IanBenzMaxim 52:4cba20c21941 189 // R4: tREC
IanBenzMaxim 52:4cba20c21941 190 // R5: tMSR
IanBenzMaxim 52:4cba20c21941 191 // R6: delay2
IanBenzMaxim 52:4cba20c21941 192 // R7: outPortReg
IanBenzMaxim 52:4cba20c21941 193 // R8: inPortReg
IanBenzMaxim 52:4cba20c21941 194 // R14: Scratch
IanBenzMaxim 52:4cba20c21941 195 mov R0, R7 // outPortReg
IanBenzMaxim 52:4cba20c21941 196 bl write_ow_gpio_low // Pull low
IanBenzMaxim 52:4cba20c21941 197 mov R0, R5 // tMSR
IanBenzMaxim 52:4cba20c21941 198 bl ow_usdelay // Delay for tMSR
IanBenzMaxim 52:4cba20c21941 199 mov R0, R8 // inPortReg
IanBenzMaxim 52:4cba20c21941 200 bl read_ow_gpio // Read pin
IanBenzMaxim 52:4cba20c21941 201 mov R5, R0 // Store read value for later
IanBenzMaxim 52:4cba20c21941 202 mov R0, R6 // delay2
IanBenzMaxim 52:4cba20c21941 203 bl ow_usdelay // Delay for release
IanBenzMaxim 52:4cba20c21941 204 mov R0, R7 // outPortReg
IanBenzMaxim 52:4cba20c21941 205 bl write_ow_gpio_high // Release pin
IanBenzMaxim 52:4cba20c21941 206 // endif (*sendrecvbit & 1)
IanBenzMaxim 52:4cba20c21941 207 // R0: Scratch
IanBenzMaxim 52:4cba20c21941 208 // R1: pinMask
IanBenzMaxim 52:4cba20c21941 209 // R2: Scratch
IanBenzMaxim 52:4cba20c21941 210 // R3: sendrecvbit
IanBenzMaxim 52:4cba20c21941 211 // R4: tREC
IanBenzMaxim 52:4cba20c21941 212 // R5: read value
IanBenzMaxim 52:4cba20c21941 213 // R6: Scratch
IanBenzMaxim 52:4cba20c21941 214 // R7: outPortReg
IanBenzMaxim 52:4cba20c21941 215 // R8: inPortReg
IanBenzMaxim 52:4cba20c21941 216 // R14: Scratch
IanBenzMaxim 52:4cba20c21941 217
IanBenzMaxim 52:4cba20c21941 218 LABEL(recovery_delay)
IanBenzMaxim 52:4cba20c21941 219 mov R0, R4
IanBenzMaxim 52:4cba20c21941 220 bl ow_usdelay // Delay for tREC
IanBenzMaxim 52:4cba20c21941 221
IanBenzMaxim 52:4cba20c21941 222 strb R5, [R3]
IanBenzMaxim 52:4cba20c21941 223 pop {R4-R8, R14}
IanBenzMaxim 52:4cba20c21941 224 bx R14
IanBenzMaxim 31:7c684e49fa8f 225 #ifdef TOOLCHAIN_GCC_ARM
IanBenzMaxim 31:7c684e49fa8f 226 .end
IanBenzMaxim 31:7c684e49fa8f 227 #else // TOOLCHAIN_IAR or TOOLCHAIN_ARM_STD
IanBenzMaxim 31:7c684e49fa8f 228 END
IanBenzMaxim 40:590791ecac1c 229 #endif