A Blue Pill LMT01 Temperature Sensor¶
This is a rewrite of the previous LMT01 temperature sensor project. It now uses fixed point arithmetic to calculate the temperature to one decimal place and has some extra features such as USB/USART2 terminal access, and a MCU “Device Electronic Signature” reader etc.
It contains a ready to run binary for a 64KB Flash version of the STM32F103 Cortex-M3 MCU as used in the Blue Pill that boots from USB at power up.
Connect the few components shown in the schematic below to read the temperature. It runs fine without them but should complain about a missing sensor if you try to read the temperature.
USB¶
This uses the Mecrisp-Stellaris USB driver for STM32F103 by Jean-Claude Wippler which is based on the Coreforth USB driver by Eckhart Köppen.
Note
From Viktor Dvořák. USB needs PC side idVendor = 0x0483 idProduct = 0x7540 driver which is STM32 Virtual COM port driver desribed in en.DM00478229.pdf. The driver is en.stsw-stm32102.zip (24755 kB) is available directly from st.com
Connect the “Blue Pill” USB port to PC and look for “<Mecrisp STM32F10x Forth Serial Port>” device in your system
Connect a PC serial terminal to the USB device above, you can choose any Baud Rate.
Note
The USB terminal can switch to USART2 by entering “-usb”. Speed is 460800 Baud.
USART2¶
Connect a serial terminal to read the temperature.
USART2 |
MCU Signal |
3.3v/USB Dongle |
|---|---|---|
PA1 |
RTS |
CTS |
PA2 |
TX |
RX |
PA3 |
RX |
TX |
Note
The USART2 terminal can switch to USB by entering “+usb”
Screenshot¶
read the temperature by entering “C” or “F” in the terminal.
check the mcu signature by entering “stm32id”
examine the contents of the RCC CR register by entering “rcc_cr.”
read the remperature by pressing the PA0 pushbutton
Instructions¶
Flash the ae9236b921613c07b1967f21ff20ee97.bin image in this tarball to your STM32F103RBT6 (128KB Flash version) board.
Download it here: https://sourceforge.net/projects/mecrisp-stellaris-folkdoc/files/ae9236b921613c07b1967f21ff20ee97.tar.gz/download
Connect up the few components as shown in the schematic below and power up the board.
The temperature may be read on the terminal by pressing the pushbutton, or entering “T” in the terminal.
The Board runs at 72 MHz using the on board 8MHz crystal.
Schematic¶
Note
Press “C” or “F” for temperature reading, not “C” as shown below on this earlier version schematic.
Blue Pill Layout¶
Layout contributed by Michael Jeffery.
Tarball Contents¶
ae9236b921613c07b1967f21ff20ee97.tar.gz
.
├── ae9236b921613c07b1967f21ff20ee97.DELETE.sh
├── ae9236b921613c07b1967f21ff20ee97.README.md
├── ae9236b921613c07b1967f21ff20ee97.bin
├── ae9236b921613c07b1967f21ff20ee97.flashme
├── ae9236b921613c07b1967f21ff20ee97.words4.txt
├── f103-lmt01.jpeg
├── image.bin
└── lmt01-blue-pill-layout-1.jpg
Source Code¶
This source code by itself won’t run the temperature sensor, however that’s no problem as all the support Words required are installed in the downloadable ready to run image above. Nothing else is required, just enter “C” or “F” in the terminal or press the push button to read the temperature.
Source Code¶
1 \ Program Name: f103-lmt01.fs 2 \ Date: Fri 1 Nov 2019 21:02:00 AEDT 3 \ Copyright 2019 by t.j.porter <terry@tjporter.com.au>, licensed under the GPLV2 4 \ This program may require preloaded support files 5 \ For Mecrisp-Stellaris by Matthias Koch. 6 \ https://sourceforge.net/projects/mecrisp/ 7 \ Chip: STM32F103RBT6, Board: Olimex P103 8 \ Clock: 8 Mhz using the internalRC clock, unless otherwise stated 9 \ All register names are CMSIS-SVD compliant 10 \ Note: gpio a,b,c,d,e, and uart1 are enabled by Mecrisp-Stellaris Core. 11 \ Requires preloaded support program(s): 12 \ Standalone: no preloaded support files required 13 \ 14 \ This Program : Texas Instruments LMT01 temperature sensor reader for 128KB STM32F103 MCU 15 \ Prints DegC and DegF seperately via terminal or together when Push Button (PB0) is pressed. 16 \ Uses Fixed Point Maths: https://mecrisp-stellaris-folkdoc.sourceforge.io/fixed-point.html?highlight=fixed 17 \ 18 \ Clock is set to 72MHz in upload.main.sh for faster uploading 19 \ ---------------------------------------------------------------------------\ 20 \ LMT01: Output Transfer Function: Temp (C) = ((count/4096) *256) -50 21 \ Temperature (°C) Number of pulses 22 \ -49.9375 1 23 \ -49.875 2 24 \ -40 160 25 \ -20 480 26 \ 0 800 27 \ 30 1280 28 \ 50 1600 29 \ 100 2400 30 \ 150 3200 31 \ 32 \ ---------------------------------------------------------------------------\ 33 \ GPIO Description 34 \ ---- ----------- 35 \ PA0 Wake Up PB, normally low : irq$ = 6 36 \ PC12 LED ( open drain to led cathode): not used here 37 \ PB12 Count input : irq# = 40 38 \ PB13 LMT01-1 Activate 39 \ ---------------------------------------------------------------------------\ 40 compiletoram 41 \ compiletoflash 42 43 \ Variables 44 0 variable count.lmt01 45 46 47 \ GPIO Words 48 : GPIOB_CRH_MODE13 ( %XX -- ) 20 lshift GPIOB_CRH bis! ; \ GPIOB_CRH_MODE13 Port n.13 mode bits 49 : GPIOB_CRH_CNF13 ( %XX -- ) 22 lshift GPIOB_CRH bic! ; \ GPIOB_CRH_CNF13 Port n.13 configuration bits 50 : GPIOB_BSRR_BS13 %1 13 lshift GPIOB_BSRR bis! ; \ GPIOB_BSRR_BS13 Set bit 13 51 : GPIOB_BSRR_BR13 %1 29 lshift GPIOB_BSRR bis! ; \ GPIOB_BSRR_BR13 Reset bit 13 52 : GPIOA_CRL_CNF0 ( %XX -- ) 2 lshift GPIOA_CRL bis! ; \ GPIOA_CRL_CNF0 Port n.0 configuration bits 53 : GPIOA_BRR_BR0 %1 0 lshift GPIOA_BRR bis! ; \ GPIOA_BRR_BR0 Reset bit 0 54 55 \ Interrupt Words for LMT01 on PB12, falling trigger. Interrupt #40 56 : AFIO_EXTICR4_EXTI12 ( %XXXX -- ) 0 lshift AFIO_EXTICR4 bis! ; \ AFIO_EXTICR4_EXTI12 EXTI12 configuration 57 : line.12.unmask %1 12 lshift EXTI_IMR bis! ; \ EXTI_IMR_MR12 Interrupt Mask on line 12 58 : line.12.mask %1 12 lshift EXTI_IMR bic! ; \ EXTI_IMR_MR12 Interrupt Mask on line 12 59 : EXTI_RTSR_TR12 %1 12 lshift EXTI_RTSR bis! ; \ EXTI_RTSR_TR12 Rising trigger line 12 60 : EXTI_FTSR_TR12 %1 12 lshift EXTI_FTSR bis! ; \ EXTI_FTSR_TR12 Falling trigger line 12 61 : EXTI_PR_PR12 %1 12 lshift EXTI_PR bis! ; \ EXTI_PR_PR12 Pending bit 12 62 : NVIC_ISER1_SETENA ( %XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX -- ) 0 lshift NVIC_ISER1 bis! ; \ NVIC_ISER1_SETENA SETENA 63 64 \ Interrupt for PB on PA0 falling edge as trigger. Interrupt #6 65 : AFIO_EXTICR1_EXTI0 ( %XXXX -- ) 0 lshift AFIO_EXTICR1 bis! ; \ EXTI0 configuration 66 : line.0.unmask %1 0 lshift EXTI_IMR bis! ; \ EXTI_IMR_MR0 Interrupt Mask on line 0 67 : line.0.mask %1 0 lshift EXTI_IMR bic! ; \ EXTI_IMR_MR0 Interrupt Mask on line 0 68 : EXTI_RTSR_TR0 %1 0 lshift EXTI_RTSR bis! ; \ EXTI_RTSR_TR0 Rising trigger line 0 69 : EXTI_PR_PR0 %1 0 lshift EXTI_PR bis! ; \ EXTI_PR_PR0 Pending bit 0 70 : NVIC_ISER0_SETENA ( %XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX -- ) 0 lshift NVIC_ISER0 bis! ; \ NVIC_ISER0_SETENA SETENA 71 72 \ General Words 73 : >s31.32 ( u -- s31.32 ) 0 swap ; \ convert integer to a Fixed Point s31.32 number 74 : nvic-priority ( priority irq# -- ) 75 $E000E400 + c! 76 ; 77 78 : pa0.pulldown ( -- ) \ PA0 is read temperature pushbutton, triggered when pulled high, so add pulldown. 79 \ 3 2 1 0 80 \ CNF0 MOD0 81 \ 0 1 0 0 default input, floating 82 \ 1 0 0 0 wanted %10 constant cnf.input.pull.up.down 83 2 bit GPIOA_CRL bic! \ clear bit 2 84 3 bit GPIOA_CRL bis! \ set bit 3 85 GPIOA_BRR_BR0 \ with F103, pulldown enabled setting output bit to low 86 ; 87 88 : pb13->output ( -- ) 89 \ 23 22 21 20 90 \ CNF13 MODE13 91 \ 0 1 1 1 92 %11 GPIOB_CRH_MODE13 \ set both mode bits in output mode 50 93 %11 GPIOB_CRH_CNF13 \ clear both bits = push/pull in output mode 94 ; 95 96 : lmt01.power.on ( -- ) 97 GPIOB_BSRR_BS13 98 ; 99 100 : lmt01.power.off ( -- ) 101 GPIOB_BSRR_BR13 102 ; 103 104 : lmt01-fault? ( -- ) count.lmt01 @ 0 = ; \ if count.lmt01 >0, no error 105 106 : lmt01.interrupt.handler ( -- ) 107 line.12.mask \ prevent line.12 retriggering until fully handled 108 EXTI_PR_PR12 \ clear trigger on line 12 109 1 count.lmt01 +! \ increment count.lmt01 by one 110 line.12.unmask \ line.12 can be retriggered now 111 ; 112 113 : lmt01.interrupt.init ( #40 ) 114 1 AFIO_EXTICR4_EXTI12 \ line PB12 115 line.12.unmask 116 EXTI_FTSR_TR12 \ falling trigger on line 12 117 ['] lmt01.interrupt.handler irq-exti10 ! \ link exti10 ( to pb.interrupt.handler 118 %100000000 NVIC_ISER1_SETENA \ enable enterrupt #40 119 ; 120 121 : read.lmt01 ( lmt01 -- count ) \ read sensor, power on, delay, power off 122 0 count.lmt01 ! 123 ms.counter.reset 124 lmt01.power.on 125 100 ms.delay 126 lmt01.power.off 127 lmt01-fault? if \ count window has ended, if no counts there has been an error. 128 ." LMT01 FAULTY OR NOT PRESENT ! " 129 else 130 count.lmt01 @ 131 then 132 line.0.unmask \ pb.interrupt may now be triggered again 133 ; 134 135 : convert.count.to.degrees.c ( count -- degC ) \ convert count.lmt01 to deg C 136 >s31.32 \ Temp (C) = ((count.lmt01/4096) *256) -50 137 4096,0 f/ 256,0 f* 50,0 d- 138 ; 139 140 : convert.count.to.degrees.f ( -- ) 141 convert.count.to.degrees.c 142 1,8 f* 32 >s31.32 d+ \ °F = °C * 1.8000 + 32.00 143 144 ; 145 146 : C ( -- ) \ Deg C print shortcut 147 read.lmt01 148 convert.count.to.degrees.c 149 2 f.n ." C " cr 150 ; 151 152 : F ( c -- ) \ Deg F print shortcut. 153 read.lmt01 154 convert.count.to.degrees.f 155 2 f.n ." F " cr 156 ; 157 158 : pb.interrupt.handler ( -- ) 159 line.0.mask \ prevent retriggering until fully handled 160 EXTI_PR_PR0 \ clear trigger 161 C F cr \ read temperatures 162 ; 163 164 : pb.interrupt.init ( #6 ) 165 0 AFIO_EXTICR1_EXTI0 \ line PA0 166 line.0.unmask \ unmask line 0 167 EXTI_RTSR_TR0 \ rising trigger in line 0 168 ['] pb.interrupt.handler irq-exti0 ! \ link exti0 to pb.interrupt.handler 169 %1000000 NVIC_ISER0_SETENA \ enable interrupt #6 170 ; 171 172 : interrupt.priorities ( -- ) \ highest number is lowest priority 173 100 40 nvic-priority \ lmt01 sensor pulse detect 174 200 6 nvic-priority \ pushbutton 175 ; 176 177 : init ( -- ) 178 72mhz 179 interrupt.priorities 180 systick.init 181 lmt01.interrupt.init 182 pb.interrupt.init 183 pa0.pulldown 184 pb13->output 185 ; 186 187 init 188 189 compiletoram 190 191 192 \ Screenshots 193 \ 194 \ c 35,68 C 195 \ ok. 196 \ f 96,23 F 197 \ ok. 198 \ press button 199 \ 35,68 C 200 \ 96,34 F 201 \ 202 \ 35,68 C 203 \ 96,34 F 204 \ 205 \ read.lmt01 . 1371 ok. <-- raw count @ 35,68 C = 96,34 F 206
Play With Forth ?¶
This Image is a complete system, it contains the compiler and many internal Peripheral registers, see the ae9236b921613c07b1967f21ff20ee97.words4.txt file for a listing of what’s there.
Wonder what they all mean ? see the Dictionary.
You can read, write and examine registers, run programs, even commit them to Flash memory.
Note
to erase all the Flash except the default Mecrisp-Stellaris Forth system, enter “eraseflash” at the terminal. This will remove everything from this project including the USB, and only USART2 will work with a terminal. To reinstall everything just reflash the ae9236b921613c07b1967f21ff20ee97.bin imahe to your board.
