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Forum Index : Microcontroller and PC projects : ArmmiteF4 CSUBs and LCD drivers
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disco4now Guru  Joined: 18/12/2014 Location: AustraliaPosts: 843 |
CSUBs ArmmiteF4 This post covers CSUBs on the ArmmiteF4.It is mostly derived from information in the CMM2 CSUBs thread and a bit of trial and error. The examples from the CMM2 compile for the ArmmiteF4 with just the change of the compiler options. A bitbanged SPI driver for the ST7789 240x240 1.3" IPS display was developed and this highlighted the need for a few changes in the ARMF4CFunctions.h header file used to access the internal MMBasic functions. Relevant information from the CMM2 thread is repeated here so this is a complete reference for the ArmmiteF4. Setting Up the Development Environment GCC ARM compiler To use Cfunctions (CSUBs) you need to install the GCC ARM compiler Select gcc-arm-none-eabi-9-2020-q2-update-win32.exe which is down the page a little bit as it is known to work. The ARMMite F4 uses the same compiler options as the CMM2 except -mcpu=cortex-m7 is replaced by -mcpu=cortex-m4 e.g.  ARMF4CFunctions.h The ARMF4CFunctions.h file needed a few changes to overcome some compile errors and to force the correct calculation of the addresses when calling the inbuilt MMBasic functions. The updated version is included in the Installation file zip below. It is added separately here as it is all you need along with the changed command line parameter if you are already setup for CMM2 CSUBs.ARMF4CFunctions.zip The required linker file is the same one used for CMM2 arm-gcc-link.zip It is included in the Installation file zip below. ARMCFGENV143.BAS To convert the .elf file to the Basic CSUB code the MMBASIC for DOS program armcfgenV143.bas is used. This armcfgenV143.bas can be used, although I have included a slightly modified version that accepts the filename and mode on the command line and allows the function names to be up to 60 characters long in the Installation files zip below. The Installation Files This zip file contains all the required files other than the GCC ARM compiler. Just unzip in a suitable directory and follow the directions in the readme.txt file. Includes ARMCFGENV143a.BAS,arm-gcc-link.ld,ARMF4CFunctions.h and several batch files. ARMMITECSUBS.zip Creating/Editting main.c You create your CSUB by editting the main.c file. This can be done with any text editor, however it is much easier to install STM32CubeIDE and use this to create the main.c and even test compile it to remove any errors before you attempt to create the CSUB. STM32CubeIDE can be downloaded from here I use version 1.6.0 You will need to register but it is free. This zip myF4CSUBS.zip contains a project myF4CSUBS you can import into STM32CubeIDE to get you started. Some things learned while developing the LCDPANEL driver ARMCFunctions.h changes 16 Bit Instructions This quote from the CMM2 thread explains why you might need to pad a function with NOP(); Address of Functions As discussed around page 5 on the CMM2 thread there is an issue when getting the address of a function. @epsilon has provided a solution. For LCDPANEL drivers we need to get the address of the functions when reassigning the vectors for DrawBitmapVector = (unsigned int)&DrawBitmapSPI; DrawRectangleVector = (unsigned int)&DrawRectangleSPI; As suggest by @epsilon setting the functions to static will allow their address to be found. The address returned is the actual loaded address and does not need to be adjusted with the offset to where the CSUB is loaded. * ***** MUST BE static void for the ARMMITEF4 ********** * ------------------------------------------------------ * **********************************************************************/ static void DrawBitmapSPI(int x1, int y1, int width, int height, int scale, int fc, int bc, unsigned char *bitmap){ * ***** MUST BE static void for the ARMMITEF4 ********** * ------------------------------------------------------ * *********************************************************************/ static void DrawRectangleSPI(int x1, int y1, int x2, int y2, int c){ getFPC Function NOT required The use of function getFPC to determine where the CSUB is loaded used on the PIC32 does not work for the ARMMite F4 (and the CMM2 I suspect). It always returns 0. It is however not required because with the ARMMiteF4 the actual loaded address of the function is returned in any case. /* ********************************************************************** * This function (getFPC) does NOT work and is also NOT required for ARMMITE F4 * It is shown here to document this fact. Do NOT include it. * ********************************************************************/ // __attribute__((noinline)) void getFPC(void *a, void *b, volatile unsigned int *c) // { // *c = (unsigned int) (__builtin_return_address (0) - (b -a) - 1) ; // } Printing a string A string declared with static const char as below also seems to return it location using its actual loaded address.e.g. static const char startup[]="ST7789 driver bitbanged SPI loaded\r\n"; p_string(startup); The function p_string() does not need to work out an offset to where the CSUB is loaded. All we need because the string pointer is the real address is. void p_string(const char *s){ char * testData = ( char *)((void *)s ); MMPrintString(testData); } Accessing Options Structure The Option Macro that requires the syntax of Option->LCD_CS gave errors, the Option Macro in the header file was changed and now the syntax Option.LCD_CS seems to give access to the options structure without any errors. #define Option (*(struct option_s *)(unsigned int)Vector_Option) Dummy Function to Document the CSUB In the driver for the ST7789 I have included as the first function a dummy function for the purpose of documentation. The symbols$() string length in armcfgenV143a.bas has been increased to allow up to 60 characters. (currently only 31 allowed.) Can be omitted if you don't want to use it.I find it handy if you have various versions of a driver. e.g. different SPI pins etc LCDPANEL Driver Details *************************************************************** Here is again a list of Peters (old but useful) tutorials for CFunctions (for Micromites!): CFunctions - learning by example (1) CFunctions - learning by example (2) CFunctions - learning by example (3) CFunctions - learning by example (4) ********************************************************************** OPTION LCDPANEL DISABLE before ST7789 Driver The ST7789 driver will not assign the SPI pins if they are reserved. You must ensure you have issued an OPTION LCDPANEL DISABLE before the ST7789 driver is loaded to ensure that the SPI pins are released when TOUCH is disabled. Once the ST7789 driver is loaded and the LCDPANEL is changed to USER then the OPTION LCDPANEL DISABLE will not release the TOUCH pins. OPTION RESET can be used to get to a known state where OPTION DISABLE will remove the TOUCH. This file contains the source for the ST7789 bitbanged driver and the MMBasic test program. ST7789Driver.zip Latest F4 Latest H7 |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 8566 |
Great post  Trivial issue. Compuiler option should be -mfpu=fpv4-d16 for the M4 |
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| disco4now Guru Joined: 18/12/2014 Location: AustraliaPosts: 843 |
UPDATE to COMMANDLINE The correct -mfpu parameter for the commandline -mfpu=fvp4-sp-d16 is now updated , command line for ArmmiteF4 now looks like this.  The install files now have the correct parameters included. ARMMITECSUBS.zip and the STM32CubeIDE project also now has correct parameter. myF4CSUBS.zip Latest F4 Latest H7 |
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| TrevorH Senior Member  Joined: 06/04/2018 Location: United KingdomPosts: 142 |
Are the IO pins on the FSMC connector available to CSUBS? I would like to try using a 16bit CPLD screen with the ArmmiteF407 as I have a couple of 7" versions to use. I can't try these using a basic driver as pins not available. Is there any reason why these can't be made available if NOT using a TFT? Trevor |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5705 |
The FSMC pins aren't GPIO pins. They are, basically, just the internal data bus and some address decoding. The display is effectively just hung off the internal bus like the RAM, flash and CPU. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 8566 |
Yes they are. I just chose not to allow the flexibility to make them available through MMBasic as it is extra code and the F4 is very tight on space |
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| TrevorH Senior Member Joined: 06/04/2018 Location: United KingdomPosts: 142 |
@matherp, I thought so as the exel pinout sheet suggests as much. are thes pins available to CSUBS but NOT MMbasic? Trevor |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 8566 |
Yes, if you use direct register addressing. |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5705 |
Interesting - I'll try to find the source of my information again. Someone had asked a similar question on another forum. Once again, it may have been a choice not to implement them. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| TrevorH Senior Member Joined: 06/04/2018 Location: United KingdomPosts: 142 |
@matherp, could you please give me an example? Trevor |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5705 |
I understood that FSMC (flexible static memory controller) is a specialised high speed static RAM interface, which would imply that there wouldn't be the normal latches etc. that you'd associate with GPIO pins. ST link Edited 2023-11-26 01:35 by Mixtel90 Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 8566 |
They are normal I/O pins and FSMC is just an alternate function. I do know what I'm talking about on this one  Edited 2023-11-26 01:49 by matherp |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5705 |
Cool!  Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| TrevorH Senior Member Joined: 06/04/2018 Location: United KingdomPosts: 142 |
@matherp, Do you mean using the arm's port numbers ie: PE02,PE03 etc or something else. I understand the FSMC pin numbers are probably not needed. Trevor. |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5705 |
The FSC pins will be controlled by the values in a set of registers. MMBasic hasn't got a way to address those pins (yet) so you need to talk to the registers directly. You'd need to look at the chip data to see which registers and how to configure them. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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