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Forum Index : Microcontroller and PC projects : PIO Assembler
| Author | Message | ||||
| ville56 Senior Member  Joined: 08/06/2022 Location: AustriaPosts: 221 |
I want to dive a bit into the PIO stuff and thus was trying out some of the examples from the WebMite manual. Some basic things work but i cannot get the instruction PIO ASSEMBLE 1,"SET PIN 1" to work. I receive a syntax error. Is there any current documentation on the pio assembler available? I found Vollhout's excellent post "PIO explained" but i want to use the mnemonics wherever possible. Thanks, Gerald 73 de OE1HGA, Gerald |
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| Volhout Guru  Joined: 05/03/2018 Location: NetherlandsPosts: 5059 |
Hi Gerald, The correct syntax is: PIO ASSEMBLE 1,"SET PINS,1" So it is PINS And it needs a comma to separate the value. Volhout P.S. At the beginning of the sequel "PIO explained" there was no build in assembler yet in PicoMite. So it is very well possible that the menomics where inaccurately written. Edited 2024-11-27 00:42 by Volhout PicomiteVGA PETSCII ROBOTS |
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| ville56 Senior Member Joined: 08/06/2022 Location: AustriaPosts: 221 |
Many thanks Vollhout, but where did you get this information from? I could not find this. Gerald 73 de OE1HGA, Gerald |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 10246 |
https://datasheets.raspberrypi.com/pico/raspberry-pi-pico-c-sdk.pdf |
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| ville56 Senior Member Joined: 08/06/2022 Location: AustriaPosts: 221 |
Ahhh, now i see .... thanks Gerald 73 de OE1HGA, Gerald |
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| Volhout Guru Joined: 05/03/2018 Location: NetherlandsPosts: 5059 |
Hi Gerald, Honestly...try and error... Your program should look like this. PIO ASSEMBLE 1,".program anyname" PIO ASSEMBLE 1,".list 1" // here comes your program PIO ASSEMBLE 1,".end program list" if you want to assemble instructions, just add them in the section // here comes the program When you RUN the program, there are 2 possibilities: 1/ you get a list of PIO codes, and then the prompt (the end of the program). That is succesfull compiled. 2/ you get some PIO codes, and then an error message. That is the instruction that fails. Then you try with either adding a comma, or brackets, or whatever, until it compiles correct. But as a guide you can look at chapter 3 of the RP2040 datasheet, where the menmonics are explained. Note that the mnemonic syntax change when you configure the PIO different (i.e. using delay/sideset in some balance). So you may have to experiment a bit. I guess the PIO compiler is taken from RP's source, so there may be a good description of the mnemonics on their website. But I did not find it. I just used the datasheet, and try-and-error. I knew that the datasheet specifies "PINS" and not "PIN" for the field in the SET instruction (I did a lot of reading in the datasheet, and luckily I remembered). Volhout Volhout Edited 2024-11-27 01:17 by Volhout PicomiteVGA PETSCII ROBOTS |
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| PhenixRising Guru Joined: 07/11/2023 Location: United KingdomPosts: 1361 |
Some good PIO examples |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7871 |
The mnemonics are crazy... :) There aren't many *instructions* but the number of slight variations on many of them can get ridiculous. lol Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| ville56 Senior Member Joined: 08/06/2022 Location: AustriaPosts: 221 |
Thanks to all for the help. This forum is really living how to help each other. Fantastic work .... and yes, i'm now carefully reading the PIO section in the datasheet, trying to understand .... the first tiny program already runs. Gerald 73 de OE1HGA, Gerald |
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| Volhout Guru Joined: 05/03/2018 Location: NetherlandsPosts: 5059 |
Hi Phenix, The issue is that the PIO mnemonics do not follow a logical pattern, hence the try and error. in example: SET PINS,1 requires a comma between PINS and 1 JMP X-- 1 where 1 is an address to JMP to under condition X=0, post decrement X does not accept a comma between X-- and 1 OUT PINS,1 SIDE 1 Requires 1 comma for PINS, but no comma for the SIDE and 1 OUT PINS,1 [2] Uses brackets to indicate a delay of 2 clocks in the command. That is deviating from the written text like SIDE. On the other hand, you can't go wrong with that one... Feels a bit like "put together as we go" in stead of a logical syntax. Volhout P.S. Gerald, if you look at python examples for PIO, the assembly mnemonics should 1:1 work in MMBasic. Completely different is the python configuration of the PIO's. For that you better look at the user manual of MMBasic. Python may only confuse you. Note that the EXECCTRL, PINCTRL helper functions in MMBasic just fill in bits in the EXECCTRL and PINCTRL registers that can be found in the RP2040 datasheet in the PIO register map. And there they are explained quite good. Go to the register map, and browse until you find the register you are interested in. Edited 2024-11-27 06:36 by Volhout PicomiteVGA PETSCII ROBOTS |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7871 |
It really did my head in.... lol Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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